Mds-4310 Radio Transceiver

About This Manual

175 Science Parkway, Rochester, N.Y. 14620, U.S.A.Sales & Customer Support: +1 (716) 242-9600FAX–All Services: +1 (716) 242-9620World Wide Web: http://www.microwavedata.com/

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A CALIFORNIA MICROWAVE DIVISION

MDS 4310350–512 MHZ

RADIO TRANSCEIVER

ANTENNA

INTERFACE

TD IN RD

TR MR CD 13.8 VDC+ –

Installation, Operation & Field Maintenance

Covering the MDS 4310 Transceiver with the 05-2314Axx PCB,the MDS 4350 & 4355 Packaged Systems and All Basic Options

MDS 05-2415A01, Rev. ASEPTEMBER 1994

Model Number Information

The Particular Model covered in this manual is also sometimes referred to as the MDS 4310A.

MDS 2415A01, Rev. A Front Cover-B

MDS 4310 QUICK START GUIDEBelow are the basic steps for installing the MDS 4310 (350—512 MHz) Data Transceiver. The infor-mation in parentheses indicates the chapters in this manual where detailed explanations are found.

1. Verify radio set-up parameters. (Chapters 2 & 3)

Check the test data sheets packed with the transceiver to be sure the radio is properly configuredfor the intended application. Check especially for these items:

• Proper configuration of software selectable settings such as, CTS delay, soft carrier dekey(SCD), squelch tail eliminator (STE), time-out timer (TOT) and PTT delay. Chapter 3 givesinstructions for setting these parameters.

• Transmit and Receive frequencies.(Should be the same as those listed on the station license.)

• Transmitter RF power output.

• Loopback Code.(Default loopback code consists of the last four digits of the radio’s serial number.)

• Transmit modulation and audio input characteristics.

• Modem speed (if radio is modem-equipped).

2. Securely mount the transceiver. (Chapter 2)

• Use the MDS supplied mounting brackets and four screws or bolts (fasteners not provided).

• Choose a mounting location that allows easy access to the connectors on the end of the radioand allows an unobstructed view of the LED status indicators.

3. Install and connect the antenna system to the radio. (Chapter 2)

• Use good quality, low loss coaxial cable.

• Keep the antenna feedline as short as possible.

• Avoid sharp bends in the coaxial cable.

• Preset the antenna in the direction of the master station.

• Properly waterproof the antenna connector.

4. Connect and apply DC power to the radio. (Chapter 2)

• Set supply voltage to a nominal 13.8 volts.

• Observe polarity.

• Power cord must be properly fused (3 Amperes).

• Plug in the power plug and tighten the retaining screw.

5. Verify radio communications by observing the LED display. (Chapter 2)

• See Tables 2-2 and 2-3 for interpretation of status LEDs.

• Refine the antenna heading by using a DC voltmeter or Hand-Held Terminal (HHT) to measurethe radio’s received signal (RSSI).

6. Connect the data equipment to the radio INTERFACE connector. (Chapter 2)

• Connection must be made with a DB-25 Male (25 pin) connector.

• Connect only the required pins. Do not use a straight-through RS-232 cable with all pins wired.

• Verify the equipment connected to the INTERFACE connector is configured as DTE. The radiois configured as DCE (data communications equipment).

• Pin connections for the INTERFACE connector are summarized in Table 2-1.

MDS P/N 05-2515A01, Rev. ASEPTEMBER 1994

MDS 4310350–512 MHz RADIO TRANSCEIVER

Including the…

MDS 4350 and MDS 4355 PACKAGE MODEL RADIOS

INSTALLATION, OPERATIONAND

FIELD MAINTENANCE

Copyright © 1994Microwave Data Systems

All Rights Reserved

MICROWAVE DATA SYSTEMS175 Science Parkway, Rochester, New York 14620Telephone No.: 716-242-9600, FAX No.: 716-242-9620

The following are trademarks…Thruline™—Bird, Inc.

HELIAX™—Andrew Corporation.PCTALK™—The Headlands Press, Inc.

PCPLUS™—DataStorm Technologies, Inc.PROCOMM™—DataStorm Technologies, Inc.

If further assistance with this product is required, please contact:

MICROWAVE DATA SYSTEMSA Division of California Microwave Incorporated

175 Science ParkwayRochester, New York 14620

Telephone No.: 716-242-9600FAX No.: 716-242-9620

Copyright © 1994 by Microwave Data SystemsAll rights reserved.

MDS 2141A01, Rev. A i

TABLE OF CONTENTS

CHAPTER 1—GENERAL

INTRODUCTION ------------------------------------------------------------------------------------------------------ 1-1

APPLICATIONS-------------------------------------------------------------------------------------------------------- 1-1

TERMS “ANALOG” AND “DIGITAL” ---------------------------------------------------------------------------- 1-2

MDS 4310 MODULATION TECHNIQUES ----------------------------------------------------------------------- 1-2

MICROCONTROLLER FEATURES ------------------------------------------------------------------------------- 1-2

SOFT CARIER DEKEY ----------------------------------------------------------------------------------------------- 1-3

CONTROL INPUTS AND OUTPUTS ------------------------------------------------------------------------------ 1-3MODEL NUMBER CODES -------------------------------------------------------------------------- 1-4MAIN PRINTED CIRCUIT BOARD MODELS -------------------------------------------------- 1-4

SPECIFICATIONS ----------------------------------------------------------------------------------------------------- 1-5

OPTIONAL EQUIPMENT, ACCESSORIES and CERTIFICATIONS -------------------------------------- 1-10Special Certifications --------------------------------------------------------------------------------- 1-101200 BPS Bell 202T Modem------------------------------------------------------------------------ 1-114800 BPS Modem------------------------------------------------------------------------------------- 1-119600 BPS Modem------------------------------------------------------------------------------------- 1-11Audio Processing Module---------------------------------------------------------------------------- 1-11Order Wire Module ----------------------------------------------------------------------------------- 1-11Remote Maintenance Module (Internal)—P/N 03-1958A01 ----------------------------------- 1-11Hand-Held Terminal ---------------------------------------------------------------------------------- 1-12RS-232 to RS-422 Converter Assembly—P/N 01-2358A01------------------------------------ 1-12TTL to RS-232 Converter Assembly --------------------------------------------------------------- 1-12

CHAPTER 2—INSTALLATION

OVERVIEW ------------------------------------------------------------------------------------------------------------- 2-1

SURFACE MOUNTING ---------------------------------------------------------------------------------------------- 2-2

EXTERNAL CONNECTIONS --------------------------------------------------------------------------------------- 2-4ANTENNA Connector --------------------------------------------------------------------------------- 2-4DC IN (Power) Connector ----------------------------------------------------------------------------- 2-4INTERFACE Connector ------------------------------------------------------------------------------- 2-4INTERFACE Connector Pin Functional Descriptions --------------------------------------------- 2-7

FRONT PANEL INDICATORS ------------------------------------------------------------------------------------ 2-11

TRANSCEIVER CONFIGURATION JUMPERS --------------------------------------------------------------- 2-12J14—Receiver Audio Output Phase ---------------------------------------------------------------- 2-13J16—Full Duplex Option Connector --------------------------------------------------------------- 2-13

MODEMS—GENERAL --------------------------------------------------------------------------------------------- 2-13Introduction -------------------------------------------------------------------------------------------- 2-13The Role of the Modem ------------------------------------------------------------------------------ 2-14RTS and CTS Signals ------------------------------------------------------------------------------- 2-14DCD Signal -------------------------------------------------------------------------------------------- 2-14

POWER REQUIREMENTS----------------------------------------------------------------------------------------- 2-14

ANTENNAS AND FEEDLINES----------------------------------------------------------------------------------- 2-15Antenna Selection and Mounting ------------------------------------------------------------------- 2-15Feedline Selection------------------------------------------------------------------------------------- 2-16Feedline Installation ---------------------------------------------------------------------------------- 2-17

TOC Hotlink Information

The Chapter Titles are the only hot links in this Table of Contents.

ii TABLE OF CONTENTS MDS 2141A01, Rev. A

CHAPTER 3—PROGRAMMING AND DIAGNOSTICS

INTRODUCTION ------------------------------------------------------------------------------------------------------ 3-1

TERMINAL CONNECTION AND STARTUP ------------------------------------------------------------------- 3-1Opening The Diagnostic Channel -------------------------------------------------------------------- 3-3

CAPABILITIES OF THE HHT -------------------------------------------------------------------------------------- 3-4Review Operating Parameters and Diagnostic Information -------------------------------------- 3-4Setting the Operating Parameters--------------------------------------------------------------------- 3-5Program User Information ---------------------------------------------------------------------------- 3-5

USING THE HAND-HELD TERMINAL -------------------------------------------------------------------------- 3-5Command Syntax--------------------------------------------------------------------------------------- 3-5Shift Key ------------------------------------------------------------------------------------------------- 3-5Backspace (BKSP) Key ------------------------------------------------------------------------------- 3-5Error Messages------------------------------------------------------------------------------------------ 3-6Closing the Diagnostic Channel ---------------------------------------------------------------------- 3-6

PROGRAMMING EXAMPLES ------------------------------------------------------------------------------------- 3-6

PROGRAMMING OWNER’S INFORMATION ----------------------------------------------------------------- 3-8

PASSWORD PROTECTION----------------------------------------------------------------------------------------- 3-8

DIAGNOSTIC EVALUATION -------------------------------------------------------------------------------------- 3-8Test Modes ---------------------------------------------------------------------------------------------- 3-9

EQUIPMENT DIAGNOSTICS DEFINITIONS------------------------------------------------------------------- 3-9

DIAGNOSTIC EXAMPLES----------------------------------------------------------------------------------------- 3-10RF Power Output Check ----------------------------------------------------------------------------- 3-10Received Signal Strength Indication (RSSI) Check ---------------------------------------------- 3-10

PROGRAMMING AND TEST COMMANDS ------------------------------------------------------------------- 3-11

HAND-HELD TERMINAL SETUP DEFAULTS --------------------------------------------------------------- 3-13

HAND-HELD TERMINAL WIRING ----------------------------------------------------------------------------- 3-14Adapter Plug Wiring ---------------------------------------------------------------------------------- 3-14

HHT ALTERNATIVES ---------------------------------------------------------------------------------------------- 3-15Cable Wiring for a PC or ASCII Terminal -------------------------------------------------------- 3-15

CHAPTER 4—FIELD TESTS AND ADJUSTMENTS

GENERAL -------------------------------------------------------------------------------------------------------------- 4-1

TEST EQUIPMENT REQUIRED ----------------------------------------------------------------------------------- 4-1

CONSTRUCTING A DATA TERMINAL EMULATOR-------------------------------------------------------- 4-3

REMOTE MAINTENANCE CONSIDERATIONS--------------------------------------------------------------- 4-5

INTRODUCTION TO FIELD TESTS & ADJUSTMENTS ----------------------------------------------------- 4-6

TEST PROCEDURES:Basic Transceiver Checks ----------------------------------------------------------------------------- 4-7Transmit Frequency, Squelch, Deviation and Receive Audio Output

For Radios with No Internal Modem----------------------------------------------------- 4-10For Radios with MDS’s Internal 1200 BPS Modem----------------------------------- 4-11For Radios with MDS’s Internal 4800 BPS Modem----------------------------------- 4-14For Units with MDS’s Internal 9600 BPS Modem ------------------------------------ 4-16

REMOTE MAINTENANCE MODULE—Loopback Code Programming, Mode Selection, Calibration & Testing ---------------------- 4-19

MDS 2141A01, Rev. A TABLE OF CONTENTS iii

CHAPTER 5—THEORY OF OPERATION

RECEIVE FRONT END ----------------------------------------------------------------------------------------------- 5-1

HIGH IF ------------------------------------------------------------------------------------------------------------------ 5-1

LOW IF ------------------------------------------------------------------------------------------------------------------- 5-1

RECEIVE AUDIO ------------------------------------------------------------------------------------------------------ 5-1

SQUELCH --------------------------------------------------------------------------------------------------------------- 5-2

POWER SUPPLY------------------------------------------------------------------------------------------------------- 5-2

TRANSMIT POWER AMPLIFIER---------------------------------------------------------------------------------- 5-3

ANTENNA SWITCH -------------------------------------------------------------------------------------------------- 5-3

DIRECTIONAL COUPLER------------------------------------------------------------------------------------------- 5-3

KEYLINE AND CONTROL CIRCUITS --------------------------------------------------------------------------- 5-3

RADIO DISABLE ------------------------------------------------------------------------------------------------------ 5-3

AUDIO/DATA MODULATION INPUT SWITCHING ---------------------------------------------------------- 5-4

MICROCONTROLLER/EEPROM ---------------------------------------------------------------------------------- 5-4

DIAGNOSTICS DATA CONTROL --------------------------------------------------------------------------------- 5-4

TRANSMIT AUDIO --------------------------------------------------------------------------------------------------- 5-5

PLL/SYNTHESIZER--------------------------------------------------------------------------------------------------- 5-5

RS-232 DATA INTERFACE------------------------------------------------------------------------------------------ 5-5

LED INDICATORS ---------------------------------------------------------------------------------------------------- 5-5

CHAPTER 6—TROUBLESHOOTINGThis section contains basic field troubleshooting assistance for the transceiver system.

APPENDIX A—1200 BPS BELL 202T COMPATIBLE MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- A-1

SPECIFICATIONS ---------------------------------------------------------------------------------------------------- A-1

ALIGNMENT ---------------------------------------------------------------------------------------------------------- A-1

THEORY OF OPERATION------------------------------------------------------------------------------------------ A-2

APPENDIX B—4800 BPS FSK MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- B-1

SPECIFICATIONS ---------------------------------------------------------------------------------------------------- B-1

INSTALLATION ------------------------------------------------------------------------------------------------------ B-1

ALIGNMENT ---------------------------------------------------------------------------------------------------------- B-1

THEORY OF OPERATION------------------------------------------------------------------------------------------ B-1

APPENDIX C—9600 BPS FSK MODEM

INTRODUCTION ----------------------------------------------------------------------------------------------------- C-1

SPECIFICATIONS ---------------------------------------------------------------------------------------------------- C-1

INSTALLATION ------------------------------------------------------------------------------------------------------ C-1

ALIGNMENT ---------------------------------------------------------------------------------------------------------- C-1

THEORY OF OPERATION------------------------------------------------------------------------------------------ C-1

iv TABLE OF CONTENTS MDS 2141A01, Rev. A

APPENDIX D—REMOTE MAINTENANCE MODULE

INTRODUCTION ----------------------------------------------------------------------------------------------------- D-1

OPERATION ---------------------------------------------------------------------------------------------------------- D-1

MODULE ADJUSTMENTS & CALIBRATION ---------------------------------------------------------------- D-2

DETERMINING THE PRESENCE OF A REMOTE MAINTENANCE MODULE ----------------------- D-2

INSTALLATION & REPLACEMENT ---------------------------------------------------------------------------- D-3

TESTING THE LOOPBACK CODE ------------------------------------------------------------------------------ D-4

TROUBLESHOOTING ---------------------------------------------------------------------------------------------- D-4

THEORY OF OPERATION ----------------------------------------------------------------------------------------- D-5

APPENDIX E—ORDER WIRE MODULE

INTRODUCTION ------------------------------------------------------------------------------------------------------ E-1

THEORY OF OPERATION ------------------------------------------------------------------------------------------ E-2

APPENDIX F—MDS 4355 REMOTE RADIO PACKAGED SYSTEM

GENERAL INFORMATION----------------------------------------------------------------------------------------- F-1

INTERFACE ASSEMBLIES----------------------------------------------------------------------------------------- F-2Analog Interface Assembly—P/N 03-1105A21 --------------------------------------------------- F-2RS-232/TTL Digital Interface Assembly—P/N 03-1467A21 ------------------------------------ F-2

POWER CONNECTIONS -------------------------------------------------------------------------------------------- F-3Primary Power—J3------------------------------------------------------------------------------------- F-3Power for Accessories --------------------------------------------------------------------------------- F-3Back-up Battery ---------------------------------------------------------------------------------------- F-3

ANALOG INTERFACE BOARD CONNECTIONS—P/N 03-1105A21, Rev. C ---------------------------- F-4Audio and Keyline—J1-------------------------------------------------------------------------------- F-4Additional Interface Connections -------------------------------------------------------------------- F-4Audio Alignment --------------------------------------------------------------------------------------- F-5

DIGITAL RS-232/TTL INTERFACE BOARD CONNECTIONS, P/N 03-1467A21 --------------------- F-11Summary----------------------------------------------------------------------------------------------- F-11RS-232 Digital Interface Connections ------------------------------------------------------------- F-12TTL Digital Interface Connections ---------------------------------------------------------------- F-12Additional Interface Connections ------------------------------------------------------------------ F-12Order Wire Audio Alignment ---------------------------------------------------------------------- F-12

APPENDIX G—MDS 4355 REMOTE RADIO PACKAGED SYSTEM

GENERAL INFORMATION---------------------------------------------------------------------------------------- G-1

CUSTOMER MODIFICATION ------------------------------------------------------------------------------------ G-2

MOUNTING ----------------------------------------------------------------------------------------------------------- G-2

INTERFACE ASSEMBLIES—Summary ------------------------------------------------------------------------- G-5Analog Interface/Utility Assembly—P/N 03-2110A01 ------------------------------------------ G-5RS-232 Digital Interface and Utility Board—P/N 03-2115A01 -------------------------------- G-5

USING THE MDS HAND-HELD TERMINAL------------------------------------------------------------------ G-5

POWER CONNECTIONS ------------------------------------------------------------------------------------------- G-6Primary Power—TB2--------------------------------------------------------------------------------- G-6Power for Accessories -------------------------------------------------------------------------------- G-7Back-up Battery --------------------------------------------------------------------------------------- G-7

Packaged Model Information

The Packaged Model (MDS 4350/4360) information is now is a separate manual. Please refer to MDS P/N 05-2818A01.

MDS 2141A01, Rev. A TABLE OF CONTENTS v

ANALOG INTERFACE/UTILITY BOARD CONNECTIONS—P/N 03-2110A01------------------------- G-8Audio and Keyline—TB1----------------------------------------------------------------------------- G-8Additional Interface Connections -------------------------------------------------------------------- G-8Audio Alignment--------------------------------------------------------------------------------------- G-9Order Wire Audio Alignment ------------------------------------------------------------------------ G-9

DIGITAL INTERFACE/UTILITY BOARD CONNECTIONS—P/N 03-2115A01— -------------------- G-13Summary ---------------------------------------------------------------------------------------------- G-13RS-232 Digital Interface Connections ------------------------------------------------------------ G-13Additional Interface Connections ------------------------------------------------------------------ G-14Order Wire Audio Alignment ---------------------------------------------------------------------- G-14

APPENDIX H—MDS 4310-HLDATA TRANSCEIVER FOR USE IN HAZARDOUS LOCATIONS

INTRODUCTION ----------------------------------------------------------------------------------------------------- H-1

CONDITIONS OF APPROVAL ------------------------------------------------------------------------------------ H-1

APPENDIX I—CANADIAN CERTIFICATION

RSS APPROVALS ----------------------------------------------------------------------------------------------------- I-1

RESTRICTIONS -------------------------------------------------------------------------------------------------------- I-1

APPENDIX J—AUDIO PROCESSING MODULE

INTRODUCTION ------------------------------------------------------------------------------------------------------ J-1

SPECIFICATIONS ----------------------------------------------------------------------------------------------------- J-1

ALIGNMENT ----------------------------------------------------------------------------------------------------------- J-2

CONFIGURATION ---------------------------------------------------------------------------------------------------- J-2

TABLES

Table 2-1. DB-25 Interface Connector Pin Functions-------------------------------------------------------------- 2-6

Table 2-2. External Indicators For Radios Without Internal Modems ----------------------------------------- 2-11

Table 2-3. External Indicators For Radios WithInternal Modems---------------------------------------------- 2-12

Table 2-4. J11–External Interface TTL/RS-232 ------------------------------------------------------------------ 2-13

Table 2-5. J14 Receiver Audio Output Normal/Inverted -------------------------------------------------------- 2-13

Table 2-6. Signal Loss versus Cable Length and Type ---------------------------------------------------------- 2-16

Table 3-1. Diagnostic and Control Capabilities ------------------------------------------------------------------- 3-10

Table 3-2. Programming and Test Commands -------------------------------------------------------------------- 3-11

Table 3-3. Hand-Held Terminal Operating Defaults ------------------------------------------------------------- 3-14

Table 4-1. Main Circuit Board Potentiometer Settings for Remote Maintenance------------------------------ 4-6

Table 4-2. Test Procedure Reference Chart ------------------------------------------------------------------------- 4-6

Table B-1. Settings for the MDS 4800 bps Modem’s Configuration Switch S1 ------------------------------ B-3

Table C-1. Settings for the MDS 9600 bps Modem’s Configuration Switch S1 ------------------------------ C-2

Table F-1. Interface Board J1 Connectors ------------------------------------------------------------------------- F-11

Table G-1. Interface Board TB1 Connectors -------------------------------------------------------------------- G-13

Table J-1. P/N 03–2301A01 Configuration Switch Settings ------------------------------------------------------ J-2

vi TABLE OF CONTENTS MDS 2141A01, Rev. A

ILLUSTRATIONS

Figure 1-1. MDS 4310 Model Number Codes---------------------------------------------------------------------- 1-4

Figure 1-2. Printed Circuit Model Number Location -------------------------------------------------------------- 1-5

Figure 1-3. MDS 4310 Transceiver—Major Assemblies -------------------------------------------------------- 1-13

Figure 2-1. Mounting Dimensions—Front View------------------------------------------------------------------- 2-3

Figure 2-2. Mounting Dimensions—Bottom View ---------------------------------------------------------------- 2-3

Figure 2-3. External Connections------------------------------------------------------------------------------------- 2-5

Figure 2-4. Received Signal Strength Indicator Calibration Chart (Typical)---------------------------------- 2-10

Figure 2-5. Location of Configuration Jumpers ------------------------------------------------------------------- 2-12

Figure 2-6. Detail of Configuration Jumpers—J14 --------------------------------------------------------------- 2-13

Figure 3-1. Hand-Held Terminal Connected to the MDS 4310 Transceiver ----------------------------------- 3-2

Figure 3-2. MDS 4355 Packaged Transceiver ---------------------------------------------------------------------- 3-2

Figure 3-2. Hand-Held Terminal Keypad --------------------------------------------------------------------------- 3-6

Figure 3-3. HHT Initialization Display ----------------------------------------------------------------------------- 3-13

Figure 3-4. DB-25 Interface Adapter Wiring ---------------------------------------------------------------------- 3-14

Figure 3-5. DB-9 to DB-25 Interface Cable Wiring -------------------------------------------------------------- 3-15

Figure 3-6. DB-25 to DB-25 Interface Cable Wiring------------------------------------------------------------- 3-15

Figure 4-1. Remote Data Terminal Emulator Wiring-------------------------------------------------------------- 4-4

Figure 4-2. Construction Options for Building a Data Terminal Emulator ------------------------------------- 4-4

Figure 4-3. VCO Lock Voltage Test Point -------------------------------------------------------------------------- 4-9

Figure 4-4. 1200 bps AFSK Modem -------------------------------------------------------------------------------- 4-13

Figure 4-5. 4800 BPS FSK Modem--------------------------------------------------------------------------------- 4-15

Figure 4-6. 9600 BPS FSK Modem--------------------------------------------------------------------------------- 4-17

Figure 4-7. Remote Maintenance Module-------------------------------------------------------------------------- 4-19

Figure 4-8. Remote Maintenance Screen--------------------------------------------------------------------------- 4-23

Figure 4-9. MDS 4310 Transceiver PC Board Test Points and Adjustments --------------------------------- 4-25

Figure 5-1. MDS 4310 Transceiver Block Diagram --------------------------------------------------------------- 5-7

Figure A-1. 1200 bps Modem PC Board --------------------------------------------------------------------------- A-1

Figure A-2. Bell 202T Compatible Modem Block Diagram----------------------------------------------------- A-3

Figure B-1. MDS 4800 bps Modem Block Diagram -------------------------------------------------------------- B-2

Figure B-2. MDS 4800 bps Modem Assembly Diagram --------------------------------------------------------- B-3

Figure C-1. MDS 9600 bps Modem Block Diagram -------------------------------------------------------------- C-3

Figure C-2. 9600 bps Modem Assembly Diagram ----------------------------------------------------------------- C-3

Figure D-1. Remote Maintenance Module, P/N 03-1958A01--------------------------------------------------- D-2

Figure E-1. Order Wire Module -------------------------------------------------------------------------------------- E-1

Figure E-2. Order Wire Board Component Layout ---------------------------------------------------------------- E-2

Figure E-3. Order Wire Block Diagram ----------------------------------------------------------------------------- E-3

Figure F-1. MDS 4350 Interior View -------------------------------------------------------------------------------- F-1

Figure F-2. MDS 4350 Features & Dimensions -------------------------------------------------------------------- F-2

Figure F-3. 03-1105A21 Keying Options, Analog Interface Assembly----------------------------------------- F-6

Figure F-4. MDS 4350 Packaged System Wiring Diagram ------------------------------------------------------ F-7

MDS 2141A01, Rev. A TABLE OF CONTENTS vii

Figure F-5. Analog Interface Assembly 03-1105A21 ------------------------------------------------------------- F-9

Figure F-6. MDS 4350 Packaged System Wiring Diagramwith 03-1467A21 RS-232/TTL Interface ---------------------------------------------------------- F-13

Figure F-7. RS-232/TTL Interface Assembly 03-1467A21 ---------------------------------------------------- F-15

Figure G-1. MDS 4355 Interior (AC Version) with Fiberglass Enclosure Removed ------------------------- G-1

Figure G-2. MDS 4355 Dimensions, Feed-Through Couplings & Mounting Points ------------------------- G-2

Figure G-3. Exploded View of DC Version of System ----------------------------------------------------------- G-3

Figure G-4. Exploded View of AC Version of System ----------------------------------------------------------- G-4

Figure G-5. Plugs for Primary Power TB2 and Interface TB1 Connectors ------------------------------------ G-7

Figure G-6. Keying Options for the 03-2110A01 Analog Interface/Utility PC Board --------------------- G-10

Figure G-7. MDS 4355 Packaged System Wiring Diagramwith the 03-2110A01 Analog Interface/Utility Board ------------------------------------------ G-11

Figure G-8. Analog Interface Assembly 03-2110A01 ---------------------------------------------------------- G-12

Figure G-9. MDS 4355 Packaged System Wiring Diagram ith the03-2115A01 RS-232 Digital Interface & Utility PCB ------------------------------------------ G-15

Figure G-10. RS-232 Digital Interface and Utility Board ------------------------------------------------------ G-16

Figure J-1. Audio Processing Module Installation Diagram ------------------------------------------------------ J-1

Figure J-3. 03-2301A01 Audio Processing Module ---------------------------------------------------------------- J-2

viii TABLE OF CONTENTS MDS 2141A01, Rev. A

About This ManualThis manual covers three models in the MDS 4300 Series of 450 MHz radio transceivers.The MDS 4310 is the basic transceiver, and it is the main focus of this manual. The MDS4350 and MDS 4355 are packaged weatherproof models, which include the MDS 4310 radioplus a power supply, back-up battery and interface/utility board, all mounted in a NEMA 4enclosure. Appendix F of this manual covers the main features of the MDS 4350 andAppendix G covers the MDS 4355. All discussions relating only to the MDS 4350 and MDS4355 Packaged models will be clearly marked.

The following is a brief summary of the contents in each chapter of the manual.

Chapter 1—General, provides a general introduction to the MDS 4310 Transceiver and itsstandard and optional equipment. A specifications table provides a detailed summary of theradio’s electrical and mechanical features.

Chapter 2—Installation, contains steps for installation, hookup and checkout of the MDS4310 Transceiver. Recommendations are also provided for feedline and antenna selection,connection to external equipment, jumper configuration settings and other requirements forplanning a successful radio installation.

Chapter 3—Programming and Diagnostics, gives procedures for connecting a Hand-HeldTerminal, or a standard ASCII Terminal to the radio for accessing and controlling thetransceiver’s operating parameters and performing diagnostic checks.

Chapter 4—Field Tests and Alignments, contains detailed procedures for testing andadjusting the equipment to ensure maximum performance. The procedures here are notrequired for normal installations, but can be performed as an aid in diagnosing a suspectedproblem, or following replacement or repair of an assembly.

Chapter 5—Theory of Operation, provides an overview of the circuits comprising theMDS 4310 Transceiver. The text is supported with an oversized block diagram at the end ofthe chapter to aid in understanding the material.

Chapter 6—Troubleshooting System Problems, contains recommended evaluationprocedures for system troubles, and suggests possible solutions.



MDS 05-2415A01, Rev. A 1-1

CHAPTER 1—GENERAL

INTRODUCTION

The MDS 4310 Transceiver offers continuous duty, high-performance data communicationsin the 390–470 MHz frequency band. The transceiver is fully synthesized and can be pro-grammed to operate on 12.5 kHz and 25 kHz channels within this range.

The MDS 4310 Transceiver can be supplied with a MDS 2314Axx main PC board or a MDS2013Axx main PC board. Although the two PC boards are similar, this manual coverstransceivers with the 2314Axx main PC board. Refer to the MDS 05-2141A01 manual forspecific information regarding transceivers equipped with the 2013Axx main PC board.

The Transceiver’s design is highlighted by a compact and rugged die-cast aluminum casewhich houses the basic RF unit, and all diagnostic and modem options. The MDS 4350 andMDS 4355 are alternate weatherproof models which include the MDS 4310 radio plus apower supply, back-up battery and interface/utility board, all mounted in a NEMA 4Xenclosure. Appendix F of this manual covers the main features of the MDS 4350 andAppendix G covers the MDS 4355 Package.

The contents of this manual center on the MDS 4310 Data Transceiver. All discussionsrelating only to the MDS 4350 and MDS 4355 Packaged models are clearly marked.

+

–

M D S 2000 D A T A T R A N S C E IV E R

TRANSCEIVER

The MDS 4310 Data Transceiver The MDS 4350 Packaged Radio(MDS 4355 Similar in appearance)

APPLICATIONS

The MDS 4310 Data Transceiver is a single channel, half-duplex, radio designed for use inmultiple address systems (MAS) such as those licensed under Part 90 of the FederalCommunications Commission rules, with an emission designation of F1D, F2D, or F3D,depending on application and configuration.

Continued on next page.

1-2 GENERAL MDS 05-2415A01, Rev. A

As a component of point-to-multipoint data telemetry systems, the MDS 4310 Transceiver iswell suited for such applications as:

• Supervisory Control and DataAcquisition (SCADA)

• Telemetry Systems• Energy Distribution Automation

• Information Systems• Oil Fields and Pipelines• Alarm Monitoring• Security

MDS 4000 Series radio systems offer the advantage of a frequency band which in many areasis specially coordinated to provide protection from co-channel interference. Because these areprimarily data-only channels, voice users are not likely to interfere with data transmissionand reception.

TERMS “ANALOG” AND “DIGITAL”

In all MDS literature, the terms “analog” and “digital” are commonly used to describe themodulation modes and other signal characteristics of various products. The following areexamples of how these terms are commonly used in this manual.

Analog Modem, Analog Radio, Analog Mode—These terms relate to equipment or operating modes using linear frequency modulationand detection techniques. The circuitry handles analog communication signals, such asaudio frequency shift keying (AFSK) or analog voice frequency signals through thesystem. Generally, these products or modes operate in the 50 to 1200 bits per second(bps) data range in non-voice applications. Modulation sources include an internal MDSbrand 1200 bps modem or external 4-wire audio sources such as AFSK modems.

Digital Modem, Digital Radio, Digital Mode—These terms relate to equipment or operating modes using non-linear frequency shiftkeying modulation and detection techniques. The signal may alternate between two orthree discrete frequencies (FSK) depending on equipment configuration. Generally, theseproducts or modes operate in the 4800 and 9600 bps range.

MDS 4310 MODULATION TECHNIQUES

The MDS 4310 Transceiver can be modulated by either audio frequency shift keying (AFSK)or frequency shift keying (FSK) controlled directly by the digital output of the MDS internalmodems. Alternatively, an external modem can be used for controlling AFSK transmission.

The MDS 4310 is capable of interfacing with data equipment at standard rates between 50and 4800 bits per second (bps) with an asynchronous interface to the local terminal unit. TheMDS 4310 provides a synchronous or asynchronous interface at data speeds of 1200, 4800and 9600 bps with one of the optional FSK modems installed internally.

MICROCONTROLLER FEATURES

The MDS 4310 Transceiver features an internal microcontroller that allows userprogramming and control of operating parameters and interrogation of diagnostic data.Programming of radio settings and monitoring of operating parameters can be done with aterminal unit connected through the transceiver’s DB-25 INTERFACE connector, eliminatingthe need to remove the radio from its mounting position or open its top cover. The terminalcan be either an MDS-supplied Hand-Held Terminal (HHT), or an IBM PC (or compatible)personal computer running MDS-supplied software, or other PC-based communications

MDS 05-2415A01, Rev. A GENERAL 1-3

software (such as PCPLUS™, PROCOMM™, PCTALK™, etc.). As a third alternative, anyterminal with an RS-232 serial port can also be used.

With one of these devices connected, the user can program the transmit and receivefrequencies, RTS/CTS delay time, PTT delay, soft carrier dekey, time-out-timer, loopbackcode and the MDS-patented Squelch Tail Eliminator circuit. In addition, an internal messagefield (up to 27 characters) can be entered to label each transceiver with its own identity.Password security and several other functions are also programmable.

Diagnostic functions that can be measured through the diagnostic module include receivedsignal strength indication (RSSI), various critical voltage levels, internal temperature,forward power, and antenna/feedline VSWR. When equipped with the remote maintenancemodule and used in a system with an MDS 4100 Series Master Station, several of thesediagnostic measurements can be sent over-the-air back to the master station for display by theassociated PC diagnostic software.

The internal micro-controller also provides basic indication of operating parameters andvalues. While not a substitute for calibrated test equipment, this is useful for quick fieldevaluations.

SOFT CARIER DEKEY

This feature can be used to keep the transmitter keyed for a short period of time (typically upto 5 ms) after the last data bit has been transmitted. This period of silence provides a clearindication that the message has ended and helps ensure no errors are introduced into the datastream as a result of the transmitter unkeying too soon. The soft carrier dekey feature can beselected or modified by using the HHT.

CONTROL INPUTS AND OUTPUTS

Four control inputs and outputs are provided on the MDS 4310 Data Transceiver’s 25-pin“D” INTERFACE connector. They are:

1. Receiver Squelch. This output goes low when the receiver is squelched, and ispulled high when the receiver squelch is open. When the squelch is open, this pinsupplies +8 Vdc through a 1 kΩ resistor.

2. Out-of-Lock Alarm. When this output is low (less than 0.5 Vdc), it indicates normaloperation. A logic high (greater than 4 Vdc) indicates a failure in the phase lock loopsignal source, or a transmitter time-out condition.

3. Received Signal Strength Indicator. This analog signal output supplies a receivedsignal strength indicator (RSSI) voltage on Pin 21 of the DB-25 connector. The RSSIvoltage is proportional to the strength of the signal present at the antenna connector,and provides a useful indication of signal levels between –120 dBm and –60 dBm.This can be especially helpful during installation to aid in aiming the station antennafor maximum received signal strength.

4. Radio Disable. When this input on Pin 12 of the INTERFACE connector senses aground, it disables or “turns off” most circuits in the radio, including transmit,receive, modem and diagnostic functions. This reduces power consumption, yetpreserves the radio’s ability to be brought quickly online. Total current drain in thedisabled state is less than 14 mA.

The annunciator or LED indicator panel on the transceiver’s face shows the radio’s basicperformance without removing the housing cover. For transceivers without a built-in modem,front-panel indicators are provided for primary power on, receive carrier detect, out-of-lock


alarm, transmit keyline activity and transmit status. When used with the modem option, anannunciator panel indicates the status of the RS-232 interface lines (TXD, RXD, DCD, RTS,CTS). If desired, the LED display can be turned off by moving a jumper inside the radio.This may be desirable in applications where power consumption must be kept to an absoluteminimum.

MODEL NUMBER CODES

The model number as found on the serial number label may be used to determine the generalhardware configuration of the radio as it was shipped from the factory. Figure 1-1 illustratesthe significance of the various characters in the radio’s serial number. The serial numberlabel is located on the end of the radio enclosure.

POWER SETTING(1) 12VDC

INTERFACE(0) 4-Wire Audio(2) 1200 BPS(A) 4800 BPS(D) 9600 BPS

DIAGNOSTICS(0) None(4) Remote Maint.

SAFETY CERTIFICATION(0) N/A(F) Factory Mutual / UL

OPERATION(R) Base/Remote

BANDWIDTH(1) 12.5 KHz

SEPARATION(5) 5–10 MHz/Simplex

REGULATORY CERTIFICATION(0) N/A(1) FCC (USA)(2) DOC RSS-119(3) DOC RSS-122 (Canada)

FREQUENCY RANGE(A) 390–406 MHz*(E) 450–470 MHz*(F) 406–430 MHz*(G) 350–370 MHz(H) 370–390 MHz(I) 390–410 MHz

* 2013 printed circuit board only

(J) 406–430 MHz(K) 430–450 MHz(L) 450–470 MHz(M) 470–490 MHz(N) 490–512 MHz

This information is subject to configuration and change. Contact MDS to verify certification.

4 3 1 0 R N 1 5 1

Figure 1-1. MDS 4310 Model Number Codes

MAIN PRINTED CIRCUIT BOARD PCB VARIATIONS

The MDS 4310 Transceiver may be equipped with a 2314Axx main PC board or a 2013Axxmain PC board. The significant difference is the frequency range. Although the two PCboards are similar, this manual covers transceivers with the 2314Axx main PC board whichhas a frequency range of 350 to 512 MHz. Refer to manual part number MDS 05-2141A01for specific information regarding transceivers equipped with the 2013Axx main PC boardwhich has a frequency range of 390 to 470 MHz. See Figure 1-2 for the location of the mainPCB part number label.

The main PC board part number can be identified without removing the housing cover. Referto Figure 1-1 to determine the transceiver frequency range. The frequency ranges identifiedwith a G, H I, J, K, L, M or N are equipped with the 2314Axx main PC board. The main PCboard part number can also be determined by using the HREV command via the HHT orterminal. The HREV command displays the main PC board part number and the revision level.

The nominal frequency operating range of the transceiver PCB can also be determined byusing the MOD command via the HHT or terminal. The MOD command displays the main PCboard model number and the revision level.

See Chapter 3 –Programming and Diagnostics for detailed information on the use of theHand-Held Terminal.


3

4

1

2

3 4

1 2

123

PRINTED CIRCUIT BOARD MODEL

LABEL

Figure 1-2. Printed Circuit Model Number Location

SPECIFICATIONS: MDS 4310 DATA TRANSCEIVER (2314 MAIN PC BOARD)

General

Frequency Range: 350–512 MHz (Nominal)

Operating Bands— 350–370 MHz, 370–390 MHz, 390–410 MHz,any one of eight: 406–430 MHz, 430–450 MHz, 450–470 MHz,

470–490 MHz, and 490–512 MHz

Frequency Programming: Programmable in 6.25 kHz increments to any channel pair in radio operating sub-band.

TX/RX Spacing: 0 (Simplex), 5 MHz, 10 MHz standard; othersare possible, consult with factory.

Primary Power—

Model 4310 Transceiver

Voltage: 13.8 Vdc Nominal(10.5–16.5 Vdc Operating Range)

TX Supply Current: 2.0 A typical, 2.5 A Maximum, at 13.8 VdcVaries with power output adjustment

RX Supply Current: 65 mA typical, without options installed orLED indicators turned OFF

Standby Current (Radio Inhibited) : 14 mA maximum

Connector: Integral part of power cable assembly(Six foot/1.8 meter cable assembly included)

Fuse: 3.0 A, 3AG, FB (Fast Blow);Holder part of cable assembly

Reverse Polarity Protection: Diode across primary power input withinternal 4 A plug-in fail-safe fuse.



General Continued

Model 4350 and 4355 Packaged Radios

Voltage: 120/220 Vac with 5 ampere-hourBattery Back-up (Standard)

12, 24, 48, & 125 Vdc (Optional)

DC Supply: Positive, Negative;Floating Ground with 24, 48, & 125 Vdc

TX Power Consumption: 50 watts maximum at rated output

RX Power Consumption: 5 watts maximum

Transient Protection: 2500 Volt Isolation on Voice Frequency (VF)Inputs and Outputs, Power Supply & Keying

Dimensions:

Model 4310 Transceiver 2.0" x 5.62" x 7.25"50 x 143 x 184 mm(Not including mounting hardware orconnector housings)

Model 4350 Packaged Radio 9.5" x 17.5" x 19.5"241 x 445 x 495 mm(Not including mounting hardware orconnector housings)

Model 4355 Packaged Radio 6.5" x 11.85" x 13.75"165 x 301 x 350 mm(Not including mounting hardware orconnector housings)

Weight:

Model 4310 Transceiver Maximum 3.5 Lbs./1.6 kgw/all options installed

Model 4350 Packaged Radio Maximum 33 Lbs/15.0 kgw/all options installed

Model 4355 Packaged Radio Maximum 21 Lbs/9.53 kgw/all options installed

Transmitter



470–490 MHz, and 490–512 MHz


TX/RX Spacing: 0 (Simplex), 5 MHz, 10 MHz standard; othersare possible, consult with factory.


Power Output: 5 Watts/+37 dBm (standard)at the ANTENNA Connector

Adjustable down to 0.5 watt/+27 dBm

Duty Cycle: 100%/Continuous

Output Impedance: 50 Ohms

Forward & Reflected Power Detector: Built-in

Frequency Stability: ± 0.00015% (1.5 PPM), –30°C to +60° C,For All Models

RF Channel Bandwidth: 12.5 kHz (25 kHz Compatible)

Spurious & Harmonic Emissions: –65 dBc

TX Response Time: ≤ 4 ms

Modulation Type: FSK—With 4800 and 9600 bps modemsFM—With 1200 bps AFSK modem

Deviation: ±2.5 kHz Maximum

Time-Out Timer: Internal; Programmable from 1–255 Seconds,or Off

Analog Model Audio InputCharacteristics—

Level: Adjustable, –20 to +10 dBmfor 2.5 kHz Deviation

Model 4310: 600 Ohms, UnbalancedModel 4350: 600 Ohms, Balanced,

4-Wire Audio

Frequency Response: Model 4310: +1 dB, –3 dB, 50–3000 HzModel 4350: +1 dB, –3 dB, 300–3000 Hz

Soft Carrier Dekey: Programmable from 0 to 255 ms in 1 ms stepsSoft Carrier Dekey factory set to…

0 ms with no internal modem0 ms with MDS 1200 baud modem2 ms with 4800 FSK internal modem4 ms with 9600 FSK internal modem

Transmitter Keying: Positive-going and negative-going,TTL-compatible keying inputs are provided.Inputs will operate with signal voltagesbetween 5 and 40 volts. Dry contact closuresare also suitable. Keyline input pins have aninput impedance of 10 kilohms and have built-in over-voltage protection up to ±40 volts.

PTT Delay: Programmable from 0-31 ms in 1 ms steps


Receiver



470–490 MHz, and 490–512 MHz


Type: Double Conversion Superheterodyne

Frequency Stability: ±0.00015% (1.5 PPM) –30° to +60° C,For All Models

Sensitivity for Analog Models: 12 dB SINAD at –117 dBm (0.3 µV)(at ANTENNA connector) w/de-emphasis OFF

12 dB SINAD at –119 dBm (0.25 µV) w/de-emphasis ON

Bit Error Rates: Analog/AFSK at 1200 bps:BER 1x10–6 at –110 dBm

Digital/FSK at 4800 bps:BER 1x10–6 at –110 dBm

Digital/FSK at 9600 bps:BER 1x10–6 at –108 dBm

Intermodulation: 75 dB Minimum (EIA)

IF Selectivity: 100 dB minimum at Adjacent Channel(± 25 kHz, one generator method, 20 dBquieting)

Desensitization: 70 dB minimum (EIA) on 25 kHz channels65 dB minimum (EIA) on 12.5 kHz channels

Spurious and Image Rejection: 85 dB Minimum

Analog Audio Output Characteristics—Frequency Response (Refer. to 1 kHz): Model 4310—Basic Transceiver:

Filtered, +1, –3 dB, 50 – 3000 Hz

Model 4310—with VOX Board:Filtered, +1, –3 dB, 50 – 3000 HzUnfiltered, +1, –3 dB, 50 – 4500 Hz

Model 4350:Filtered, +1, –3 dB, 300 – 3000 Hz

Level: Adjustable, – 20 to + 5 dBmModel 4310: 600 Ohms, UnbalancedModel 4350/55: 600 Ohms, Balanced

Harmonic Distortion: < 3%, All Models, Measured w/de-emphasis

RF Channel Bandwidth: 12.5 kHz (25 kHz compatible)

Received Signal Strength Indicator (RSSI): Built-in, Range: –120 dBm to –60 dBm

Squelch Opening Time: 2 ms


Diagnostics & Programming Interface (through INTERFACE connector)Signaling Standard: RS-232C Interface

Connector: DB-25

I/O Devices: • MDS Hand-Held Terminal

• IBM PC or compatible computer with CGA,EGA, VGA or Hercules Graphics™,DOS 2.0 or later and 640K of memory.

System Data Characteristics (through INTERFACE connector)

Signals: without modemTransmit Audio InputFiltered Receiver Audio OutputReceiver Unsquelched Sensor (RUS)Received Signal Strength Indicator (RSSI)Out-of-Lock AlarmPTT/ PTT

added with internal modemRS-232 Compatible Data LinesRXD TXDRTS CTSDCD DSRETC* TC*RC** w/synchronous FSK only

Data Rates—

AFSK: 50 to 9600 bps—Asynchronous audiointerface using external modems

30 to 1200 bps—Asynchronous w/internalBell 202T compatible modem

FSK: 50 to 4800 bps—Asynchronous, w/internaldirect FSK interface

4800 bps—Async/Synchronous, w/internaldirect FSK interface

9600 bps—Async/Synchronous, w/internaldirect FSK interface

Data Turn-Around Time: 10 ms, including RTS/CTS time delay withinternal modem installed

CTS Delay: 5 to 255 ms,Programmable in 1 ms increments


Environmental

Temperature Range: Full Performance: –30°C to + 60°COperational Performance: –40°C to +70°C

Humidity: 95% at + 40°C Non-Condensing

Case: Model 4310–Die-Cast Aluminum

Model 4350–Die-cast aluminum inside aNEMA 4 Outdoor Housing, w/PadlockableLatchesModel 4355–Die-cast aluminum inside aNEMA 4 Outdoor Housing, w/PadlockableLatches

AGENCY APPROVALS

FCC: Part 15.247 FCC approved

Underwriters Laboratories (UL)*: UL Approval for Class 1, Div. 2; GroupsA, B, C and D; hazardous locations

Factory Mutual (FM)*: FM Approval for Class 1, Div. 2; GroupsA, B, C and D; hazardous locations

* These certifications available on special orders.

FCC INFORMATION (USA) †

PART 90

Transmitter Model: E5M5LL2013

Channel Capacity: 1

Frequency Tolerance: ±0.00015%

Output Power :(Continuously Variable) 0.1 to 2 watts 0.1 to 5 watts

Necessary Bandwidth: 12.5 kHz 25 kHz

Emission Designators: F1D: 16K0 16K0F2D: 16K0 16K0F3D: 16K0 16K0

†Contact MDS for information on availability and governmental approvals in other countries.

OPTIONAL EQUIPMENT, ACCESSORIES and CERTIFICATIONS

The MDS 4310 Data Transceiver can be supplied with the following options. For informationon adding options to MDS radios, please contact the MDS Marketing Department.

Special Certifications

Some models of the MDS 4300 Series transceivers are available with either Factory Mutual(FM) or Underwriter’s Laboratory (UL) Approval for operation in Class I, Groups ABCD,


Division 2, hazardous locations. Please consult with the MDS Marketing Department forfurther information on these models.

1200 BPS Bell 202T Modem (Internal)—P/N 03-1815A01

The internal AFSK Bell 202T compatible modem is available for low speed datarequirements. It is used at slower standard speeds (30–1200 bps) and provides compatibilityin a radio system operating with non-MDS brand analog radios. A standard RS-232 C or TTLcompatible interface is provided through the radio’s INTERFACE (DB-25) connector.

4800 BPS Modem(Internal)—P/N 03-1831A01

This intermediate speed digital FSK interface (50–4800 bps asynchronous or 4800 bpssynchronous) can be used in any MDS 4300 Series remote radio. It is compatible with MDS4100 Series digital master station radios using this modulation technique.

A standard RS-232 or TTL compatible interface is provided through the radio’s INTERFACE(DB-25) connector.

9600 BPS Modem (Internal)—P/N 03-1833A01

The MDS internal 9600 bit per second (bps) FSK modem provides synchronous orasynchronous operation where high speed data exchanges are required. The modem iscompatible only with MDS 4100 Series digital master station radio systems operating at9600 bps. Available with RS-232 or TTL interface provided through the radio’s INTERFACE(DB-25) connector.

Audio Processing Module (Internal)—P/N 03-2301A01

The Audio Processing Module can be installed to support applications where no keyingcircuits are provided by a modem or remote terminal unit (RTU). The assembly senses thepresence of a tone on the transmit audio line and keys the transmitter. The VOX assemblyprovides for audio signal pre-emphasis and de-emphasis if needed. This option is mounted inthe Option 1 position on the transceiver’s main board. See Appendix J.

Order Wire Module (External)—P/N 02-1297A01

The Order Wire Module option is supplied as an external device that plugs into the radio’sINTERFACE (DB-25) connector. It can be used with a standard four-pin modular telephonehandset to provide a temporary voice link back to the master site for installation and testpurposes.

The order wire uses a voice-operated transmit (VOX) circuit to key the transmitter when theoperator speaks into the handset. Otherwise, normal operation of the remote transceivercontinues since the order wire option is installed in-line between the transceiver and theRTU/modem. See Appendix E.

Remote Maintenance Module (Internal)—P/N 03-1958A01

With a Remote Maintenance Module installed in the Option 2 slot, three levels of diagnosticsare available—Mode 1: Local Diagnostics, Mode 2: Advanced Diagnostics, and Mode 3:Remote Maintenance.



Remote Maintenance Module Continued

When Mode 1 (Local Diagnostics) is enabled, the following parameters are available:

• RSSI• Forward and reflected transmit power• VSWR• Transceiver internal ambient temperature• Phase lock loop (PLL) lock condition• Primary power and internally regulated voltages

This information is available locally through the HHT or a PC running MDS RemoteDiagnostic software (P/N 06-1972A01)

In Mode 2: Advanced Diagnostics mode, the diagnostics information available locally canalso be retrieved over-the-air through an MDS 4100 Series Master Station. The results aredisplayed on a personal computer running MDS 2000 Diagnostics and Control Systemsoftware.

Mode 3: Remote Maintenance provides the highest level of diagnostics capability. WhenRemote Maintenance is enabled, all of the above features are available plus local or over-the-air control of the following parameters:

• RF Power Output Setting• Frequency Offset• Modem Data Deviation

Certain hardware elements must be present in the Remote and Master Stations for the RemoteMaintenance feature to be enabled. Also, the transceiver must be properly programmed at thefactory, or in the field using the HHT or a PC. If you ordered your radio system with RemoteMaintenance capability, all of these elements will have been installed and tested at thefactory.

If Remote Maintenance is being added to the system, refer to the instructions included withthe upgrade kit for detailed installation procedures (Publication Number 05-2104A01).Consult the factory if you have questions regarding the capabilities of your existing system.

When using Remote Maintenance over the radio link, MDS 2000 Diagnostics and ControlSoftware is required. Refer to the instructions included with the software for detailedinstallation procedures (Publication Number 05-1919A01).

Hand-Held Terminal Kit (External)—P/N 02-1501A01

The Hand-Held Terminal (HHT) allows the service technician to make certain keyperformance checks on the transceiver without removing the radio from its mountingposition, and without the need for additional test equipment. In addition, the user canprogram the receive and transmit frequencies in the field, as well as other parameters.

Refer to Chapter 3 for information on connecting and using the HHT.

RS-232 to RS-422 Converter Assembly—P/N 01-2358A01

An optional RS-232 to RS-422 adapter plug (P/N 01-2358A01) is available to allow directconnection of an RS-422 circuit to the INTERFACE connector of a radio configured for RS-232operation. An RS-422 connection may be required if the length of the interface cable exceeds50 feet (15.24 meters).


TTL to RS-232 Converter Assembly—P/N 03-2223A01

An optional TTL to RS-232 converter is available to allow direct connection of RS-232equipment (such as an RTU or HHT) to a radio that has been configured for TTL operation.This unit connects between the transceiver INTERFACE connector and the external equipment,making the transceiver appear as an RS-232 device.

TOP COVER

OPTION 1—Modem PC Assembly orAudio Processing Module

OPTION 2—Remote Maintenance Moduleor Diagnostic & Loopback Module

INTERFACECONNECTOR

DETACHABLE & ADJUSTABLEMOUNTING BRACKETS (2)

TRANSCEIVERPC BOARD

BOTTOMCOVER

LED ANNUNCIATORDISPLAY

DC POWERINPUT

ANTENNA

COVER SCREWS

Figure 1-3. MDS 4310 Transceiver—Major Assemblies


This page intentionally blank

MDS 05-2415A01, Rev. A 2-1

CHAPTER 2—INSTALLATION

DANGERThe MDS 4310-HL Data Transceiver is approved for use inClass I, Groups ABCD, Division 2, Hazardous Locations.The installer of these transceivers MUST be familiar withhazardous location installation guidelines beforeinstallation or maintenance is begun. Do not begininstallation of or make external connections to this deviceunless the area is known to be non-hazardous.

Refer to Appendix H of this manual for further informationon the approved conditions under which the MDS 4310-HLcan be installed in hazardous locations.

OVERVIEW

The MDS 4310 data transceiver is designed to be part of a data communications system.Three critical objectives must be met during the installation—a good antenna system,adequate stable primary power and the correct interface between the transceiver and theexternal data equipment.

MDS 4310 transceivers are shipped with final test data sheets from the Manufacturing TestDepartment. The test data sheets contain radio hardware and software configurationinformation and actual performance measurements. Included in the data sheets are thetransmit and receive frequency (as measured), receive sensitivity, transmitter power outputand modulation characteristics, as well as pre-programmed loopback code. In most cases, thetransceiver requires no alignment during installation.

The following installation steps are for a typical installation.

1. Install the antenna transmission line, and preset the antenna heading.

2. Mount the transceiver vertically or horizontally on a stable surface.

3. Measure and install the primary power for the transceiver.

4. Verify that the unit serial number and loopback code are the same as found on thetest data sheet.

5. Verify that the transceiver’s operating frequencies are as listed on the operatinglicense. Check the license against the measured frequencies shown on the test datasheet.

6. Verify interface requirements and protocol—

If no modem is installed…

• Check the transmit audio input level.

• Check the receive audio output level.

• Check the keyline operating characteristics—Ground or +5 Vdc can be used tokey the transmitter. Make sure the correct pin is wired on the transceiver’sINTERFACE connector.

2-2 INSTALLATION MDS 05-2415A01, Rev. A

OVERVIEW Continued

If a modem is installed…

• Check the modem’s configuration switch, if applicable, to verify the modemconfiguration. (This applies to 4800 and 9600 bps modems only. Refer to tablesB-1 and C-1 for switch settings.) Is it compatible with the external dataequipment attached to the transceiver? The internal modem configuration isbased on data collected from the customer when the order was placed.

• Will the external data equipment provide asynchronous or synchronous data?(This applies to 4800 and 9600 bps modems only.)

• Will the external data equipment operate with Data Set Ready (DSR)continuously held high? Most data equipment will, and this line is tied highinside the radio.

• Request to Send (RTS) functions as transmitter keyline.

7. Connect the antenna, primary power and external interface equipment as required tothe transceiver.

8. Check the transceiver’s power output and antenna system VSWR (or reflectedpower).

9. Key the transmitter and optimize transmit and receive signals through refinement ofthe antenna heading.

10. Verify basic system operation by establishing data communications between theremote and the master stations.

This should complete the basic steps in the installation of the transceiver. More detailedinformation will follow in this chapter should the user experience difficulties or choose tomake more detailed operational checks.

SURFACE MOUNTING

Using the supplied bracket, the MDS 4310 Data Transceiver can be mounted in any positioninside heated or unheated equipment buildings. For outdoor mounting, the unit must bemounted in either a customer-supplied weatherproof housing or the MDS 4350/MDS 4355packaged enclosure. The MDS 4310 die cast package withstands casual water, such as drips,occasional spills, or condensation, but it is not suitable for continuous exposure to rain orwind-driven moisture.

There are two mounting footprints that can be used. Choose the one that best suits yourinstallation situation. See Figures 2-1 and 2-2 for details and dimensions.

NOTEThe mounting brackets must be fastened to the transceiverhousing with #6-32 x 5/16 inch screws. Longer screws willpenetrate the housing and damage the main printed circuitboard.

MDS 05-2415A01, Rev. A INSTALLATION 2-3

To install the unit:

1. Choose a location to allow easy access to the fasteners so that the entire unit can bereadily removed for service or replacement, yet allows viewing of the LEDindicators on the front of the case.

2. Fasten the brackets to the mounting surface with a 1/4 inches (M6) bolt, screw, or lagscrew (fasteners not provided) through the four holes in the mounting bracket.

3. If mounting surface is uneven, use three fasteners instead of four to prevent warpingof the mounting bracket.

AAAAAAAAAAAAAA

IN T E R F A C E

KL TX RX

DC IN

D C IN

A N T E N N A

OL

2.0

in.

51 m

m

2.25

in.

57 m

m

5.6 inches143 mm

Figure 2-1. Mounting Dimensions—Front View

MOUNT BRACKETS WITH THESE TWO HOLES FOR ALTERNATE MOUNTING

6.75 inches171 mm

8.5 inches216 mm

7.25

in

ches

184

mm

2.75

in.

70 m

m

USE ONLY #6-32 x 5/16 INCH SCREWS

Figure 2-2. Mounting Dimensions—Bottom View


EXTERNAL CONNECTIONS

The following section describes how to connect external equipment to the transceiver intypical installations. These recommendations may not be appropriate for all locations; localelectric wiring or fire codes may prescribe unique standards. The US National ElectricalCode is commonly the basis for local wiring guidelines and is recommended in the absenceof local standards.

DANGERThe MDS 4310-HL Data Transceiver is approved for use inClass I, Groups ABCD, Division 2, Hazardous Locations.The installer of these transceivers MUST be familiar withhazardous location installation guidelines before any instal-lation or maintenance is begun. Do not begin installation ofor make external connections to this device unless the areais known to be non-hazardous.


ANTENNA Connector

The ANTENNA Connector on the front panel of the MDS 4310 is the RF connector. See Figure2-1. It is an industry standard female type “N” connector and mates with a standard type “N”male connector, such as Amphenol 3900 (MIL Type UG-21) for RG-8 cable.

The exact mating connector type depends on the cable used. If large diameter rigid or semi-rigid coaxial cable is used for the feedline (see Antenna and Feedlines section), use a shortlength of RG-8 or RG-214/U cable between the transceiver and the feedline. A three footsection of RG-214/U cable with connectors at both ends (P/N 19-1323A01) is available fromMDS. This flexible interface eliminates tight bends in the feedline and reduces bending,mechanical stress on the feedline and connectors.

+13.8 DC (Primary Power) Connector

The radio can be powered from +13.8 Vdc power source connected through J2 on thetransceiver’s front panel. A custom power cable with an integral fuse and a molded matingconnector is provided with the radio. The lead with the integral fuse is the positive + line andthe lead with no fuse is the negative – line.

This power cable has an in-line fuse rating of three amperes (3A); do not use a substitutecable without providing some type of external current limiting (fuse) protection for the radio.

INTERFACE Connector

On the left side of the front panel is the INTERFACE connector, J1, consisting of a standard 25-pin female “D” style connector. It mates with male connectors of the same series, such as theITT CANNON DB-25-P. These connectors are manufactured by many firms and areavailable from distributors or from most retail electronics stores.


NOTEDo not use a full RS-232 cable for connection to the INTERFACEconnector. Cross-coupling between wires in the cable can causeimproper operation. Use only the pins required for theapplication. (Refer also to Note 2 in Table 2-1.)

ANTENNA

INTERFACE

TD IN RD

TR MR CD13.8 VDC+

–

DATA AND MODULATION INTERFACE

DC POWER INPUT

13.8 VDC

ANTENNA CONNECTOR & TRANSMISSION LINE

Figure 2-3. External Connections

Radios without internal modems…

The INTERFACE connector allows a unbalanced 600Ω voice frequency interface to the radiowith additional pins for transmitter keying (PTT), alarm, and diagnostic indications.

When an optional MDS internal modem is installed…

The INTERFACE connector allows a standard RS-232 interface. The full handshakeimplemented includes TXD, RXD, RTS, CTS, and DCD. DSR is true whenever the radio andmodem are powered up, and the transmitter is automatically keyed when RTS goes high.CTS is raised after the programmable delay (factory default is 10 ms), to allow time for thesynthesizer to change frequency and for the receiver at the other end of the link to unsquelch.This time can be modified by the user to suit specific system timing requirements with theHHT.

When equipped with an optional internal modem, the MDS 4310 “SMART” DataTransceiver interfaces directly to any data terminal or RTU that supports the Bell 202,RS-232 format. This considerably simplifies installation, since the levels between the radioand modem can be preset at the factory, eliminating field measurements or adjustments. PTTcontrol and delay are handled automatically by the radio with the RTS/CTS handshake. Evenwith the internal modem, the MDS 4310 “SMART” Data Transceiver allows programmingand diagnostic information to be accessed without disassembly of the transceiver enclosure.


When using an internal modem, other pin functions of the DB-25 INTERFACE connector, suchas PTT, Receive Audio, Transmit Audio and RSSI are still active and should normally be leftopen (unterminated). Connecting these pins to a computer terminal that also uses these pinsfor auxiliary connections can cause improper operation.

Pin connections for the transceiver’s INTERFACE connector are summarized in Table 2-1 andare described in greater detail later in this chapter.

NOTEWhen using the TTL interface option, external 1 kΩ (1/8 W)pull-up resistors are required between J1 Pins 2, 3, 4, 5 & 6 andthe logic source in the remote terminal unit (RTU).

Table 2-1. DB-25 Interface Connector Pin Functions13 1

25 14

Viewed from Outside or from Plug’s Solder Cups

Pin Number and Function Pin Number and Function

1. Shield

2. Transmit Data In (TXD)*

3. Received Data Out (RXD)

4. Request-To-Send (RTS)*

5. Clear-To-Send (CTS)

6. Data Set Ready (DSR)

7. Signal Ground

8. Data Carrier Detect (DCD)

9. Transmit Audio Input*

10. Receiver Unsquelched Sense

11. Receiver Filtered Audio Output

12. Radio Disable*

13. Transmit Audio Output

14. Push-To-Talk (PTT)*

15. Transmit Clock (TC)

16. Push-To-Talk (PTT)*

17. Receive Clock (RC)*

18. +13 Vdc

19. +8 Vdc

20. No Connection

21. Received Signal Strength Indicator(RSSI)

22. Loopback Test–Receive Audio Input*(For local testing of loopback DTMFdecoder)

23. Open Diagnostics

24. External Transmit Clock (ETC)*

25. Out-of-Lock Alarm

* Input


NOTES For Table 2-1

1. The radio is configured as DCE (data circuit-terminating equipment), as opposed toDTE (data terminal equipment).

2. When using an internal modem, other pin functions of the DB-25 INTERFACEconnector, such as PTT, Receive Audio, Transmit Audio and RSSI, are still activeand should normally be left open (unterminated). Connecting these pins to anexternal device such as a computer, RTU or PLC that also uses these pins forauxiliary connections can cause improper operation. The use of an interface cablethat connects only the required pins is recommended.

3. Pins 1-8 are standard RS-232-C lines.

INTERFACE Connector Pin Functional Descriptions

The following description covers the INTERFACE connector pin functions. The pindescriptions are identical whether or not a modem is installed.

PIN 1: Shield

Connected to ground (negative supply potential) at the radio PC board.

PIN 2: TXD—Transmitted Data Input

without modem

This pin is connected to the data input port of the microcontroller and is used withan external programming terminal.

with internal modem

As above, this pin is also connected to the data input port (TXD) of the internalmodem and is RS-232 compatible.

PIN 3: RXD—Received Data Output

without modem

This pin is connected to the data output port of the microcontroller and is alsoused with an external programming terminal.

with internal modem

As above, this pin also provides an RS-232 compatible output of data received bymodem.

PIN 4: RTS—Request-To-Send Input

with internal modem

An RS-232 compatible input to modem which keys transmitter when RTS is atlogic “high”.

PIN 5: CTS—Clear-To-Send Output

with internal modem

An RS-232 compatible output to external RTU or terminal, which goes “high”after the pre-programmed CTS delay time has elapsed.


PIN 6: DSR—Data Set Ready

Provides a + 8 Vdc DSR signal to external terminal through a 1 kΩ resistor.

PIN 7: Signal Ground

Connected to ground (negative supply potential) at the radio PC board.

PIN 8: DCD—Data Carrier Detect

with internal modem

Provides an RS-232 compatible output. Goes “high” when the modem detects acarrier from the master station.

PIN 9: Transmit Audio Input

without modem

The transmit audio input pin is normally connected to the audio output from theassociated modem or RTU. The input impedance is 600 ohms, and the deviation isfactory set so that an input level of –10 dBm produces a nominal transmitterdeviation of 2.5 kHz. This is the correct deviation level for most 12.5 kHz systemsand will also provide satisfactory service in most 25 kHz systems.

The deviation can be adjusted to fulfill the requirements of equipment using audiolevels other than –10 dBm. See Chapter 3—Field Tests And Adjustments fordetailed alignment procedures.

If the distance to the modem or RTU is greater than five feet (1.52 meters), use atwisted pair of conductors to connect the transmit audio circuit. Connect one endof the pair to the audio output terminals of the modem or RTU and the other endto Pin 9 and Pin 7 of the INTERFACE connector.

with internal modem

The order wire audio output appears on Pin 9 whenever the external order wireassembly is connected. Transmit audio from the modem is cut-off internallywithin the transceiver when order wire is in use. This applies only to PTT. PTTwill not cut off the internal modem output.

PIN 10: Receiver Unsquelched Sense

This pin is not used in typical installations, but it is available as a convenience forspecial applications. It is pulled up to +8 Vdc through a 1 kΩ resistor wheneverthe receiver squelch is open, and pulled down to less than 1 Vdc when the squelchis closed. The output resistance of 1 kΩ should be considered when interfacingexternal equipment.

PIN 11: Receiver Filtered Audio Output—Line Level

This is the received audio output of the transceiver and is connected to the audioinput of the external modem or RTU. It will drive a 600 ohm load; the outputlevel is factory set to –10 dBm into 600 ohms for rated system deviation of2.5 kHz on the received signal. Audio from the receiver discriminator is passedthrough a 3 kHz low-pass filter before it reaches this pin. This response is idealfor most external modems because it eliminates high frequency noise that candegrade the bit error rate performance of the modem. The audio response is nearlyflat between 50 and 3000 Hz (no de-emphasis).


PIN 11: Receiver Filtered Audio Output—Line Level (Continued)

If the distance to the modem or RTU is greater than five feet (1.52 meters), use atwisted pair of conductors to make the connection. Connect one end of the pair tothe audio input terminals of the modem or RTU and the other end to pins 11 and 7of the INTERFACE connector.

PIN 12: Radio Disable

A ground on this point will totally disable the radio, including transmit, receive,modem and diagnostic functions. The pin controls the +8 Vdc used by alltransceiver circuits. The I N LED is lit when Pin 12 of the INTERFACE connector isgrounded. This input can be used to reduce power consumption during periods ofnon-use.

PIN 13: Transmitted Audio Output

with internal modem

This is the audio output of the modulator IC in the modem and is provided for testpurposes.

PIN 14: PTT (Push-To-Talk )

This is one of two transmitter keying (PTT) inputs. The PTT input is normally atground. When this pin is pulled up to greater than 4 volts, the transmitter is keyed;when the pin is at less than one volt (“open” circuit), the transmitter is off and thereceiver is active. See pin 16 description.

PIN 15: TC—Transmit Clock

This pin is used only on applications requiring a synchronous interface. This pinprovides a signal to clock transmit data bits out of the terminal connected to theradio. The Transmit Clock signal is compatible only with RS-232 interfaces.

PIN 16: Push-To-Talk (PTT)

This is an active-low PTT input, pin 16, it acts in the opposite way from pin 14; itis normally at 5 Vdc. When it is pulled down to less than one volt, the transmitteris keyed; when it is greater than 3 volts (“open” circuit), the transmitter is off.

PIN 17: RC—Receive Clock

This pin is used only on applications requiring a synchronous interface. This pinprovides a clock signal to clock receive data bits from the radio to the terminalconnected to the radio. The Receive Clock signal is compatible only with RS-232interfaces.

PIN 18: +13 Vdc Unregulated Source

This pin provides a convenient source of unregulated 13 Vdc at 0.5 A forpowering external low current equipment. This connection provides the primarypower to the radio with no regulation. Excessive drain on this connection willblow fuse, F1, on the transceiver board.


PIN 19: +8 Vdc Regulated Source

This pin provides a convenient source of regulated 8 Vdc at 10 mA for poweringexternal equipment.

PIN 20: No Connection

PIN 21: RSSI (Received Signal Strength Indicator)

A received signal strength indicator (RSSI) output is provided on this pin to aid insteering antennas and monitoring changes in relative signal strength of receivedsignals.

Figure 2-4 is a graph plotting the typical RSSI voltage versus signal input. Whenmeasured with a DVM, the accuracy of the RSSI is approximately ± 10 dBm. TheRSSI will be within 3 dBm when displayed on the HHT.

0

0.5

1

1.5

2

2.5

3

3.5

4

–140

–120

–100 –8

0–6

0–4

0

DC

VO

LTS

SIGNAL LEVEL (dBm)

Figure 2-4. Received Signal Strength Indicator Calibration Chart (Typical)

PIN 22: Loopback Test—Receive Audio Input

A direct input to the loopback and diagnostics module’s DTMF decoder. Can beused with external DTMF encoder to simulate a polling request from a masterstation. Nominal input signal level required: –10 dBm.

PIN 23: Open Diagnostics

A low on this input opens the diagnostics channel. If the terminal cable provides aground for this pin the diagnostics channel automatically opens. If this pin is notgrounded, the OPEN command is required from the HHT or terminal to allowdiagnostics and control functions of the transceiver.


PIN 24: ETC—External Transmit Clock

This pin is used only on applications requiring a synchronous interface with anexternal device controlling the timing of the transmitted bits. The most commonapplication of this pin is where the MDS 4310 is connected to an external highspeed modem. In this case, a cross-over (“null-modem”) cable is required thatconnects Pin 17 (RC) from one modem to Pin 24 (ETC) of the other, and viceversa. In most instances, timing is controlled by the internal clock inside the MDS4310 (from Pin 15), and Pin 24 should be left open. The External Transmit Clocksignal is compatible only with RS-232 interfaces.

PIN 25: Out-of-Lock Alarm

A logic low (≤ 0.5 volts) on this pin indicates normal operation. A logic high(≥ 4 volts) indicates a failure in the main phase lock loop or TCXO, or a trans-mitter time-out condition. A logic high also causes the transmitter and receiver tobe shut down. This pin can be used as an alarm output, if the internal seriesresistance of 1 kΩ is considered when designing an external interface circuit.

FRONT PANEL INDICATORS

The radio is supplied with a set of six light emitting diode indicators (LEDs) that provideinformation on the status of key operating functions. The indicators can be disabled if thejumper on the transceiver’s main board at J11, pins 2 & 2 is removed. With the pins bridged,the display is enabled. There are two versions of the plastic label for the front panel of theradio—one for radios without a modem installed (See Table 2-2), and one for radios withinternal modems (See Table 2-3).

Table 2-2. External IndicatorsPWR TX CD

RTS TXD RXD

LED FUNCTION INDICATES

PWR Power Indicator Primary power is applied and is greater than 10Vdc.

If this indicator is flashing, the VCO is out-of-lock.All transmit and receive functions are disabled.

TX Transmit The transmitter is keyed and is on-the-air

CD Carrier Detect Receiver detects an on-channel signal and thesquelch is open.

RTS Request To Send The RTU is asserting a Request To Send signal.

TXD Transmit Data Reflects the current state of the Transmit Dataline from the Remote Terminal Unit (RTU).

LED OFF=0, LED ON=1

RXD Receive Data Reflects the current state of the Receive Data linefrom the transceiver internal modem.

LED OFF=0, LED ON=1


TRANSCEIVER CONFIGURATION JUMPERS

The 4310 Transceiver has three jumper blocks that configure the transceiver. The followingsections describe the use and function of these jumpers.

J11—TTL/RS-232 and LED Enable Jumpers

Jumper J11 configures two functions; the front panel LEDs and interface signal levels. SeeFigure 2-5 and Table 2-4 for jumper details.

With J11 Pins 1–2 jumpered, the INTERFACE connector communications pulses are 0 or 5Vdcand are commonly referred to as TTL. With no shunt across J11 Pins 1–2, U31 is enabledproviding standard + and -12 Vdc signals on the RS-232 compatible signals available at theINTERFACE connector. A shunt across J11 Pins 1–2 disables U31 which is the RS-232 linedriver/receiver IC. With U31 disabled, the signal lines are not converted to RS-232 12Vdclevels.

The function of J11 pins 3–4 allows the disabling of the LED indicators on the transceiverfront panel. Disabling the LEDs allows less current consumption in solar-poweredinstallations and other current sensitive installations. With J11 pins 3–4 jumpered the LEDdriver IC is enabled and the LEDs function. Conversely, when the jumper is removed fromJ11 pins 3–4 the LED driver IC is disabled and the LEDs do not function.

CAUTIONTo prevent possible damage to the interface circuitry,disconnect primary power and the INTERFACE connectorbefore changing jumpers. J11 Pins 1-2 must be shunted ifany of the input/output lines are to be operated at TTL levels.Failure to do so can damage the transceiver or RTU or maycause intermittent operation.

J14RX AUDIO

NORMAL/INVERT

J1EXTERNALINTERFACE

TCXOFREQUENCY ADJUSTMENTJ11

RS–232 DISABLELED ENABLE

J16FULL DUPLEXINTERFACE

3

4

1

2

3 4

1 2

123

PRINTED CIRCUIT BOARD MODEL

LABEL

Figure 2-5. Location of Configuration Jumpers


Table 2-4. J11–External Interface TTL/RS-232and Front Panel LED Configuration

LOCATION SHUNTED OPEN

1–2 TTL Enabled RS-232 Converter Enabled*

3–4 Front Panel LEDs Enabled* Front Panel LEDs Disabled

* Standard factory configuration

J14—Receiver Audio Output Phase

The receiver audio output phase can be shifted by 180 degrees (inverted) through the use of aprogrammable jumper on the transceiver’s motherboard at J14—Audio Normal/Inverted. Thetable below shows the possible positions of the jumpers. See Figure 2-5 for the boardlocation of the jumper and Figure 2-6 for details. Do not move this jumper from its factorysetting without first consulting MDS Systems Engineering.

Table 2-5. J14 Receiver Audio Output Normal/Inverted

LOCATION SHUNTED

1–2 Normal Audio*

2–3 Inverted Audio

* Standard factory configuration

123

J14

Figure 2-6. Detail of Configuration Jumpers—J14

J16—Full Duplex Option Connector

J16 Pins 1–2 and J16 Pins 3–4 must be jumpered for normal remote operation. The FullDuplex Option Connector is used only when the MDS 4310 is paired with another MDS 4310transceiver for full duplex operation. Do not move these jumpers from the factory settingswithout first consulting MDS Systems Engineering.

MODEMS—GENERAL

Introduction

MDS offers three modem interfaces for the MDS 4310 Data Transceiver operating at1200, 4800 and 9600 bits per second. Details on each modem are provided in separateappendices at the end of this manual. Any one model of the modems can be installed in


the transceiver or in the MDS 4350/MDS 4355 packaged system, provided acomplementary Interface/Utility board is installed in the MDS 4350/MDS 4355.

The following is a general discussion of modem interface signaling.

The Role of the Modem

The purpose of the modem is to convert RS-232 data passing through the externalINTERFACE connector into digital signals that will modulate the transmitter, and to convertsignals recovered from incoming radio signals into RS-232 data. The modem is alsoresponsible for accepting RTS (Request To Send) from the INTERFACE connector and foracknowledging transmitter operation with a CTS (Clear To Send) signal through theINTERFACE connector to the attached equipment.

RTS and CTS Signals

When RTS on the INTERFACE connector goes high, the transmitter is keyed by the RTSline connected to the modem. Whenever the transmitter is keyed, a timer is started thatwill, after a programmed time period, raise the CTS line at the INTERFACE connector. ThisCTS time delay allows time for the transceiver’s transmitter and the master’s modemcircuitry to stabilize before data can be sent to the master station. CTS is programmablein 1 ms increments within the range of 5 to 255 ms. MDS recommends a minimum of 10ms of CTS delay for optimum system performance. Thus, 10 ms is the factory default.

When RTS goes low, the transmitter is unkeyed and CTS is set to low.

DCD Signal

When the squelch circuit in the receiver senses the presence of a carrier, the DCD linegoes high. When the squelch circuit in the receiver senses the lack of a carrier, the RXDoutput is forced to a “Mark” condition and the DCD signal is set low. RXD and DCD aresignals on the INTERFACE connector.

POWER REQUIREMENTS

The MDS 4310 Transceiver can be powered from any source with a nominal terminal voltagebetween 12 and 15 volts direct current and capable of supplying a minimum of 2.5 amperes.

NOTEUnder no circumstances should the nominal supply voltagedrop below 10.5 volts or rise above 16.5 volts. The supply mustbe sufficiently regulated to limit any change in its outputvoltage to one volt or less when the transceiver alternatesbetween transmit and receive.

The power output is factory adjusted for 5.0 watts at 13.8 volts. If the actual supply voltage isnot 13.8 volts under load, the transceiver’s power output should be adjusted to 5.0 wattsbefore the unit is put into service.

One approach to powering the MDS 4310 Transceiver from a 120 Vac source and providingfor backup power during power outages is to float charge a 12 volt storage battery from aregulated 13.8 Vdc power supply. The radio can then be connected directly across the batteryterminals. The power supply should be equipped with current limiting to protect it in theevent the battery becomes deeply discharged during a long outage.


The battery used should be designed for deep discharge service. Such batteries are availablefrom industrial battery distributors and retail outlets, where they are sold as power sources forrecreational vehicles or for electric trolling motors for sport fishing.

ANTENNAS AND FEEDLINES

Antenna Selection and MountingA directional Yagi or corner reflector antenna is required by the FCC for use on all remotestations to minimize interference to and from nearby systems. Good antennas of this type areavailable from a number of manufacturers. Some 450 MHz directional antennas are listedbelow.

Manufacturer Model Number

Antenna Specialists ----------- ASP-604Sinclair-------------------------- SRL-307

SRL-307RC-HDSRL-350

Telewave ----------------------- ANT450Y10Scala ---------------------------- CA5-450

CA7-460CL-400RA5-450

The antenna manufacturer’s recommended mounting configuration for a particular antennamust be strictly followed. Use the proper mounting hardware and bracket to ensure a securemounting arrangement with minimal pattern distortion. Any metallic object close to theantenna will distort the radiation pattern and, in severe cases, detune the antenna enough tocause a high VSWR on the antenna feedline.

CAUTIONStrong fields near the antenna can interfere with the operationof low level RTU circuits and change the reported values ofthe parameters being monitored. Also, objects in the nearfield of the antenna can increase VSWR and distort theantenna pattern, resulting in reduced system performance.The antenna should always be mounted at least 10 feet(≈3 meters) from the radio, RTU, sensors, and othercomponents of the system.

When installing the antenna:1. Mount the antenna in a clear space as far as possible from obstructions such as

buildings, metal objects, foliage, etc. The importance of this matter cannot beoverstated.

2. Make sure that the field is clear in the direction of the master station.3. Orient the antenna in the direction of the master station if the direction is accurately

known. Preferably, monitor the signal from the master station with a DC voltmeterconnected to the radio’s RSSI pin (Pin 21 on the DB-25 connector), and rotate theantenna for maximum indication.


NOTEA Yagi antenna can be oriented for either horizontal or verticalpolarization. All systems using a gain type omni-directionalantenna at the master station employ vertical polarization of thesignal; therefore the remote antenna must also be verticallyoriented, with its elements perpendicular to the earth’s surface.If the antenna is mounted with its elements parallel to theground (horizontal polarization), the received signal strengthcan be reduced by 20 dB or more.

Feedline Selection

Choice of correct feedline (the coaxial cable that connects the radio to the antenna) for theparticular circumstances of each installation is very important; poor cables can seriouslydegrade system performance and low loss cables, while superior, can be quite expensive.

For example, 100 feet (30.48 meters) of RG-58A/U cable (commonly used for low frequencyoperation) has an insertion loss of 13 dB at 450 MHz. A 5 watt transmitter operating intosuch a feedline would produce only 250 milliwatts at the antenna; a similar loss in receiversensitivity would result and no amount of gain at the receiver can recover the signal lost inthe feedline. On the other hand, a 100 foot (30.48 meters) length of 1 5/8 inch HELIAX has aloss of 0.55 dB at the same frequency, but its cost is many times greater than RG-58A/U.

In any point-to-multipoint system there will be a distribution of remote stations, with somecloser to the master station than others. For the close-in units, feedline loss is not asimportant, and 6 dB or more of loss can be acceptable. For the furthest-out remote units, eachdecibel of loss directly affects bit error rate and the amount of time the system misses pollsdue to fading. Here, it is good practice to keep feedline losses well under 3 dB, with a targetloss of only 1 dB.

NOTEFor each 3 dB of feedline loss, half the transmitter power is lostand twice the receiver signal is needed to produce the same biterror rate.

RG-8 or RG-214/U cable is widely available and inexpensive. It is suitable for close-inremote units or for those installations with short feedlines. For longer feedlines and lowerlosses, HELIAX® or similar cable is a good choice. Table 2-6 shows the maximum length ofvarious types of cable that can be used to give 1, 3, 6 or 9 dB feedline loss.

Table 2-6. Signal Loss versus Cable Length and Type

CABLE TYPELENGTH IN FEET (AND METERS)

TO PRODUCE INDICATED LOSS AT 450 MHz

1 dB 3 dB 6 dB 9 dB

RG-8 18 (5.49) 54 (16.46) 109 (33.22) 163 (49.68)

1/2 inch Foam HELIAX 66 (20.12) 199 (60.66) 397 (121.01) 596 (181.66)

7/8 inch Foam HELIAX 120 (36.58) 260 (79.25) 719 (219.15) 1079 (328.88)

1-5/8 inch Foam HELIAX 194 (59.13) 582 (177.39) 1165 (355.09) 1747 (532.49)


Feedline Installation

It is absolutely essential that the feedline connectors be installed in accordance with themanufacturers’ instructions for the particular type of connector used. Also, any specialtooling required for mounting the connectors must be used, to ensure maximum mechanicaland electrical reliability. Be careful to check that the finished center pin dimensions arewithin specifications to prevent damage to mating connectors when the two are joined.

Connectors that are exposed to outdoor environments must be sealed to prevent moisturebuildup in the connector. In extreme cases, rainwater can get into a connector and fill theentire feedline with water, creating a high loss cable that will have to be replaced. There areseveral good methods for weatherproofing these outside connections; consult the cable orconnector manufacturer for their recommended materials and procedures.

The feedline itself must also be installed carefully to prevent short-term or long-term damage.Short-term damage can consist of kinking, twisting or excessive elongation of the cableduring installation. Harmful long-term effects could be due to improper connector sealing, abend that is too tight, insufficient strain relief on the cable when mounted on the tower, orexcessive flexing and vibration due to wind.


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MDS 05-2415A01, Rev. A 3-1

CHAPTER 3PROGRAMMING AND DIAGNOSTICS

INTRODUCTION

A significant feature of the 4310 Transceiver is the ability to accomplish many radioprogramming and diagnostic tasks through software commands issued from a Hand-HeldTerminal (HHT).

Software control of the transceiver allows measurement and adjustment without removing thetop cover. In addition, when the Remote Maintenance feature is installed and enabled, manyof the same programming and diagnostic functions can be accessed over the RF channel,thereby eliminating the need to travel to an installation site to perform minor checks andadjustments.

This chapter explains how to connect the HHT to the transceiver, open the DiagnosticsChannel, and enter commands on the HHT keyboard. Step by step examples are used tosupport the programming and diagnostic instructions.

Table 3-2 includes a complete list of HHT commands. Experienced users may wish to referdirectly to the table when programming or diagnosing the transceiver.

TERMINAL CONNECTION AND STARTUP

Connecting the HHT to the transceiver is simple, since the HHT interface cable includes aDB-25 adapter plug that allows direct connection to the radio’s INTERFACE connector.

NOTEBefore connecting the HHT to the transceiver, verify the radiois connected to a continuous +13.8 Vdc supply. (Most often thetransceiver is powered continuously, but some solar-poweredsystems operate on an intermittent basis, making an alternatepower source mandatory for testing.) MDS also recommendsusing a dummy load on the A N T E N N A connector of thetransceiver during all testing. This prevents accidentalinterference to the rest of the radio system.

To connect and startup the HHT, follow these steps:

1. Remove the RTU interface cable from the INTERFACE connector on the transceiverand set it aside. This step is not required for the MDS 4355 packaged system.

2. Plug the HHT into the INTERFACE connector as shown in Figure 3-1. If it is a MDS4355 packaged system, plug the HHT into J3 of the Interface/Utility assembly asshown in Figure 3-2.

3. Press and hold the ENTER key as the HHT runs through its self-check, a click will beheard from the HHT, then release the ENTER key.

3-2 PROGRAMMING AND DIAGNOSTICS MDS 05-2415A01, Rev. A

4. This completes the HHT startup procedure. After a five second “quiet time” (noreception of radio signals), the Diagnostics Channel may be opened as outlinedbelow.

ZCTRLU

+

–K

*

F/

AF1

V,

Q#

)G

(B

F2

SHIFT

ESCW

=R

7M

4H

1C

F3

BKSP

X0

S8

N5

I2

DF4

SPACE

Y

T9

O6

3E

F5

ENTER

J

L

P

ANTENNA

INTERFACE

TD IN RD

TR MR CD13.8 VDC+

–

Figure 3-1. Hand-Held Terminal Connected to the MDS 4310 Transceiver

F5

F4

F3

J3

R28J1

J625

SW1 J5

R10

R9

F1

F2

T1

4

5

6

3

2

1

T2

4

5

6

3

2

1

V3

V2

V1

CR7

TB

2T

B1

J4

J7

RS

-232

INT

ER

FAC

E

2

3

1

TB

2

J3

Figure 3-2. MDS 4355 Packaged Transceiver

MDS 05-2415A01, Rev. A PROGRAMMING AND DIAGNOSTICS 3-3

Special Instructions for Radios Configured as TTL

In most cases, an HHT can be plugged directly into the radio’sINTERFACE connector and used immediately. However, in some cases,the INTERFACE connector may have been configured for TTL operation(as opposed to the more common RS-232 format) using the radio’s J11jumper.

If you are unsure of which configuration you have, look at J11 on thetransceiver’s motherboard. In an RS-232 radio, J11 pins 1-2 will be empty(open).

If your radio is configured for TTL, an optional TTL to RS-232 adapter plugis available from MDS (P/N 03-2223A01) to allow connection of the HHTor other RS-232 equipment, making the transceiver appear as an RS-232device. Contact MDS for ordering information.

If the TTL to RS-232 adapter plug is not available, it is also possible totemporarily reconfigure the INTERFACE connector for RS-232 operationby removing the jumper on J11 pins 1–2. (See Table 2-4 for proper jumperplacement.) When testing is complete, J11 can be restored to its TTLconfiguration.

NOTE

Plugging an HHT or a PC into a transceiver configured for TTL signalingwill key the radio transmitter, and will not allow terminal operation.However, no damage will be done to the terminal or radio.

Opening The Diagnostic Channel

The diagnostic channel between the HHT and the transceiver is automatically opened when aHHT is connected to the transceiver. However, if an older HHT or transceiver is being used,it must be opened before HHT functions can be performed. To manually open the diagnosticchannel when using older HHTs or transceivers, follow the steps below:

1. After the HHT has completed its self-check, look for a solid flashing cursor on itsdisplay. This indicates that the Diagnostic Channel is closed and that the HHT isready to accept the OPEN command.

2. Press ENTER . Wait at least five seconds to satisfy the required “quiet time.”

3. After the five second quiet time, type OPEN + ENTER .

4. When the channel opens, the message "DIAGNOSTICS IS OPEN" appears.

NOTEIf the Diagnostics Channel does not open the first time, wait atleast 5 seconds before trying again.

When the Diagnostics Channel is open, any keyboard entry is echoed by the transceiver andappears on the HHT display. In radios that have a modem installed, the received data (RD)and the transmit data (TD) LEDs will flash to indicate the exchange of information betweenthe HHT and the radio’s microcontroller.

The radio’s microcontroller and the modem share the communications lines connected to theINTERFACE connector. In this way, no data will be passed through the modem to thetransmitted signal when the INTERFACE connector is connected to the HHT and thediagnostics channel is open.


CAPABILITIES OF THE HHT

With the HHT properly connected to the transceiver’s DB-25 INTERFACE connector, thefollowing can be performed.

• Review operating parameters and diagnostic information

• Set the operating parameters of the radio

• Program user information

All of these tasks can be performed with the radio mounted in its final operating positionwithout the need for removing the top cover of the transceiver enclosure.

Review Operating Parameters and Diagnostic Information

The user can review the current settings of various operating parameters of the radio, as wellas monitor several key test points in the radio. These parameters include:

• Radio model number, serial number and date of manufacture

• Transmit and Receive Frequencies

• Supply voltage, Lock voltage and Regulator voltage

• Transmit Forward Power Output

• Antenna Voltage Standing Wave Ratio—VSWR

• Time-out Timer Length

• Squelch Tail Eliminator Status*

• RTS/CTS Delay Interval

• Soft Carrier Dekey**

• Push-To-Talk Delay†

• Temperature Inside Radio Housing

The values of diagnostic parameters (voltages, signal strength, etc.) are updated once everysecond to allow the technician to make adjustments while observing the HHT display. In thisway, you do not need to invoke the diagnostic command each time a control is moved.

* The Squelch Tail Eliminator circuit senses the end of the incoming data message (bydetecting the loss of the 1200 Hz mark/idle tone), and shutting off the receiver’saudio before the received carrier drops. In this way, the receiver does notmisinterpret the squelch tail noise burst as data. The Squelch Tail Eliminator featureis only available on analog radios.

** The Soft Carrier Dekey feature keeps the transmitter keyed for a short period(typically 4 ms or less) after the RTU has sent the last data bit to the transceiver. Thisallows the modem time to process and transmit all of the characters in each message,and reduces the possibility of framing or BCH (cyclic frames) errors.

† Push-to-Talk delay inserts a programmed delay (typically 5 to 31 ms) between thetime the RTS or PTT line is asserted and when the transmitter is actuated. This isdone to prevent carrier overlap (two stations transmitting at once) and other timingproblems that could otherwise occur in some systems, especially those withrepeaters. Carrier overlap causes lost or corrupted data.


Setting the Operating Parameters

The user can select and set several of the operating parameters of the radio. These parametersinclude:

• Transmit Frequency

• Receive Frequency

• Time-out Timer Length

• Enable or Disable Time-out Timer

• Squelch Tail Eliminator Status

• RTS/CTS Delay Interval

• Soft Carrier Dekey Delay Length

• Loopback Code

• Push-To-Talk Delay

Program User Information

The user can program information into the radio that is specific to the individual user. Thisinformation includes:

• Owner’s Name (20 characters total)

• Owner’s Specific Message(For example—assigned location or date unit placed in service. 27 characters total).

This information is stored in EEPROM, and will remain programmed in the radio until newinformation is entered.

USING THE HAND-HELD TERMINAL— Basic Operations

Command Syntax

The proper procedure for using the review commands is the command, followed by an ENTER

keystroke. For the programming commands, the appropriate command is followed by a SPACE

keystroke, followed by the information or values, then ENTER . See Programming Examplesfor further information.

Shift Key

The shift key is used to access the numbers on the keyboard of the HHT. Pressing the SHIFT

key once locks the keyboard into the upper level character set; the SHIFT key has to bepressed again to return to the main character (alphabet) set. Exception: Pressing the ENTER

key automatically returns the keyboard to the main character set.

Backspace (BKSP) Key

The Backspace key BKSP can be used to edit information or commands as they are beingentered with the keyboard. The backspace key works only when the SHIFT key has thealphabet selected.


Error Messages

Listed below are common error messages that may be encountered when using the HHT.

"INCORRECT ENTRY"Data was entered in a wrong format, or wrong number of digits.

"COMMAND ENTRY ERROR"Command improperly entered, or an invalid command was tried.

"INCORRECT FREQUENCY ENTRY"Last digit of frequency was omitted, or frequency entered was out of range.

"DIAGNOSTICS NOT INSTALLED "Diagnostic Board not installed or not detected by radio’s microcontroller.

Closing the Diagnostic Channel

The diagnostic channel between the HHT and the transceiver is automatically closed when aHHT is disconnected to the transceiver. However, if an older HHT or transceiver is beingused, it must be closed before returning the transceiver to service. To manually close thediagnostic channel when using older HHTs or transceivers, type in CLOS + ENTER . Themessage "DIAGNOSTICS IS CLOSED" will be displayed, indicating a closed condition. At thispoint it will be noticed that either the running cursor or the stationary solid flashing cursorreturns, and that all further keystrokes will be ignored by the HHT, another indication that thediagnostics channel is closed.

ZCTRL

U+

–

K*

F/

AF1

V,

Q#

)

G(

BF2

SHIFTESC

W=

R7

M4

H1

CF3

BKSP

X0

S8

N5

I2

DF4

SPACE

Y

T9

O6

3

EF5

ENTER

J

L

P

Figure 3-2. Hand-Held Terminal Keypad

NOTEThe Diagnostics Channel automatically closes after 15 minutesof no keyboard activity. If this happens, simply re-open thechannel to resume transceiver testing.

PROGRAMMING EXAMPLES

Refer to Figure 3-2 or an actual HHT for the following discussion. The following is anexample of reprograming the MDS 4310 Transceiver in the field, using the HHT. The currentparameters of operation are:

• Transmit frequency = 428.0125 MHz• Receive frequency = 438.0125 MHz


• Time-Out Timer length = 30 sec• Soft Carrier Dekey = 0 ms• Squelch Tail Eliminator = On

The transceiver is to be programmed to operate in a system requiring the followingparameters:

• Transmit frequency = 428.8375 MHz• Receive frequency = 438.8375 MHz• Time-Out Timer length = 94 sec• Soft Carrier Dekey = 4 ms• Squelch Tail Eliminator = off• Loopback Code = 1234

The list of steps and commands below will program the MDS 4310 with the required values.

1. Connect the HHT to the transceiver as previously outlined, and open the diagnosticschannel if necessary.

2. Verify the current frequencies by typing FRQ + ENTER . Display will read:

TX FRQ = 428.01250

RX FRQ = 438.01250

3. Program the new transmit frequency by typing PTX + SPACE + SHIFT +428.83750 + SHIFT + ENTER . Be sure to include the decimal point and all trailing zeros.

The display will read TX FRQ PRGMD TO 428.83750 MHZ if the information was enteredcorrectly and accepted by the microcontroller.

4. Program the new receive frequency by typing PRX + SPACE + SHIFT

438.83750 + SHIFT + ENTER , again taking care to enter in all characters.

If the information was entered properly, and accepted by the microcontroller, thedisplay will read RX FRQ PRGMD TO 438.83750 MHZ.

5. Program the time-out timer length by entering PTOT + SPACE + SHIFT

+ 94 + SHIFT + ENTER . The display will read TIME-OUT TIMER SET TO 094 SECS.

6. Program the soft carrier time by entering PSCD + SPACE + SHIFT + 4

+ SHIFT + ENTER . Display will read SOFT CARR. DEKEY SET TO 004 MS.

7. Disable the STE by typing DSTE + ENTER . The display will read SQUELCH TAIL

ELIMINATOR OFF.

8. The information entered in can now be reviewed by using the FRQ, TOT, SCD and STE

commands to review each setting.

9. Enter the loopback code by typing PLBC + SPACE + SHIFT + 1234 + SHIFT

+ ENTER . The display will change and read LOOPBACK CODE = 1234 .

10. Close the diagnostics channel by typing CLOS + ENTER before unplugging the HHT.

This completes the programming sequence.


PROGRAMMING OWNER’S INFORMATION

The information accessible by the OWM and OWN commands can be programmed by the userto allow information unique to the radio transceiver or its location to be stored in theEEPROM. Normally, this field is left blank on units as shipped from MDS.

To program these fields, proceed according to the following directions:

1. Open the diagnostics channel.

2. Type in POWN + SPACE , followed by the owners’ name, etc. This is limited to amaximum of 20 characters. When the desired information has been entered, press

ENTER . The display will read INFORMATION PROGRAMMED .

3. Type POWM + SPACE , followed by the desired message, not to exceed the maximumof 27 characters. When the desired information has been entered, press ENTER . Thedisplay will read INFORMATION PROGRAMMED .

4. Review the information by typing OWN or OWM to verify that the desired message hasbeen entered. If either message has an error in it, the information will have to be re-entered using the above steps.

5. Close the diagnostics channel.

PASSWORD PROTECTION

If password protection of programmed information (frequency, owner’s name and message,etc.) is used, the PASS command followed by the correct four-character password must beentered before the transceiver programming can be changed. Without the proper password,the programmed information and diagnostic data can only be reviewed, and no access to theprogramming commands is possible.

For more information on password protection, contact the MDS Systems Engineering.

DIAGNOSTIC EVALUATION

Using the diagnostic commands, a technician can read important voltages and levels with theHHT. These values are updated once every second, allowing adjustment of the levels withoutthe need for invoking the command each time a control is moved. Below is a list of thecommands, with the display to be expected after typing the command followed by an ENTER

keystroke.

SV ------------- Supply voltage supplied to transceiver.Display will read SUPPLY VOLTAGE = xx.x VOLTS .

VR ------------- Main regulator voltage.Display will read +8V = xx.x VOLTS .

RSSI ---------- Received signal strength at ANTENNA connector.Display will read RSSI = –xxx DBM .

LV ------------- PLL VCO lock voltage.Display will read LOCK VOLTAGE = xx.x VOLTS IL .

NOTEThe I L is an in-lock indicator; if the PLL isout-of-lock, the display will show OL.


With the radio’s transmitter keyed…

FPWR ---------- Forward RF power output of Transceiver.Display will read FWD POWER = xxx WATTS .

VSWR ---------- Calculated VSWR based on forward and reflected power levels.Display will read VSWR= x .x : x .

Test Modes

Using the Hand-Held Terminal, a technician can invoke several diagnostic and test modesthat are useful in evaluating the operation of both the transceiver and an internal modem. Thetest modes are invoked by typing the commands listed below followed by an ENTER

keystroke.

KEY ----- Keys the transmitter with the transmit modulation enabled.

DKEY ---- Unkeys the transmitter.

TEST_1-- Keys the transmitter and enables a constant DTMF Loopback test tone. Thistest is useful for measuring the radio’s diagnostic deviation level with acommunications monitor.

TEST_2-- Disables the DTMF Loopback test tone and unkeys the transmitter.

TEST_5-- Disables the transceiver’s VCO circuit.

TEST_6-- Enables the transceiver’s VCO circuit.

TEST_7-- Turns on the modem test tones and keys the transmitter for 12 seconds.

• With 1200 bps modem: 1200/2200 Hz tone.

• With 4800/9600 bps modem: Sine wave at 1/2 data rate (bps).

EQUIPMENT DIAGNOSTICS DEFINITIONS

Software is available for service personnel to use a MDS Master Station as a diagnostics toolfor system monitoring and maintenance. MDS 2000 Diagnostic and Control System softwareuses the master station to transmit a special message to all remote radios in a given systemasking one remote radio at a time to respond with a test signal. The test signal is analyzed bythe master station and the results are displayed on the screen of a personal computer runningthe MDS software. In order for the software to know which radios to poll for a test signal, an“Equipment List” must be created by the system operator which describes the address of theradio and its capabilities. The remote radio’s diagnostic address is referred to as its loopbackcode in MDS documentation and software. For more information, refer to the MDS 2000Diagnostics and Control System Software User’s Guide (MDS P/N 05-1919A01).

Since it is possible to have MDS 4310 radios of different capabilities installed in the samesystem it is very important to know the exact profiles of each unit. The following aredescriptions of the various diagnostic capabilities available for the MDS 4310 Transceiver.

All of the diagnostic modes listed in Table 3-1 are available from MDS 4310 transceiverswith a Remote Maintenance Module (P/N 03-1958A01) properly installed in jacks J5 and J7of the transceiver motherboard.


DIAGNOSTIC EXAMPLES

RF Power Output Check

Suppose you wish to read the transmitter output power while the HHT is connected. Thefollowing steps will accomplish this.

1. Connect the transceiver to a dummy load.

2. Type KEY + ENTER , to key the transmitter.

3. Type FPWR + ENTER , to display the forward power output level.

4. As a further performance check, the DC voltage supplied to the transmitter can beread by typing SV + ENTER .

5. Unkey the transmitter by typing DKEY + ENTER .

Received Signal Strength Indication (RSSI) Check

To invoke the RSSI function, simply type RSSI + ENTER on the HHT. The display indicatesthe signal level at the ANTENNA connector in dBm. The display is updated once every second.This check can be especially useful when aiming the antenna at the remote site for maximumsignal level. By using the RSSI command and the continuously updated display, an installercan aim the antenna in the direction of maximum field strength.

Table 3-1. Diagnostic and Control Capabilities

LEVEL MODE DESCRIPTION

Loopback 1 A radio set to Mode 1 diagnostics will respond to a poll containing a four-digitnumber string called the “Loopback Code.” When the remote radio decodesits loopback code transmitted by an MDS master station, it responds bykeying its transmitter for several seconds with a continuous modulating tone.The radio’s signal strength and deviation can then be measured by theMaster Station.

Advanced 2 With a radio set to Mode 2, critical diagnostic information available through alocal HHT or personal computer is available over the RF channel to theMaster Station. This includes: transmitter RF power output, the primarypower supply voltage, the internal +8 Vdc regulated voltage level, thesynthesizer’s lock voltage and the radio’s internal temperature. In addition,the diagnostic analysis of the remote unit’s signal, as received by the MasterStation receiver will be displayed on a personal computer connected to themaster station. These values include received signal level, carrier frequencyoffset (error) and modulation level/deviation.

RemoteMaintenance

3 This is the highest level of diagnostics and control capability available for theMDS 4310 transceiver. With Remote Maintenance enabled, all of the abovediagnostic capabilities are available and, in addition, many of the radio’sparameters can be adjusted either locally with an HHT or over the RFchannel with a personal computer running MDS 2000 Diagnostic and ControlSystem software. Since it provides the greatest level of diagnostics andcontrol, many users prefer to keep the transceiver set to Mode 3 diagnostics.


PROGRAMMING AND TEST COMMANDS

Table 3-2 contains a list of all HHT programming and diagnostics commands.

NOTESome command strings in Table 3-2 include an underscore “_”symbol to denote a SPACE key press. The underscore is a visualreminder only, and should not be entered.

Table 3-2. Programming and Test Commands—Part 1 of 3

DIAGNOSTICS CHANNELOPEN ... OPEN the Diagnostics Channel CLOS ... CLOSE the Diagnostics Channel

DISPLAY COMMANDSHARDWARE STATUS

STAT .... Display status of hardware profile

Displayed below are the functions of each display character and its meaning.

1 Keyed Status ................ U – UnkeyedK – KeyedT – Timed Out

2 Diagnostic Mode .......... S – Standard (Mode 1)A – Advanced (Mode 2)R – Remote Maint. (Mode 3)

3 Diagnostic Hardware ... A – Installed, LBC ValidB – Installed, LBC InvalidC – Uninstalled, LBC ValidD – Uninstalled, LBC Invalid

4 Diagnostic Module ....... I – InstalledU – Uninstalled5

Base/Remote .............. B – Base (High Side LO)R – Remote (Low Side LO)

6 IF/LO Arrangement ..... 0 – 45 MHz/Low

7 RSSI Cal. Status .......... Y – CalibratedN – Uncalibrated

8 RF Power Status.......... Y – CalibratedN – Uncalibrated

OWNER’S INFORMATIONOWM .... Display Owner’s Message OWN .... Display Owner’s Name

RADIO INFORMATIONHREV ... Transceiver hardware revision level

MD........ Transceiver manufacture date

MO ....... Model number of radio

SER...... Serial number of radio

SREV ... Transceiver firmware revision level

OPERATING PARAMETERSCTS...... Displays CTS delay in ms

FRQ ..... Frequencies currently set in MHz

LBC ...... Display Loopback code (4 digits)

SCD Display Soft Carrier Dekey in ms

PTT ...... Display Push-to-Talk delay in ms

STE ...... Display Squelch Tail Eliminator (STE)

Status— ON or OFF (Normally OFF if VOX function is used.)

TOT...... Display Time-out Timer length (sec)

DIAGNOSTIC INFORMATIONFPWR .. Forward RF power*

LV ........ PLL VCO lock voltage

RPWR .. Reverse RF power*

RSSI .... Received Signal Strength Indicator*

SV........ Supply voltage to radio*

TEMP... Internal temperature in degrees Celsius*

VR........ Regulator voltage output ≈8 Vdc*

VSWR.. VSWR at ANTENNA connector*

* Information is updated every second



DIAGNOSTIC AND TEST MODESTEST MODES

KEY ......... Keys the transmitter(Transmit modulation enabled)

DKEY ....... Dekeys the transmitter

TEST_1 ... Keys the transmitter and enables a constantDTMF Loopback test tone. Useful for checkingthe radio’s diagnostic deviation level

TEST_2 ... Disables DTMF Loopback test tone and unkeys the transmitter.

TEST_5 .... Disables VCO

TEST_6 .... Enables VCO

TEST_7 .... Turns on modem test tones and keys thetransmitter for 12 seconds.

• With 4800/9600 bps modem: Sinewave at1/2 data rate.

• With 1200 bps modem: 1200/2200 Hz tone.

DIAGNOSTIC MODESMODE_1 .......... Enable-Standard Diagnostics

MODE_2 .......... Enable-Advanced Diagnostics

MODE_3_xxxx . Enable Remote MaintenanceFunctions (xxxx is the data rate in bps)

NOTES– Remote Maintenance Module (03-1958A01)must be installed to invoke these functions.

4-wire radios in Mode 3 must use 1200 as themodem data rate.

DIAGNOSTIC CALIBRATION

These commands are used with calibrated test equipment attached to radio.

CPWR . Calibrate forward power to 5 Watts for diagnostics

RSSL ... Calibrate RSSI at –110 dBm

RSSH... Calibrate RSSI at –70 dBm

SET/PROGRAM COMMANDSOPERATING PARAMETERS

PASS_xxxx ...... Password Entry

PTX_xxx.xxxx... Program transmit frequency†

PRX_xxx.xxxx .. Program receive frequency†

PLBC_xxxx....... Program loopback code (0000–9999)

ESTE ................ Enable Squelch Tail Eliminator

PCTS_xxx ....... Program CTS Delay in ms; 2-255 ms, noleading zeros (1–3 digits)

PSCD_xxx ....... Program soft carrier dekey; 2–255 ms,no leading zeros (1–3 digits)

ETOT .............. Enable Time-out Timer

DTOT .............. Disable Time-out Timer

PTOT_xxx ........ Program Time-out timer (sec)(1–3 digits)

PPTT_xx .......... Program Push-to-talk delay (0-31 ms)

† A move of more than 6 MHz requires re-alignment of the transceiver’s tuned circuits. Consult factory for details.

POWER, FREQUENCY AND DEVIATION

A Remote Maintenance Module (P/N 03-1958A01) must be installed in the transceiver and the transceiver must be set toMode 3 Diagnostic for these commands to have any effect. Electronic controls (EEPOTs) for these parameters areincremented or decremented as a percentage of their maximum value—zero to 100 percent. Changes in these settingsare not permanent until the RMST command is sent.

GENERAL:RMRD .............. Read present EEPOT settingsRMIST .............. Store present EEPOT settingsRMIS ................ Reset all EEPOTs to 50% and store

settingsRMOV .............. Restore all EEPOT to the previously

stored settings to 50%.<SPACE> ........ Repeat last adjustment command

FREQUENCY:IF ...................... Increment Frequency by 1DF .................... Decrement Frequency by 1INCF_xx ........... Increment Frequency by xx valueDECF_xx .......... Decrement Frequency by xx value

PRIMARY MODULATION:ID ..................... Increment Deviation by 1DD .................... Decrement Deviation by 1INCD_xx ........... Increment Deviation by xx valueDECD_xx ......... Decrement Deviation by xx value

POWER:IP ..................... Increment Power by 1DP .................... Decrement Power by 1INCP_xx ........... Increment Power by xx valueDECP_xx ......... Decrement Power by xx value

OWNER’S INFORMATIONPOWN_xxxxx ....... Program owner’s name

(20 characters maximum)POWM_xxxxx....... Program owner’s message

(27 characters maximum)



REMINDERS• All command entries end with the ENTER key.

• Use the SHIFT key to access numbers; press again to return to characters.

• Square cursor ( ) – letter mode is selected.

• Rectangular cursor ( ) – number mode is selected.

• Use ESC/BKSP key to edit information or commands being typed in.

• An underlined blank space (xx_xx) on command list indicates a required space.

HAND-HELD TERMINAL SETUP DEFAULTS

Occasionally, users of the HHT will key in a sequence of characters that will alter the internalmicrocontroller operating defaults and cause it to no longer be able to exchange data with theradio. The following is a set of instructions for reinitializing the HHT for use with MDS radioproducts.

Restoring the HHT Operation Defaults

1. Plug the HHT into the radio and apply power to the radio. A small rectangular cursorwill appear on the display.

2. Put the HHT into the Setup Mode by pressing the following keys in sequence: SHIFT

+ CTRL + SPACE . The HHT responds with a screen display similar to that shown inFigure 3-3.

AF1

BF2

1

CF3

2

DF4

3

EF5

Figure 3-3. HHT Initialization Display

Reviewing and Changing Defaults

1. The first of 15 menu items will be displayed. See Table 3-3. All of the items can bereviewed by pressing the “NEXT” function controlled by the E key. The menuparameter setting can be changed by pressing the “ROLL” function controlled bythe A key.

2. Set up the HHT as listed in Table 3-3.

3. To “EXIT” the setup mode, press C for “EXIT”, or it will automatically be closedafter the final item on the setup menu has been reviewed and the “ROLL” function isselected.


Table 3-3. Hand-Held Terminal Operating Defaults

PARAMETER SETTING

Re-init HT NO

Baud Rate 1200

Comm bits 8,1, n

Parity Error OFF

Key Repeat OFF

Echo OFF

Shift Keys YES

Ctl Chars PROCS

Scroll on 33rd

Cursor ON

CRLF for CR ON

Self Test SLOW

Key Beep ON

Screen size 32

Menu Mode LONG

HAND-HELD TERMINAL WIRING

The HHT is a very reliable unit, but the 6-conductor coiled cord or its RJ-11-6 modularconnectors can be damaged by over-stretching or being dropped. The coiled cord is wired asa straight pin-for-pin assembly and the parts required to construct a replacement cable can beobtained from many electronics supply companies. Although similar in appearance, the cableset is not the same as an RJ-11-4 (4-conductor) telephone coiled cord.

Adapter Plug Wiring

Figure 3-4 shows the internal wiring of the DB-25 interface adapter plug that is used toconnect the HHT to the transceiver.

DB-25RJ-11-6

19

5

N/C

3

2

7

23

1

2

3

4

5

6

Figure 3-4. DB-25 Interface Adapter Wiring

HHT ALTERNATIVES

As an alternative to using the HHT, a PC running terminal software (such as PCPLUS™,PROCOMM™, etc.) can be used to program the transceiver. Also, any ASCII terminal


supporting a standard RS-232 interface can be used. The software commands for PC orASCII terminal control are identical to those listed for the HHT. (See Table 3-2.)

The communications settings for a PC or ASCII terminal must be as follows:

• Bit rate = 1200 bps.• Number of data bits = 8, 1 stop bit• No parity• Full duplex mode• Caps Lock enabled

Cable Wiring for a PC or ASCII Terminal

CAUTIONWhen connecting a PC or ASCII terminal to the MDS 4310Transceiver, use only the required pins specified below. Donot use a straight DB-25 to DB-25 cable wired pin for pin.The use of improper cables may cause equipment damage.

The cable connecting the PC or terminal to the transceiver must connect the TXD, RXD,DSR and signal ground pins (DB-25 INTERFACE connector pins 2, 3, 6 and 7) as shown inFigures 3-5 and 3-6. Pin 23 can be be connected to ground to automatically open thediagnostic channel. If the PC or terminal is to be used for purposes other than diagnosticsor programming, do not connect Pin 23.

NOTEA transceiver equipped with an internal modem can transmitwhen connected to a PC, because of activation of RTS. Ensurethat the ANTENNA connector has a 50 ohm termination on itbefore proceeding.

COMPUTER DB-9 RADIO DB-25

3

2

7

8

5

1

TXD

RXD

RTS

CTS

GND*

DCD

TXD

RXD

GND*

DSR

FEMALE MAL* Signal Ground

2

3

7

6

23OPEN

Figure 3-5. DB-9 to DB-25 Interface Cable Wiring

COMPUTER DB-25 RADIO DB-25

2

3

4

5

7

8

TXD

RXD

RTS

CTS

GND*

DCD

TXD

RXD

GND*

DSR

FEMALE MALE* Signal Ground

2

3

7

6

23OPEN

Figure 3-6. DB-25 to DB-25 Interface Cable Wiring


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MDS 05-2415A01, Rev. A 4-1

CHAPTER 4FIELD TESTS AND ADJUSTMENTS

DANGERThe MDS 4310-HL data transceiver is approved for use inClass I, Groups ABCD, Division 2, Hazardous Locations.The installer of these transceivers MUST be familiar withhazardous location installation guidelines before any instal-lation or maintenance is begun. Do not begin installation ofor make external connections to this device unless the areais known to be non-hazardous.


GENERAL

This chapter describes field tests and adjustments that can be used to diagnose suspected prob-lems or evaluate the transceiver after an assembly has been replaced. These tests are notnormally required for new installations (with the exception of checking the supply volt-age to the radio and testing antenna system performance). Unless otherwise noted, theprocedures given here apply equally to the MDS 4310 transceiver and the MDS 4350/4355packaged models. For additional set-up information on the MDS 4350 and MDS 4355, referto Appendices F and G respectively.

NOTEAll units are tuned at the factory for optimum performance. Donot re-tune any unit without first checking the performance asit is. Retuning may not be necessary.

TEST EQUIPMENT REQUIRED

Directional RF Wattmeter—It must be equipped with a plug-in element rated for 10 wattsand 1,000 MHz. A popular directional wattmeter suitable for this service is the BirdModel 43 Thruline™ wattmeter with the Bird 10D element.

Service Monitor— This is an instrument that performs the combined functions of RFand audio signal generator, frequency meter/counter, modulation analyzer and RFwatt–meter. Monitors are typically equipped with an input attenuator/dummy loadthat allows the full output of the transmitter to be safely coupled directly to theinstrument. If this last feature is not provided, you will need a separate attenua-tor/dummy load. Suitable service monitors are manufactured by the IFR Division ofRegency, Inc., Marconi Instruments Ltd., and Hewlett Packard. It is also possible touse separate test equipment in place of a service monitor, but this may be impracticalfor field work.


4-2 FIELD TESTS & ADJUSTMENTS MDS 05-2415A01, Rev. A

TEST EQUIPMENT REQUIRED Continued

Frequency measuring equipment usually requires a “warm-up” period to achievemaximum accuracy; a warm-up period of 30 minutes is not uncommon. Please readthe unit’s instruction manual before proceeding with frequency measurements.

NOTEFCC regulations require a frequency accuracy of .00015% (1.5ppm). MDS transceivers meet this requirement by usingtemperature compensated crystal oscillators. A frequency counterused to set the transceiver on-frequency must have an accuracythat is five to ten times better than what it is reading, which is anaccuracy of .00003% to .000015% (0.3 to 0.15 ppm).

If a frequency counter with a frequency accuracy of better than 0.3ppm is not available, do not make any adjustments to thetransceiver frequencies.

DC Voltmeter—A digital voltmeter such as a Fluke 75 is suitable.

Oscilloscope—If the service monitor does not contain a low frequency oscilloscope, thena basic one is required. The oscilloscope should have a frequency response of 100kHz or higher, AC/DC coupling and have a horizontal sweep resolution of 2 ms perdivision.

MDS Hand-Held Terminal (HHT) —Kit P/N 02-1501A01. The HHT is mostconvenient way to set the operating parameters controlled by the transceiver’s micro-controller, and to use the built-in test and diagnostic features of the radio.

NOTETo perform the tests in this chapter, operators must be familiarwith connecting the HHT, opening and closing the DiagnosticsChannel and issuing the required commands. Chapter 3—Programming and Diagnostics contains complete instructionsfor using the HHT.

If desired, a personal computer running a standard terminal emulation program suchas PCPLUS™ or PROCOMM™ can be substituted for the HHT. In this case, theprogram should be set to 1200 bps, eight data bits, no parity, and one stop bit. Thekeyboard must be set with the caps lock key pressed; the radio responds only tocommands and numbers entered in uppercase characters. The commands for a PC areidentical to those used with the HHT. (See Chapter 3—Programming andDiagnostics, for more information.)

Room Thermometer—This thermometer should be accurate to 1°C. It is used tocalibrate the temperature sensor on the Remote Maintenance Module.

Power Supply—The output needs to provide 12–14 Vdc at 3 amperes or more.

Small, flat-bladed adjustment tool—It is used to adjust potentiometers on thetransceiver. It should be made of plastic or metal.

Data Terminal Emulator—This device is required for radios with a built-in modeminstalled. It is used to key the transceiver and simulate incoming data on the DB-25INTERFACE connector. A simple terminal emulator can be wired for this purpose as

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-3

shown in Figure 4-1. The transceiver’s INTERFACE connector must be configured forRS-232 operation for proper operation of the emulator. (See “Special Instructionsfor Radios Configured as TTL” below if your radio has been configured for TTL.)

NOTEAs an alternative to a Data Terminal Emulator, a “breakoutbox” or jumpers can be attached to the transceiver’s INTERFACEconnector and configured with the proper connections asshown in Figure 4-1.

Special Instructions for Radios Configured as TTL

In most cases, a data terminal emulator can be plugged directly into theradio’s INTERFACE connector and used immediately. However, in somecases, the INTERFACE connector may have been previously configuredfor TTL operation (as opposed to the more common RS-232 format) usingthe radio’s J11 jumper field.

If you are unsure of which configuration you have, look at J11 on thetransceiver’s motherboard. In an RS-232 radio, all pins on J11 will beempty (open), with the possible exception of a jumper on Pins 13 and 14(LEDs enabled). By contrast, a TTL radio will have jumpers installed on allpins of J11, with the possible exception of Pins 13 and 14.

If your radio is configured for TTL, an optional TTL to RS-232 adapter plugis available from MDS (P/N 03-2223A01) to allow connection of the DataTerminal Emulator, an HHT or other RS-232 equipment. This unit plugsbetween the transceiver’s INTERFACE connector and the externalequipment, making the transceiver appear as an RS-232 device. Contactthe factory for ordering information.

If the TTL to RS-232 adapter plug is not available, it is also possible totemporarily reconfigure the INTERFACE connector for RS-232 operationby removing the jumpers on J11. (See Table 2-4 for proper jumperplacement.) When testing is complete, J11 can be restored to its TTLconfiguration.

CONSTRUCTING A DATA TERMINAL EMULATOR

Introduction

The right side of Figure 4-1 shows the proper wiring for a simple data terminal emulator.There are two ways to construct the Data Terminal Emulator; both techniques are electricallyidentical and use common parts available from most electronic parts supply stores. Thedifference is in the packaging of the two units.

Emulator Design #1

Method 1 requires two small toggle switches (SW1 & SW2), and a DB-25 male connectorwith a cover that is large enough to mount the toggle switches inside it. (See the top part ofFigure 4-2.)

Emulator Design #2

Method 2 requires two toggle switches (SW1 & SW2), a DB-25 male connector, a shortlength of three-conductor cable, and a small enclosure. (See the lower part of Figure 4-2.)


SW1

SW2

TERMINALEMULATOR

RADIOTRANSCEIVER

RTS

DSR

TXD

+5 VDC

1 K

Male DB-25Connector

Pin 6

Pin 2

Pin 4

SPACE MARK

STANDBYXMTR KEYED

TransceiverInterface

Connector

Figure 4-1. Remote Data Terminal Emulator WiringSW1 and SW2 mounted inside a small enclosure

SW1(RTS)

SW2(TXD)

SMALL ENCLOSURE(Plastic or Metal)

TOGGLE SWITCHES(SPST)

3 CONDUCTOR CABLE

DB-25 MALECONNECTOR

METHOD TWO

SW2(TXD) SW1

(RTS)

METHOD ONESMALL TOGGLE

SWITCHES (SPST)

Figure 4-2. Construction Options for Building a Data Terminal Emulator


Switch Functions

Listed below are the functions of the two toggle switches referred to in Figure 4-1. Thesefunctions are called for in many of the test procedures which follow.

• Closing SW1 keys the transmitter by setting the RTS line high.

• SW1 must be closed in order for SW2 to emulate transmit data (TXD). Transmit datais emulated as follows:

Closing SW2 emulates a “Space” condition.Opening SW2 emulates a “Mark” condition.

REMOTE MAINTENANCE CONSIDERATIONS

General

If your radio is equipped with a Remote Maintenance Module (P/N 05-1958A01 installed inJacks J5/J7), some of the tests and alignments which follow must be done using softwarecommands from the Hand-Held Terminal (HHT) and not with the on-board adjustments.

The HHT icon shown below indicates that the paragraph to its immediate right describes anaction to be taken on transceivers equipped with Remote Maintenance.

The description given below is an example only, and is one of many descriptions of this typein this manual. HHT programming and control commands are shown in uppercase BOLDTYPE. Table 3-2 contains a complete list of HHT programming and control commands.

RM

Use the SER command to read the serial number assigned to the transceiver.

NOTETo perform the tests in this chapter, operators must be familiarwith connecting the HHT, opening and closing the DiagnosticsChannel and issuing the required commands. Chapter 3—Programming and Diagnostics contains complete instructionsfor using the HHT.

Presettings

The Remote Maintenance Module has three electronic potentiometers (EEPOTs) that areelectrically in parallel with the frequency, deviation and RF power potentiometers on thetransceiver motherboard. Before any alignment of the transceiver is started, the EEPOTsmust be preset to their initial settings (50%) using the RMIS command from the HHT. Thethree potentiometers on the transceiver motherboard must then be preset to the positionslisted in Table 4-1.

After the potentiometers on the motherboard are preset, you should adjust the transmitter’soutput power (using the HHT) according to the instructions given in Test Procedure ➊. Youshould then proceed with the required test procedures listed in Table 4-2.

NOTEThe settings of the EEPOTs can be checked at any time byentering the RMRD command on the HHT keypad. The HHTdisplays the settings of all three EEPOTs on one screen.


Table 4-1. Main Circuit Board Potentiometer Settings for Remote Maintenance

DESIGNATOR FUNCTION POSITION

R69 TX Power Output Maximum CW

R168 TX Deviation Maximum CW

R69 and R168 are multiturn controls that should be advanced at least 10 turns, or until afaintly audible clicking sound is heard from the potentiometer. This sound indicates the endof the control’s range.

After these potentiometers are preset to the positions listed in Table 4-1, the technicianshould adjust the transmitter’s output power (using the HHT) according to the instructionsgiven in the BASIC TRANSCEIVER TESTS section. (Page 4-7.)

Then, the technician should proceed with the required alignment procedures in the ordergiven below. A separate section is provided for each modem configuration installed in thetransceiver—no modem, 1200 bps, 4800 bps, and 9600 bps. These sections cover transceiveradjustments for Transmit Frequency, Squelch, Deviation, and Receive Audio Output.

NOTETo store Remote Maintenance adjustments, you musttype RMST. If the settings are not stored, the radio willrevert to the previous settings when the power isremoved from the transceiver.

INTRODUCTION TO FIELD TESTS & ADJUSTMENTS (See Figure 4-9)

The following test procedures in this chapter are arranged according to the hardwareconfiguration of the MDS 4310 transceiver. The primary difference between units is thepresence of a modem—no modem, 1200 bps modem, 4800 bps modem, or 9600 bps modem.There is also a “Basic Tests” section that applies to all radio configurations, and a separatesection for adjustment and checkout of the Remote Maintenance Module (if one is installed).

Refer to Table 4-2 to locate the required tests and proceed directly to those sections thatapply to your radio. All of these procedures assume the radio is powered up and connected toa dummy load or antenna as required.

Table 4-2. Test Procedure Reference Chart

For alignment instructions relating to... Procedure

Basic Transceiver Checks—Applies to all radio configurations ➊

Radios with no internal modem installed ➋

Radios with a 1200 baud modem installed ➌

Radios with a 4800 baud modem installed ➍

Radios with a 9600 baud modem installed ➎

Remote Maintenance Module (with or without a modem installed) ➏


NOTEThe transmitter will be turned off by the time-out timer if thetransmit period exceeds the programmed time out value. Tocontinue testing, simply unkey and key the transmitter to resetthe timer. The factory default value for the time-out timer is180 seconds.If desired, the time-out timer may be disabled during thesetests, by sending the DTOT command from the HHT keypad. Besure to restore the timer to its original setting when testing iscomplete.

NOTEThe Diagnostics Channel (the link between the HHT and theradio) “times out” after 15 minutes of no HHT keypad activity.If this happens, you will need to re-open the DiagnosticsChannel to resume transceiver testing.

TEST PROCEDURE ➊:BASIC TRANSCEIVER CHECKS —Applicable to all hardware configurations

Introduction

This section describes basic checks that apply to all common configurations of the MDS4310 transceiver. The checks covered are:

• Power supply• Transmitter power output• Antenna VSWR

These checks should be made before starting any detailed troubleshooting or alignment of thetransceiver. See Figure 4-9 for the locations of adjustable controls on the transceivermotherboard.

Power Supply Check

1. Connect the power supply to the transceiver.

2. Remove the transceiver’s cover by loosening the four captive screws along theperimeter of the case.

3. Measure the power supply voltage at the transceiver power connector.

RM

With Remote Maintenance installed, the supply voltage can be checked byentering the SV command on the Hand-Held Terminal.

If necessary, adjust the power supply voltage to 13.8 Vdc. If the voltage is notadjustable, make sure the nominal value is between 12 and 15 volts.

4. Momentarily key the transmitter by the KEY and DEKEY commands.

5. The voltage should drop no more than 0.4 Vdc while the transceiver is keyed.


Transmitter Power Output Check

1. Connect a directional wattmeter between the transceiver and the antenna feedline.

2. Connect the HHT to the transceiver and open the Diagnostics Channel.

3. Key the transmitter by entering KEY. This command keys the transmitter until theDKEY command is entered (or until the time-out period has been reached).

4. Check the output power of the transceiver. If necessary, adjust it for the desiredlevel, or a maximum of 5 watts, using R69 on the transceiver motherboard. Do notexceed 5 watts.

RM

If Remote Maintenance is installed, set R69 fully clockwise and use theIP / DP / INCP / DECP commands to adjust the output power. The IP / DPcommands increment/decrement the power in single steps while the INCP /DECP commands make larger jumps by adding a space and a number to thecommand. (Example: INCP_20 + ENTER to increase the power by 20 stepsout of 100). When finished, type RMST to store the setting.

CAUTIONIn systems operating with battery power, make sure that thebattery is fully charged before attempting to set thetransceiver output power. If the power is set for 5 watts withreduced battery voltage, the transceiver will put out morepower when the battery becomes fully charged, which maycause a violation of FCC rules and drain the battery morequickly than expected.

Antenna VSWR Check

1. Connect a directional wattmeter between the transceiver and the antenna feedline.

2. Key the transmitter by entering KEY. This command keys the transmitter until theDKEY command is entered (or until the time-out period has been reached).

3. With the transmitter keyed, set the directional wattmeter to measure the power in thereverse direction, to measure the reflected power from the antenna. This should readless than 0.5 watt. If the reading is higher, problems with the antenna or feedline areindicated. Check all connections and ensure that the cable connectors are installedproperly. Make sure the antenna is not damaged, and is the correct model for thisfrequency band.

CAUTIONDo not put the radio into service until reflected power prob-lems are corrected, as they can degrade system performanceand shorten equipment life.


If an in-line wattmeter is not available, the HHT can be used to obtain a roughindication of the reflected power from the antenna system. Use FPWR to measureforward power, and RPWR to measure the reflected power. The calculated VSWR canbe read using the VSWR command.

NOTEThe built-in power output and VSWR metering functions areprovided for the convenience of service personnel for makingquick checks of the radio’s performance. They are notsubstitutes for calibrated test equipment.

4. Dekey the transmitter and remove the directional wattmeter from the antenna circuit.

VCO Lock Voltage Adjustment

In order for the radio to switch quickly between transmit and receive, the VCO rangecapacitor is adjusted so that the lock voltage does not change between transmit andreceive modes. This adjustment requires monitoring the lock voltage with a DC voltmeteron the transceiver motherboard or on the HHT using the LV command if the RemoteMaintenance Module is installed.

1. Place voltmeter at test point shown in Figure 4-3 or use the HHT to measure theVCO lock voltage. The voltage should be between 2 and 7 Vdc.

2. Key the radio with the KEY command.

3. Monitor the voltage. The nominal voltage is not important, it should not vary morethan one tenth of a volt between transmit and receive modes.

4. If the voltage difference is greater than one tenth of a volt, adjust the VCO RANGEcapacitor C247, on the transceiver PC board until the lock voltage is the same (± 0.1Vdc) in the transmit and receive mode. C247 is available through the shield of theVCO sub-assembly.

VCO LOOP VOLTAGE TEST POINT

VCO ASSEMBLY

SHIELD

C247VCO RANGE

(THRU SIDE OF SHIELD)

Figure 4-3. VCO Lock Voltage Test Point

This completes the basic tests of the MDS 4310 Transceiver.


TEST PROCEDURE ➋:TRANSMIT FREQUENCY, SQUELCH, DEVIATION,AND RECEIVE AUDIO OUTPUT—For Radios with No Internal Modem

Remove the cover from the transceiver by loosening the four captive cover screws and liftingit straight up. See Figure 4-9 for the locations of adjustable controls.

Transmit Frequency

1. Connect the transceiver’s ANTENNA connector to the input of the service monitorusing a short length of RG-8/U or RG-214 coaxial cable.

2. Key the transmitter by entering KEY on the HHT or use the Transmit Test Switch.The KEY command keys the transmitter until the DKEY command is entered or untilthe time-out period has passed.

3. Measure the transmitter frequency. It should be within 100 Hz of the assignedfrequency. If not, adjust the transmitter frequency on the TCXO.

RM

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commandsinstead of adjusting the Frequency Adjust on the TCXO. The IF / DFcommands increment/decrement the frequency in single steps while theINCF / DECF commands make larger jumps by adding a space and a numberto the command. (For example: INCF_8 to increase the frequency by eightsteps out of 100.) When finished, type RMST to store the setting.

4. Unkey the transmitter and reconnect the interface cable to the external modem orRTU.

Receive Audio Output Level

The receive audio output level of the transceiver is factory-set for 0.7 Vp-p (–10 dBm) at600 Ω, at rated system deviation. If a third party modem is used with the MDS 4310, consultits instruction manual to determine what audio input level the modem needs. Should adifferent level be required, adjust the Receive Audio Output Level, R292, on the transceiverboard as follows:

1. Generate an on-channel signal modulated with a 1 kHz tone, at the proper deviationlevel (commonly 2.5 kHz), to provide an audio signal for adjustment purposes.Monitor the level at the input to the modem (or at Pin 11 of the INTERFACEconnector) using the oscilloscope in the service monitor. Adjust R25 on the maintransceiver board for the desired level.An alternate method is to adjust R25 when data signals from the master station arepresent and audio tones can be seen on the scope.

2. Reconnect the feedline directly to the ANTENNA connector of the transceiver. Placethe unit in normal operation with the associated master station.

Squelch Adjustment

1. Consult the RTU instruction manual to determine if squelch action in the radio isrequired for normal operation. If squelch action is not required, set SquelchThreshold, R41, fully counterclockwise (open squelch) and skip the remaining stepsof this procedure. If you are unsure on this point, assume that squelch action isrequired and perform the following procedures.

2. Remove the feedline from the ANTENNA connector.


3. Using an oscilloscope set for DC coupling at 2 V or 5 V per division, observe theReceiver Unsquelched (RUS) signal at Pin 10 of the INTERFACE connector.

4. Insert an on-channel signal at –120 dBm (.225 µV), with a 1 kHz tone and 2.5 kHzdeviation. Adjust R41 fully counterclockwise while observing the oscilloscopedisplay.

5. Set the squelch to be fully closed at this signal level by advancing R41 until theoscilloscope pattern changes from about 8 V to 0 V. Watch for noise on the scopedisplay, and advance R41 slightly farther, if necessary, until the signal level remainsat about 0 V.

Transmitter Deviation

1. Inject a test tone equivalent to the RTU audio output level (typically 1200 or2200 Hz) into the radio at Pin 9 of the INTERFACE connector.

2. Key the transmitter by entering KEY on the HHT, or by grounding the radio’s “not”PTT line (Pin 16).

3. Observe the deviation on the service monitor, and adjust it to 2.5 kHz using R168,TX DEV.

RM

If Remote Maintenance is installed, set R168 fully clockwise and use theID / DD / INCD / DECD commands to adjust the deviation. The ID / DD com-mands increment/decrement the deviation in single steps while the INCD /DECD commands make larger jumps by adding a space and a number to thecommand. (Example: INCD_4 to increase the deviation by four steps out of100.) When finished, type RMST to store the setting.

4. Unkey the transmitter using the DKEY command.

5. Close the Diagnostics Channel and disconnect the HHT from the transceiver.

Putting Things Back Together

1. Reconnect feedline and interface cables to transceiver, and reinstall the cover.

2. Confirm that the unit operates properly with the associated RTU. (Typically, thetransceiver should be transmitting intermittently in response to polling signals fromthe master station.

3. Secure all cables, providing strain relief if necessary, and check connectors fortightness.

This completes the set-up of the MDS 4310 transceiver without a modem installed.

TEST PROCEDURE ➌:TRANSMIT FREQUENCY, SQUELCH, DEVIATION,AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 1200 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the DataTerminal Emulator (Figures 4-1). See Figure 4-2 for an assembly drawing of the 1200 baudmodem. See Figure 4-9 for the locations of adjustable controls on the transceiver mother–board.



TEST PROCEDURE ➌: (Continued)TRANSMIT FREQUENCY, SQUELCH, DEVIATION,AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 1200 BPS Modem

Set-up

1. Remove the cover from the transceiver by loosening the four captive cover screwsand lifting it straight up.

2. Connect the HHT and open the Diagnostics Channel.


4. Close the Diagnostics Channel and disconnect the HHT.

5. Connect the Data Terminal Emulator to the INTERFACE connector.

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed/SW2 Open). This generates acontinuous Mark tone.

2. Measure the transmit carrier frequency; it should be within 100 Hz of the assignedfrequency. If not, adjust the transmitter frequency using the Frequency Adjustmenton the TCXO.

RM

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commandsinstead of adjusting the TX Frequency Adjustment control on the TCXO.The IF / DF commands increment/decrement the frequency in single stepswhile the INCF / DECF commands make larger jumps by adding a space and anumber to the command. (For example: INCF_8 to increase the frequency byeight steps out of 100.) When finished, type RMST to store the setting.

Data Deviation

1. Adjust the service monitor to read modulation deviation. With the transmitter stillkeyed (SW1 Closed), the deviation should be 2.5 kHz ±100 Hz. If not, adjust R168,TX DEV. for the proper deviation.

RM

If Remote Maintenance is installed, set R168 fully clockwise and use theID / DD / INCD / DECD commands to adjust for 2.5 kHz deviation. TheID / DD commands increment/decrement the deviation in single steps whilethe INCD / DECD commands make larger jumps by adding a space and anumber to the command. (Example: INCD_4 to increase the deviation by foursteps out of 100.) When finished, type RMST to store the setting.

2. Measure the Mark tone frequency. It should be 1200 Hz ± 10 Hz. If not, adjust R2 onthe modem board.

3. Close SW1 and SW2 to generate a Space tone.

4. Check the transmitter’s deviation. It normally falls within 0.5 kHz of the Mark tone’sdeviation.

5. Measure the Space tone’s frequency. It should be 2200 Hz ± 10 Hz. If not, adjust R3,Space, on the modem board.

6. Unkey the transmitter by removing the Data Terminal Emulator.

7. Turn off S1-3 on the modem PC board.


8. Generate an on-channel signal at –60 dBm (225 µV), with 1 kHz modulation at2.5 kHz deviation.

9. Adjust the transceiver’s R25 for 1.2 Vp-p ± 0.05 V at U3 pin 8 (on the maintransceiver PC board) as read on the oscilloscope.

10. Set the service monitor modulation frequency to 1700 Hz.

11. Touch the oscilloscope probe tip to the top of chip resistor R33 on the modem board.

12. Adjust R25 (on the modem) for a square wave on the scope. Remove the probe.

13. Turn off the service monitor and disconnect the coax from the transceiver’s ANTENNAconnector.

14. Adjust the squelch by observing the receiver audio output signal at Pin 11 of theINTERFACE connector using an oscilloscope.

15. Adjust R41 on the transceiver’s motherboard fully counterclockwise, and observe thenoise voltage on the oscilloscope. Now slowly rotate R41 clockwise to a point justbeyond that where the noise disappears. Watch the scope for a few seconds and, ifnecessary, continue to advance R41 until the receiver remains fully squelched (thenoise no longer appears intermittently).

R3SPACE TONE

(2200 HZ)FREQUENCY

R2MARK TONE

(1200 HZ)FREQUENCY

R25RECEIVE DATA

DETECTORTHRESHOLD

ADJUST

J6 J8

R33

R33RX TEST POINT

Figure 4-4. 1200 bps AFSK Modem; MDS P/N 03-1815AXXSee Table A-1 in Appendix A for details on switch settings.

Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe theReceiver Unsquelched (RUS) signal at Pin 10 of the INTERFACE connector.

2. Insert an on-channel signal at –120 dBm, with a 1 kHz tone and 2.5 kHz deviation.Adjust R41, Squelch Threshold, fully counterclockwise while observing theoscilloscope display.

3. Set the squelch to be fully closed at this signal level by advancing R41, SquelchThreshold, until the oscilloscope pattern changes from about 8 V to 0 V. Watch fornoise on the scope display, and advance R41 slightly farther, if necessary, until thesignal level remains at about 0 V.



1. Restore the transceiver’s time-out timer to the original value (if changed) using thePTOT_XXX command on the HHT. The factory default setting is 180 seconds.

2. Reinstall the cover. Reconnect the antenna feedline and reconnect the RTU’sinterface cables to the transceiver.

3. Confirm that the unit operates normally with the associated RTU.

4. Secure all cables, providing strain relief if necessary, and check connectors fortightness.

This completes the set-up of the transceiver with a 1200 baud modem installed. Foradditional information on the 1200 baud modem refer to Appendix A.

TEST PROCEDURE ➍:TRANSMIT FREQUENCY, SQUELCH, DEVIATION,AND RECEIVE AUDIO OUTPUT—For Radios with MDS’s Internal 4800 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the DataTerminal Emulator (Figure 4-2). See Figure 4-5 for an assembly drawing of the 4800 baudModem. See Figure 4-9 for the locations of adjustable controls on the transceivermotherboard.

Set-up

1. Remove the cover from the transceiver by loosening the four captive cover screwsand lifting it straight up. Make a list of the settings of configuration switch S1 on themodem—they will be changed temporarily during the alignment procedure.



4. Connect the transceiver’s ANTENNA connector to the input of the service monitorusing a short length of RG-8/U or RG-214 coaxial cable. Set up the service monitorto monitor the transmitter’s center (channel) frequency.

5. Set the transmitter deviation to minimum by rotating R168, Deviation, fully counterclockwise.

6. On the modem, set S1 to positions 2 and 4 ON (Closed), all others OFF (Open).

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed). The TXD line should be at logiclow (LED annunciator TD [TXD] off).

2. Check for correct transmit center frequency. With TXD low (SW2 Open) thetransmitted frequency should be within 100 Hz of the assigned center frequency. Ifnecessary, adjust the TX Frequency Adjustment control on the TCXO.

RM

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commandsinstead of the adjustment on the TCXO. The IF / DF commandsincrement/decrement the frequency in single steps while the INCF / DECFcommands make larger jumps by adding a space and a number to thecommand. (For example: INCF_8 to increase the frequency by eight steps outof 100.) When finished, type RMST to store the setting.


Data Deviation

1. With the transmitter still keyed (SW1 Closed), increase the deviation by rotatingR168 clockwise to cause the frequency to shift down from the assigned centerfrequency by 1.6 kHz ± 75 Hz.

RM

If Remote Maintenance is installed, set R168 to its full-clockwise positionand use the ID / DD / INCD / DECD commands to set the downward frequencyshift to 1.6 kHz. The ID / DD commands increment/decrement the deviationin single steps while the INCD / DECD commands make larger jumps byadding a space and a number to the command. (Example: INCD_4 to increasethe deviation by four steps out of 100.) When finished, type RMST to storethe setting.

2. Set the TXD line high (SW2 Closed). Observe the carrier frequency shifting up 1.6kHz ± 75 Hz from the assigned center frequency. If it does not, alternately adjust theTX Frequency adjustment on the TCXO and R168, checking both high and lowfrequencies for equal 1.6 kHz shifts.

Note—There is some interaction between R168 and the TX Frequency adjustment onthe TCXO. If the shift is equal in both directions, but exceeds 1.6 kHz, it may benecessary to turn the deviation down slightly and repeat this step. Continue toalternately adjust R168 and the TX Frequency adjustment on the TCXO until equal1.6 kHz shifts are obtained.

3. Set RTS and TXD low (SW1 and SW2 Open).

4. Set S1-3 on the modem to ON. This generates a data test pattern of 101010.

5. Set RTS high (SW1 Closed).

P8 P6

S1CONFIGURATION

U6

U5

8 1 OFF (OPEN)

(CLOSED)

U3

Pin 3ON

Figure 4-5. 4800 BPS FSK Modem; MDS P/N 03-1831A01See Table B-1 in Appendix B for details on switch settings.

6. Adjust the HF Audio Compensation control, R179, if necessary, to produce 2.7 kHz±75 Hz deviation as measured on the service monitor.

7. Set RTS low (SW1 Open) and turn OFF S1-3 on the modem.

8. Set the service monitor to generate a –60 dBm (225 µV) on-channel signal with a1 kHz tone at 2.5 kHz deviation.

9. Connect an oscilloscope set to a 5 ms timebase to U3 Pin 3 on the modem. AdjustR25 (Receive Audio Level) on the transceiver’s motherboard for a waveformshowing a 0.7 to 0.75 Vp-p sinewave riding on 2.5 Vdc.


Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe theReceiver Unsquelched (RUS) signal at Pin 10 of the radio’s INTERFACE connector.

2. Insert an on-channel signal at –120 dBm (.225µV), with a 1 kHz tone and 2.5 kHzdeviation. Adjust R41, Squelch Threshold, fully counterclockwise while observingthe oscilloscope display.



1. Restore the transceiver’s time-out timer duration to the original value (if changed)using the PTOT_XXX command on the HHT.

2. Restore the modem’s Configuration Switch, S1, to its original settings or asrecommended in Table B-1 of Appendix B of this manual.

3. Reconnect the RTU’s interface cables to the transceiver and reinstall the cover.Reconnect the antenna feedline.

4. Confirm that the unit operates normally with the associated RTU. Secure all cables,providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the transceiver with a 4800 baud modem installed. Foradditional information on the 4800 baud modem refer to Appendix B.

TEST PROCEDURE ➎:TRANSMIT FREQUENCY, SQUELCH, DEVIATION,AND RECEIVE AUDIO OUTPUT—For Units with MDS’s Internal 9600 BPS Modem

In the following procedures, references to SW1 & SW2 relate to the switches of the DataTerminal Emulator (Figure 4-2). See Figure 4-6 for an assembly drawing of the 9600 baudModem. See Figure 4-9 for the locations of adjustable controls on the transceivermotherboard.

Set-up

1. Remove the cover from the transceiver by loosening the four captive cover screwsand lifting it straight up. Make a list of the settings of configuration switch S1 on themodem—they will be changed temporarily during the alignment procedure.



4. Connect the transceiver’s ANTENNA connector to the input of the service monitorusing a short length of RG-8/U or RG-214 coaxial cable. Set up the service monitorto monitor the transmitter’s center (channel) frequency.

5. Set the transmitter deviation to minimum by rotating R168, Deviation, fully counterclockwise.

6. On the modem, set S1 to 6 & 7 ON (Closed), all others OFF (Open).


P8 P6

S1CONFIGURATION

U6

U5

8 1 OFF (OPEN)

(CLOSED)

U3

Pin 7 ON

Figure 4-6. 9600 BPS FSK Modem; MDS P/N 03-1833A01See Table C-1 in Appendix C for details on switch settings.

Transmit Frequency

1. Key the transmitter by raising RTS (SW1 Closed). The TXD line should be at logiclow (LED annunciator TD [TXD] off).

2. Check for correct transmit center frequency. With TXD low (SW2 Open) thetransmitted frequency should be within 100 Hz of the assigned center frequency. Ifnecessary, adjust the TCXO frequency adjustment (on the transceiver’smotherboard), to place it on frequency.

RM

If Remote Maintenance is installed, use the IF / DF / INCF / DECF commandsinstead of adjusting the TX Frequency adjustment on the TCXO. The IF / DFcommands increment/decrement the frequency in single steps while theINCF / DECF commands make larger jumps by adding a space and a numberto the command. (For example: INCF_8 to increase the frequency by eightsteps out of 100.) When finished, type RMST to store the setting.

Data Deviation

1. With the radio still keyed (SW1 Closed), raise TXD (SW2 Closed). This shouldcause the transmitted frequency to shift by 1.6 kHz ±75 Hz either up or down.

It does not matter if the frequency shifts up or down; the way it shifts depends onlyupon the phase of the modem’s internal 9600 Hz clock at the instant the TXD linechanged. If the TXD line is toggled, the transmit frequency should change betweenthe assigned center frequency when TXD is low and 1.6 kHz on either side of centerwhen TXD is high. If necessary, adjust R168 on the transceiver motherboard toobtain a 1.6 kHz ±75 Hz shift.

RM

If Remote Maintenance is installed, set R168 to its full-clockwise positionand use the ID / DD / INCD / DECD commands to set the frequency shift to1.6 kHz. The ID / DD commands increment/decrement the deviation in singlesteps while the INCD / DECD commands make larger jumps by adding a spaceand a number to the command. (Example: INCD_4 to increase the deviationby four steps out of 100.) When finished, type RMST to store the setting.

2. Toggle TXD high (SW2 Closed) until the frequency shifts opposite from above. Thefrequency should shift 1.6 kHz ±75 Hz. If not, alternately adjust the TX Frequencyadjustment on the TCXO and R168 on the transceiver’s motherboard, toggling TXD,checking both the high and low frequencies for equal 1.6 kHz shifts.



Data Deviation (Continued)

Note—There is some interaction between R168 and the TX Frequency adjustment onthe TCXO. If the shift is equal in both directions, but exceeds 1.6 kHz, it may benecessary to turn the deviation down slightly and repeat this step. Continue toalternately adjust R168 and the TX Frequency adjustment on the TCXO until equal1.6 kHz shifts are obtained.

3. With the high and low shifts equal, set TXD low (SW2 Open). The transmitfrequency should be within ± 200 Hz of the assigned (channel) frequency. If not,adjust the TX Frequency adjustment on the TCXO as described in the TransmitFrequency procedure above.

4. Set RTS high (SW1 Closed) and turn ON S1-3 on the modem.

5. Adjust the Transmitter HF Audio Compensation control, R179, if necessary, toproduce 2.7 kHz ± 75 Hz deviation as measured on the service monitor.

6. Unkey the radio by setting RTS low (SW1 OPEN).

7. Turn OFF S1-3 on the modem.

Receive Audio Output Adjustment

1. Generate a –60 dBm (225 µV) signal on the receive frequency with 1 kHzmodulation at 2.5 kHz deviation.

2. Using an oscilloscope set to a 5 ms timebase, observe the waveform at U3 Pin 7 onthe modem board; it should be a 0.7 to 0.75 Vp-p sinewave riding on 2.5 Vdc. If not,adjust the Receive Audio Level control, R25 (on the transceiver’s motherboard), toproduce 0.7 to 0.75 Vp-p at TP1.

Squelch Adjustment

1. Using an oscilloscope set for DC coupling and 2 V or 5 V per division, observe theReceiver Unsquelched (RUS) signal at Pin 10 of the INTERFACE connector.

2. Insert an on-channel signal at –120 dBm (.225 µV), with a 1 kHz tone and 2.5 kHzdeviation. Adjust R41, Squelch Threshold, fully counterclockwise while observingthe oscilloscope display.



1. Restore the transceiver’s time-out timer duration to the original value (if changed)using the PTOT_XXX command on the HHT.

2. Restore the modem’s Configuration Switch, S1, to its original settings or asrecommended in Table C-1 of Appendix C.

3. Reconnect the RTU’s interface cables to the transceiver and reinstall the cover.Reconnect the antenna feedline.

4. Confirm that the unit operates normally with the associated RTU. Secure all cables,providing strain relief if necessary, and check connectors for tightness.

This completes the set-up of the transceiver with a 9600 baud modem installed. Foradditional information on the 9600 baud modem refer to Appendix C in this manual.


TEST PROCEDURE ➏:REMOTE MAINTENANCE MODULE—Loopback Code Programming, Mode Selection, Calibration & Testing

Introduction

The Remote Maintenance Module (Figure 4-7) is a small PC board assembly that mountsvertically into Jacks J5 and J7 of the transceiver PC board. The module contains twoadjustable controls—Loopback TX Audio Level (R6), and Temperature Setting (R33).Normally, R6 needs adjustment only when the module is first installed in the radio. R33 isadjusted at the factory.

The following procedures are not required for units shipped from the factory with RemoteMaintenance installed. Perform these procedures only if the Remote Maintenance Module isbeing newly installed, is known to be out of adjustment, or if the Remote MaintenanceModule is being replaced.

NOTEIf you are unsure whether a Remote Maintenance Module isinstalled in the transceiver, open the Diagnostics Channel withthe Hand-Held Terminal and enter the STAT command. Thedisplay responds with the type of diagnostics that are installedin the transceiver. The forth character will show an I if themodule is installed, or a U if it is not installed. (See Table 3-2 tointerpret the full response.)

R6LOOPBACK TX AUDIO LEVEL

J7 J5

R33TEMP. SET

Figure 4-7. Remote Maintenance Module (P/N 03-1958A01)

NOTEIn a properly aligned system, Remote Maintenance providesvaluable information to service personnel, however, it is not asubstitute for calibrated test equipment.

Loopback Code Identification

A loopback code is used to identify the radio during diagnostics operations. Each radio in thesystem must have a unique four digit numerical loopback code for Remote Maintenancediagnostics to work properly. The code should be one that is not being used elsewhere in thesystem in which the radio will be installed; duplicate codes can cause failure in or incorrectdata from radios having the same loopback codes.

To determine the current loopback code, connect the HHT to the radio and open theDiagnostics Channel. Next, type LBC. The radio responds by displaying the code on the HHT


display. (Units shipped from the factory are pre-programmed with a default loopback codeconsisting of the last four digits of the radio’s serial number.)

The displayed loopback code is followed by the characters UI (uninstalled) or I (installed) atthe end of the second line in the display to indicate the presence of a Remote MaintenanceModule. If no loopback code has been entered, the indication will be UI for uninstalled, evenif the module is present, since a valid loopback code has not been entered. When theloopback code is entered, and the radio is shut down and re-powered up, the indicator will beI for installed.

Programming a New Loopback Code

If you wish to program a new loopback code, type PLBC_XXXX , where the underline character,“_”, is a space and “XXXX” is a four digit address code. This code identifies the unit duringdiagnostic polling by the master station. Note—the code must contain four digits and noletters. After the new loopback code has been entered, the radio responds by displaying thecode on the HHT display.

Diagnostics Mode Selection

The Remote Maintenance Module can be set for one of three levels (modes) of diagnosticsand control. The MODE command is used to set the diagnostics and control mode. ReviewTable 3-1—Diagnostics and Control Capabilities for detailed descriptions of the threeoperating modes. MODE_3xxxx is used to invoke Remote Maintenance, the highest level ofdiagnostics. Since it provides the highest level of diagnostics and control, many users preferto keep the radio set up for Remote Maintenance.

Diagnostics Deviation Adjustment

1. Loosen the four cover screws and remove the top cover from the transceiver bylifting straight up.


3. Set the service monitor to receive at the transceiver’s transmit frequency.

4. Connect the transceiver’s power cord and apply power.

5. With the Hand-Held Terminal (HHT) connected to the INTERFACE connector, openthe Diagnostics Channel using the OPEN command.

6. If Remote Maintenance is not already enabled, type MODE 3 xxxx , where xxxx is thespeed in bits per second (i.e., 1200, 4800 or 9600 bps) of the internal data modemplugged into Jacks J6 and J8. If the radio is not equipped with an internal MDSmodem, use MODE 3 1200.

7. Type TEST_1 to activate a DTMF test tone and key the transmitter.

8. Measure the transmitter deviation on the service monitor. If the deviation is not2.5 kHz, adjust it to 2.5 kHz using R6, TX Audio, on the Remote MaintenanceModule. (See Figure 4-6.)

9. Type TEST_2 to disable the test tone and unkey the transmitter.

Temperature Calibration

The Remote Maintenance Module has a built-in temperature sensor used to measure the ra-dio’s internal temperature during operation. The temperature sensor has been calibrated at the


factory and the need for field adjustment of this parameter is rare. Nevertheless, instructionsare given below. If the temperature calibration is misadjusted, its value in remote (over-the-air) and local diagnostics will be compromised.

1. Measure the temperature at or near the transceiver chassis using a thermometer thatis accurate to 1°C. The transceiver must be at room temperature.

2. Use the TEMP command to obtain the temperature reading for the radio. The readingis in degrees Celsius.

3. If there is a difference between the thermometer reading and the TEMP indication,adjust potentiometer R33, TEMP SET, on the Remote Maintenance Board to obtain amatch between the measurements taken on the HHT and those taken with thethermometer. (See Figure 4-7.) The measurement given by the HHT is updated onceper second. That is, the TEMP command does not have to be invoked after eachadjustment of R33.

4. Close the Diagnostics Channel to the transceiver. and disconnect the HHT.

5. Reinstall the cover on the transceiver.

Forward Power & RSSI Calibration

If a Remote Maintenance Module is added to a transceiver as a field upgrade, or a module istransferred from one radio to another, two diagnostic measurements need calibration formaximum accuracy. These are the forward power (FPWR) and received signal strength (RSSI)functions.

Procedure

1. Connect a 50 Ω dummy load through a directional wattmeter to the ANTENNAconnector of the transceiver.

2. Connect the HHT to the INTERFACE connector of the transceiver.

3. Key the transmitter with the KEY command from the HHT. Type KEY + ENTER .

4. Set the transmit power output to 5 watts using the TX Power Output level control,R69, on the transceiver motherboard as indicated on the in-line directionalwattmeter.

5. Enter the calibrate power command, CPWR, from the HHT. Type CPWR + ENTER . Theforward and reflected power detectors will be automatically calibrated.

6. Dekey the transmitter with the DKEY command from the HHT. Type DKEY + ENTER .

7. Disconnect the directional wattmeter and dummy load from the ANTENNA connector.

8. Connect a communications service monitor to the ANTENNA connector.

9. Inject an on-channel unmodulated –110 dBm (.710 µV) signal.

10. Enter the calibrate received signal strength low level command, RSSL, from the HHT.Type RSSL + ENTER . The low level RSSI calibration point is automaticallycalibrated.

11. Increase the signal level to –60 dBm (225 µV) signal.

12. Enter the calibrate received signal strength high level command, RSSH, from theHHT. Type RSSH + ENTER . The high level RSSI calibration point will beautomatically calibrated.


13. Enter the received signal strength command, RSSI, from the HHT. Type RSSI +ENTER . The display shows the current received signal level in dBm. Check the

calibration with the communications service monitor set between –60 dBm (225 µV)and –120 dBm (.225 µV).

14. This completes the calibration procedure. Disconnect the HHT and communicationsservice monitor.

Testing The Remote Transceiver With The Master Station—Optional Checkout

This section provides abbreviated instructions for testing Remote Maintenance with aproperly equipped Master station on a service bench. This test simulates over-the-air RemoteMaintenance using a PC and MDS 2000 Diagnostics and Control System software. Completeinstructions for using the software are contained in the MDS 2000 Diagnostics and ControlSystem software User’s Guide (P/N 05-1919A01).

1. Connect the transceiver to the Master Station using coaxial cable through at least100 dB of attenuation. The attenuators at each end of the connection should be ratedto continuously withstand at least 5 watts of RF power.

2. Attach the PC through one of its serial ports to the DIAGNOSTIC connector on the rearof the MDS 2100 Master Station.

3. Set the Master Station’s rear-panel DTE/DCE switch to DCE if you’re using astraight-through serial cable, or DTE if you’re using a null-modem cable.

4. Load the MDS 2000 Diagnostics and Control System software on the PC and openthe Diagnostics Channel to the Master Station.

5. Using the software’s Equipment List Editor, select the Remote transceiver to betested and set the radio’s diagnostic level to Remote Maintenance.

6. Return to the polling screen and verify that you can perform a diagnostic poll on theremote radio.

7. Press F4 to invoke Remote Maintenance. The Remote Maintenance screen for thattransceiver appears. (See Figure 4-8.)

8. The software displays the Remote radio’s transmit frequency error compared to themaster station’s receive frequency. The offset (or difference) should be within 0.3kHz; If not, adjust the MDS 4310 transmit frequency as described in the FieldAlignment instructions in this chapter.

9. Verify that the DTMF deviation display indicates approximately 2.5 kHz. If nomodem is installed in the transceiver, skip ahead to Step 11. Otherwise, proceed withStep 10.

10. Press F3 to toggle the deviation display from DTMF to DATA. If the data deviationis 2.7 kHz ±0.2 kHz, proceed to the next step. If not, adjust the MDS 4310 deviationas described in the Field Alignment instructions in this chapter.

11. If the power output is not set to the desired output level (usually 5 watts), use the← → arrow keys to select the POWER bar and the ↑ ↓ arrow keys to increase ordecrease the output level as desired. The POWER bar also shows the reflected powerlevel and includes a VSWR summary—OK, CHECK SYS, or BAD.

12. Press F4 to store the changes within the Remote Maintenance Module.

13. Press Esc to close Remote Maintenance of that Remote unit and return to theprevious screen.


14. This completes the Remote Maintenance checkout procedure. For additionalinformation on the Remote Maintenance Module refer to Appendix D.

MICROWAVE DATA SYSTEMS -- REMOTE MAINTENANCE ADJUSTMENT

--- REMOTE UNIT (8802) ---

16

15

14

13

12

11

10

9.0

7.5

6.0

4.5

3.0

1.5

0

SUPPLYVOLTAGE

13.9V

POWER (W)REF / FWD / VSWR0.3 / 4.8 / OK

--- MASTER MONITORING OF ---

+6.0

+4.0

+2.0

0

–2.0

–4.0

–6.0

–50

–60

–70

–80

–90

–100

–110

6.0

5.0

4.0

3.0

2.0

1.0

0

SIGNALSTRENGTH

–59dBm

FREQOFFSET0.3KHz

DATADEVIATION

2.6KHz

STATUS

REMOTE UNITTEMPERATURE

+25.0°C

POWER[ 56 ]

FREQ40

DATA DEV.65

--- REMOTE CONTROL SETTINGS ---

AFC is currently set to (OFF)[F6] AFC Off [F7] Rx AFC [F8] Tx/Rx AFC[F3] Toggle DTMF/DATA Deviation Display[F2] Update Screen [F4] Store ChangesPress (Esc) to Exit or Use (Arrow) keys to select and change a Control Setting

Figure 4-8. Remote Maintenance Screen

MDS 05-2415A01, Rev. A FIELD TESTS & ADJUSTMENTS 4-25/26

J6

R25RECEIVE

AUDIO LEVEL

J14RX AUDIO

NORMAL/INVERTOPTION BOARD 2J5 & J7

J1EXTERNALINTERFACE

LEDINDICATORS

J2DC POWER

INPUT

F14A FUSE

R41SQUELCH

THRESHOLD

R69TX POWER

OUTPUT

TX FREQ.

C247VCO RANGE(THRU SIDE OF SHIELD)

J4ANTENNA

OPTION BOARD 1J6 & J8

J8

J7 J5

R179HF AUDIO

COMP.

INV.

Z1 Z2

R168TX DEV.

J11SHUNT ASREQUIRED

RS-232DISABLE

LEDENABLE

J16FULL DUPLEXINTERFACE

3

4

1

2

NORM

L25

L8

T1

Figure 4-9

MDS 4310 Transceiver 2314Axx PC BoardTest Points and Adjustments

Potentiometer types may differ from those shown.

MDS 05-2415A01, Rev. A 5-1

CHAPTER 5—THEORY OFOPERATION

For the following discussion, see Figure 5-1, the radio’s block diagram at the end of thischapter.

RECEIVE FRONT END

Connector J4 on the main PC board conducts the RF signal from the front panel ANTENNAconnector to the antenna switch network. In the receive mode, one port of the antenna switchconducts the receive signal to the input of helical filter Z1.

The output of Z1 is fed to RF amplifier Q1. The output of Q1 goes to helical filter Z2. Theoutput of Z2 goes to M1, a double-balanced mixer whose local oscillator injection signal isderived from the VCO output.

HIGH IF

The 45 MHz High IF signal from M1 enters the IF amplifier. The output of IF amplifierconnects to L25 as an input matching transformer. The receive signal is then passed to FL1Aand FL1B. FL1A and FL1B are components of a 4-pole crystal filter that provides some ofthe IF selectivity of the receiver. The output of FL1B is conducted to U32, which containsthe low IF amplifier and other functions.

LOW IF

U32 contains several circuit sections: mixer, oscillator, IF amplifier/limiter, quadrature detec-tor and received signal strength indication driver. The second 44.55 MHz LO for U32 isderived from the TCXO. A frequency tripling circuit multiplies the 14.85 MHz TCXO signaland triples it up to 44.55 MHz. This is consequently mixed with the 45 MHz IF to form the450 kHz IF.

The 450 kHz output of the second mixer is fed to a ceramic filter set consisting of FL2 andFL3. This filter set provides the main adjacent channel selectivity of the receiver.

The output of FL3 is fed to the limiter amplifier input pin of U32. The limiter output is fed toa quadrature detector circuit tuned by discriminator coil T1; recovered audio is passed toU3A audio buffer.

A secondary output of the IF subsystem of U32 gives a received signal strength indication(RSSI) voltage. The RSSI signal is used by the remote maintenance module and is availableat the INTERFACE connector J1-21 through a buffer and scaler, U3C.

RECEIVE AUDIO

The unfiltered recovered audio from the IF discriminator passes through amplifiers U3A,U3B and configuration jumper J14.

5-2 THEORY OF OPERATION MDS 05-2415A01, Rev. A

The output of the squelch gate goes to the modem receive audio amplifier, U5A. U5A is anamplifier with the gain set by potentiometer R25. R25 is used to adjust the receive audiolevel supplied to the modem and remote maintenance boards.

U5D and U5C are an audio lowpass filter that removes noise from the receive audio. Theoutput of this filter goes to external modems through J1.

SQUELCH

The squelch circuit consists of a high-pass filter, noise amplifier, noise rectifier and acomparator.

The high pass filter U6A removes low frequencies of the detected IF output. The output ofU6A goes to a gain stage, U6B, which amplifies the high frequency noise. The gain of U6Bis set by R41, which is the squelch threshold adjustment.

The amplified high frequency noise output from U6B goes to a full-wave rectifier, whichcompares this DC voltage with a fixed reference voltage. U6C, which rectifies the noisesignal. The output of this stage goes to a squelch comparator, U6D whose output is thereceiver unsquelch sensor (RUS) line, and is used to control squelch gate U26A in the receiveaudio path. This gate is also controlled by the RX MUTE signal from U19D.

The RUS logic signal is also fed to the modem and is used to gate the DCD output from themodem. In addition, this signal appears at J1 pin 10 through a 1 kΩ resistor.

POWER SUPPLY

The + 13 volt DC input appears when an external power source is connected to J2. From J2,the + 13V is conducted to the internal transceiver circuits through F1, a 4 ampere fuse. Thefuse protects the transceiver in the event the external, in-line fuse is either defeated orreplaced with one of a higher rating.

Z4 is a EMI power line filter. C77 is a electrolytic capacitor. These two devices help providea noise free power source for the transceiver circuits. A 17 volt zener diode across C77provides over-voltage and reverse polarity protection.

U38 provides a regulated + 8 volts for most transceiver circuits. U13 provides a regulated + 5volts, which supplies power to the microcontroller and the logic circuitry.

U45 is a low voltage protection device. It will disable the radio when the input voltagebecomes less than 10 volts. The output from U45 drives the radio disable circuit Q15 whichdisables the 8 volt and 5 volt regulators, U38 and U13.

A precision reference DC voltage of + 2.5V is supplied by U4; this is used by the FSKmodem circuitry.

The RX/TX signal from the microcontroller applies + 8 volts to the RF amplifier, high IFamplifier and tripler circuit in the receive mode, and is shut off in the transmit mode.

Q19 supplies a biasing signal to the transmitter amplifiers and antenna switch. Q19 is turnedon during transmit by the microcontroller.

The main transmit power control signal from the microcontroller, TXE2, is first conditionedby U46 whose output is sent to the power control potentiometer R69. The wiper of R69 isconnected to U44B which is a power-leveling circuit. U44B drives U44A, Q41 and Q43which form an adjustable voltage regulator. The output of this regulator feeds the powercontrol pin on U33

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-3

The transmitter can be turned off, independent of microcontroller control, by the synthesizerout-of-lock signal. An out-of-lock condition at the synthesizer will bring the O/L line high,overriding the power control signal TXE2.

TRANSMIT POWER AMPLIFIER

The power amplifier chain of the transmitter section consists of U40 and U33. U40 is adriving amplifier for U33. The output of U40 is fed to hybrid power module U33. The powercontrol of U33 is controlled by the power control regulator Q3 and U44A.

The RF output of U33 is fed through a directional coupler to the antenna switching network.

ANTENNA SWITCH

The antenna switch consists of PIN diodes and a filter network. In the receive mode, PINdiodes are unbiased and effectively disconnected from the circuit. Under this circumstance,the received signal is free to pass to the input of helical resonator Z1 through a low passfilter.

During the transmit mode, the PIN diodes are biased ON by the Q19. When the diodes areconducting, one diode provides a low impedance path for the transmit signal to the ANTENNAconnector and the other diode shorts out the capacitor in the switching circuit. With thecapacitor shorted, the filter network is equivalent to a quarter wave transmission line with noRF current flowing through the inductor.

DIRECTIONAL COUPLER

The directional coupler is used during diagnostic measurements of forward and reflectedpower at the ANTENNA connector. The directional coupler consists of an in-line transmissionline section that conducts RF energy from power amplifier U33 to the antenna switch.Coupled line sections located immediately adjacent to, and either side of the transmissionline, receive a sample of the RF energy passing through the coupler. Rectifiers mounted oneach end of coupled line sections produce DC voltages. These DC voltages are proportionalto the power levels appearing on the coupled lines.

The directional coupler provides a forward power measurement that can be displayed throughlocal diagnostics when the radio has the Remote Maintenance Module installed.

KEYLINE AND CONTROL CIRCUITS

There are three push-to-talk (PTT) inputs to the keyline control circuit. Three negative inputsand one positive going input. The negative going inputs come from J1-16, the modem, andthe audio processing board. These are inverted and added to the positive going input comingfrom J1 pin 14. This signal drives the keyline inverter U19A.

RADIO DISABLE

J1-Pin 12, is the input to the radio disable circuit. The radio disable circuit minimizes powerconsumption by shutting off all of the transceiver circuits except for Q15 and CR32B. Thisallows the user to inhibit transceiver functions with an open-collector interface circuit.

J1-Pin 12 should be left open to permit the transceiver to function normally.


If J1-Pin 12 is grounded U13 and U38 are disabled. Since U38 supplies current to nearly allof the transceiver circuits, current consumption in the transceiver is reduced essentially tozero. This eliminates the need to externally switch the +13 volts applied to the transceiver.

AUDIO/DATA MODULATION INPUT SWITCHING

One section of U15, switch U15X, controls data appearing at the RXD terminal, Pin 3 of J1,switching between modem data and microcontroller data from U16. Another section, U15Z,switches the transmit audio path between the modem transmit audio output and the externaltransmit audio input to the transceiver from J1.

U15Z is controlled by means of a modem enable line which is tied to +10 volts when themodem option is installed.

Without the modem installed, the normal state of U15Z is such that transmit audio from J1Pin 9 modulates the transmitter. With the modem installed, the external transmit audio fromJ1 is cut off, and modem transmit audio is selected.

Should the positive-going push-to-talk (PTT) input on J1-14 be driven high (to key thetransmitter—such as when the external order wire option is used), U19B pulls the control linefor U15Z low. This allows external transmit audio in from J1 to modulate the transmitter, andcuts off any audio coming from the modem.

MICROCONTROLLER/EEPROM

The microcontroller, U16, controls many of the on-board functions of the transceiver. Someof the control functions are:

• Frequency Programming and Control of the Synthesizer

• Modem RTS/CTS Delay

• Transmitter Time-out Timer

• Transmit Soft Carrier Dekey Delay

• Transmit Squelch Tail Eliminator Delay

• Loopback/Diagnostic Functions

U16 runs a predetermined routine that controls its functions; this routine is permanentlyprogrammed within the IC and cannot be altered. All programmable functions and values arestored by the microcontroller in an electrically erasable, programmable, read-only memory(EEPROM) IC, U18. These include operating parameters such as frequency, time-out timerlimits, soft carrier dekey times, and CTS delay time, as well as model and factory serialnumbers. U16 and U18 share a common clock and exchange data through data lines.

The microcontroller can be reset by several different means. An error output from U13 drivesthe reset line low causing the microcontroller to reset or the internal modem can drive thereset line from J8. The error signal from U13 resets U16 allowing a stable initialization when13 Vdc is first applied to the transceiver.

The inhibit line on U13 is controlled indirectly by the radio enable line available at J1-12.The inhibit line on U13 will force a microcontroller reset through the error output line.

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-5

DIAGNOSTICS DATA CONTROL

Communications between the microcontroller U16 and an external terminal, PC or the HHTis accomplished by means of the TXD (J1–Pin 2) and RXD (J1–Pin 3).

U16 constantly monitors transmit data input on J1–Pin 2, and ignores all data unless theOPEN command from the external programmer is detected or a ground is detected on J1–Pin23. The receive data output on J1–Pin 3 is normally connected to the output of the modemdemodulator when a modem is used. When the OPEN command is detected, U16 switchesthe receive data path from the modem to its own data output port in order to allow it tocommunicate directly with the terminal.

The receive data control pin of U16 controls the normally high base of Q8. When thediagnostic channel is opened, Q8 is turned off, thus switching the state of gate U15X. Thisallows data from the microcontroller to appear at the RXD output (J1-Pin 3).

TRANSMIT AUDIO

The transmit audio circuit consists of a variable gain amplifier, active low-pass filter, and asumming amplifier. The variable gain amplifier U28C gain is set by R168. The transmitaudio then passes through a low pass filter consisting of U28B and associated components.The output of U28B, and transmit audio from the remote maintenance board, are summedtogether in amplifier U28D.

Transmit audio is also fed to the VCO input by means of a R179, which is the high frequency(HF) compensation control. This control provides a balanced transmit audio frequencyresponse.

PLL/SYNTHESIZER

The temperature compensated 14.85 MHz crystal oscillator (TCXO) generates the referencefrequency for the phase-lock loop (PLL) circuit.

U36 is a CMOS PLL synthesizer consisting of a phase detector, a programmable referencedivider, a programmable feedback divider, and prescaler. Data input is serially loaded fromU16; this data consists of binary coded numbers representing the reference and feedback(VCO RF sample) divider ratios required to produce the final transmit frequency. Thereference divider is programmed only on power-up, with a power reset or with a PLLout-of-lock condition. The feedback divider value changes according to the transmit/receivefrequencies entered by the PTX and PRX commands, and is reloaded from the EEPROM everytime a transmit-to-receive or receive-to-transmit transition occurs.

The phase detector output of U36 is fed to the VCO tuning input through an R-C loop filter.A sample of transmit audio modulation of the VCO is fed to the loop filter from the wiper ofR179.

The lock detector output of U36 is applied to U28A. When the PLL is in lock, U36 shuts offU28A and keeps the O/L line low. An out-of-lock condition causes U28 to drive the O/L linehigh. The O/L line inhibits the transmit regulator, as previously described in the POWERSUPPLY section; also, it is conducted to J1-Pin 25, through a 1 kΩ resistor.

RS-232 DATA INTERFACE

U31 is an RS-232 line driver/receiver integrated circuit with an input/output disable function.It has an internal +5 volts to ±10 volt converter that allows it to provide an RS-232


compatible output. Transient protection for the five RS-232 I/O lines from J1 isaccomplished by means of zener protection diodes. Static discharge or over-voltage conditionappearing on J1 will be shunted to ground with these devices before reaching U31.

In the data signal interface between the plug-in modem assembly and the main transceiverboard (i.e., the plug in modem option), the signals are inverted from standard RS-232 signalpolarity. The inverted signals, namely RXD(L), TXD(L), DCD(L), RTS(L), and CTS(L), arefed directly to U31.

Header J11 allows the TTL option to be selected. When the pins 1 and 2 of J11 are connectedtogether, U31 is disabled. This effectively removes U31 from the circuit.

LED INDICATORS

U29 and U5 drive the LEDs. U29 is a non-inverting buffer. A jumper across J11, pins 3 and 4is required to enable the LEDs.

PWR

This LED, CR31B, is illuminated if more than 10 volts is applied to the radio. It flashes ifthe VCO is Out-of-Lock. U5B is a flasher circuit.

RTS

This LED, CR31A, is illuminated if any of the Push-To-Talk lines is active.

TX

This LED, CR32B, is illuminated if the transmitter power control is active.

TXD

This LED, CR32A, is illuminated if the RS-232 transmit data line is low.

CD

This LED, CR33B, is illuminated if the receiver detects a carrier strong enough to breaksquelch.

RXD

This LED, CR33A, is illuminated if the RS-232 receive data line is low.

MDS 05-2415A01, Rev. A THEORY OF OPERATION 5-7/8

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L3 2L3 3

XM

I T

U2 9

O/L

(J1-

25)

U5 B

LED

FLA

SH

ER

U31

+5V

CR

31 BC

R33 A

CR

32 BC

R33 B

CR

32 AC

R31 ADC

PO

WE

R

R D T D C D TX

RS

(R

TS

)

E N

J11

LED

SE

NA

BLE

RT

S(J6-

12)

CT

S(J6-

6) TD

X(J1-

2) RX

D (J1-

3) RT

S(J1-

4) CT

S(J1-

5) DC

D (J1-

8) TX

C

LK(J

1-15

)

RX

C

LK(J

1-17

)E

XT

. C

LK(J

1-24

)

(J6-

23)

(J6-

21)

(J6-

20)

E NJ1

1(O

UT

)R

S-2

32E

NA

BLE

(IN

) T

LLE

NA

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L2 5

L 8

Z 5

C24

2

LIN

ED

RIV

ER

RE

CE

IVE

R

Figure 5-1.MDS 4310 Transceiver Block Diagram

MDS 05-2415A01, Rev. A 6-1

CHAPTER 6—TROUBLESHOOTING

If difficulties are experienced with the radio system, the steps outlined below can help isolatethe faulty component. For specific instructions on performing the tests or adjustments rec-ommended in this chapter, refer to Chapter 4—Field Tests and Adjustments. For instructionson using the Hand-Held Terminal (HHT), refer to Chapter 3—Programming andDiagnostics.

Troubleshooting assistance is also available from Microwave Data Systems in Rochester, NY(Telephone No. (716) 242-9600). Please have the complete model number and serial numberof the transceiver ready when calling for assistance. Refer to the inside back cover of thismanual for more information on obtaining factory assistance.

UNIT DOES NOT TRANSMIT OR RECEIVE

1. Power Supply Evaluation

a. Check for + 13.8 Vdc at transceiver’s primary power connector.

b. Check the in-line fuse in the power cable assembly; if defective, replace withtype 3AG, 3 A fuse.

c. Check for continuity of plug-in fuse F1 (4A/Fast Blo) on the transceivermotherboard. If it is blown, check for reverse polarity or excessive voltage onprimary power leads. When the problem has been corrected, replace the fuse.

2. Antenna System Evaluation

a. Check antenna feedline and connections. VSWR should be no higher than 1.5:1.Higher VSWR values usually will not prevent the radio from functioning, butmay degrade system performance.

3. Operating Frequencies Review

a. Check the transmit/receive frequencies and other radio operating parametersusing HHT or PC terminal.

UNIT RECEIVES, BUT DOES NOT TRANSMIT

1. PTT Circuit Evaluation

a. Check keying signal being supplied by RTU. Measure keyline input at DB-25INTERFACE connector; either Pin 14 or 16 of this connector should be activated.Alternate—Pin 4 of the INTERFACE connector.

b. Apply + 5 Vdc to Pin 14 (PTT), of the DB-25 INTERFACE connector, or a groundto Pin 16 PTT of the DB-25 connector. The transceiver should key.

c. On modem-equipped radios, check the DB-25 INTERFACE connector for properRTS (Pin 4) and CTS (Pin 5) signals.

d. Key transmitter with HHT using the KEY command.


6-2 TROUBLESHOOTING MDS 05-2415A01, Rev. A

2. Transmitter Power Measurement

a. Measure transmitter power output at the ANTENNA connector with an in-linewattmeter or a service monitor. It should not exceed 5 watts.

3. Transmit Modulation Evaluationa. Check to see that transmit audio connections are properly made.b. Check transmitter deviation and adjust, if necessary.

4. Transmit Frequency Measurementa. Check transmit carrier frequency with a service monitor or frequency counter

(± 0.000015% accuracy).

UNIT TRANSMITS, BUT DOES NOT RECEIVE

1. Receive Audio Evaluationa. Check for receive audio on Pin 11 of the DB-25 INTERFACE connector.b. Check for proper receive frequency programming using HHT or PC terminal.c. Check that RUS line (Pin 10 of DB-25) goes high with a received signal.

2. Interface Functions—With Diagnostics Board Installeda. Check power supply voltage (SV).b. Check 8 volt regulator (VR).c. Check PLL VCO lock voltage (LV).d. Check RSSI voltage (RSSI).e. Check power output (KEY & FPWR).f. Check programmed transmit and receive frequencies (FRQ).

UNIT RECEIVES AND TRANSMITS, BUT SYSTEM PERFORMANCE IS POOR

1. Transmitter Evaluationa. Check transmit carrier frequency with a service monitor or frequency counter

(± 0.000015% accuracy).b. Check transmitter modulation (≈2.5 kHz).c. Check RF output power level. It should not exceed 5 watts.

2. Receiver Evaluationa. Check receive 12 dB SINAD sensitivity at Pin 11 of DB-25 connector

(–117 dBm/0.3 µV).b. Check audio output level.c. Check squelch threshold level. Squelch should open at a level greater than

–120 dBmd. Check Master Station received signal strength using the HHT and the RSSI

command, or measure the DC voltage at Pin 21 of the INTERFACE connector.(See Figure 2-4 to interpret the DC signal level in dBm.)

MDS 05-2415A01, Rev. A TROUBLESHOOTING 6-3

3. Antenna System Evaluationa. Inspect antenna for damage; the feedline for loose, shorted or waterlogged

connections.b. Check forward and reflected power at ANTENNA connector of transceiver using

in-line wattmeter (VSWR should be less than 1.5:1).

4. Interface Functions Evaluation

a. Check for secure interface connections at the RTU and at the transceiver.

b. Check the RTS/CTS delay setting—it should be normally be set to a minimumof 10 ms.

c. Check to see if data is lost at beginning or end of transmission. If lost atbeginning, suspect problem with RTU keyline interface; if at end, squelch tail orsoft carrier dekey timing problems.

d. If soft carrier dekey is needed, check for proper programming of delay withHHT or PC terminal.

e. If noise from the squelch tail (closing) is interfering with the data flow, thenenable the Squelch Tail Eliminator function in the MDS 4310 using the ESTEcommand with the HHT. (Applies to analog systems only.)

f. Check for excessive length of the interface cable. This cable should be only aslong as necessary to reach the radio. If the length exceeds 50 feet, then anRS-232 to RS-422 Converter Assembly may be required. (MDS P/N 01-2358A01.)

6-4 TROUBLESHOOTING MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A A-1

APPENDIX A—1200 BPS BELL 202TCOMPATIBLE MODEM

Optional System Equipment

Assembly P/N: 03-1815A01

INTRODUCTION

The 03-1815A01 modulator/demodulator (modem) was designed specifically for use with theMDS 4300 Series Transceivers, allowing it to be mounted within the transceiver housing intoOption 1 jacks—J6 and J8. Figure A-1 shows an assembly drawing of the 1200 bps modem.

This modem is compatible with the Bell 202T standard and is normally used for a 1200 bit-per-second (bps) data rate. It will track input data rates as low 50 bps. With this optionmounted within the transceiver enclosure, the MDS 4310 Transceiver can still be pro-grammed through the RS-232 connector, without the need to remove the housing cover.

J8J6

Figure A-1. 1200 bps Modem PC Board

SPECIFICATIONS

Current Drain: 20 mA from the primary power source

Tone Frequencies: Mark: 1200 Hz, adjustableSpace: 2200 Hz, adjustable

Data Rates: 50–1200 bps Asynchronous

ALIGNMENT

Chapter 4—Field Tests and Adjustments contains alignment procedures for radios equippedwith 1200 bps modems. The modem alignment consists of setting the Mark tone frequency(R2), Space tone frequency (R3), and the Receive Data Threshold (R25).

A-2 APPENDIX A MDS 05-2415A01, Rev. A

THEORY OF OPERATION (Refer to Figure A-1 and Figure A-2)

Modulator

The modulator consists of a monolithic function generator integrated circuit, U2, whichgenerates an audio tone whose frequency depends on the state of Pin 9, the data input. Avoltage-controlled oscillator is included in the IC, the frequency of which is determined byeither R2 or R3. When Pin 9 is high, R2 and C3 determine the frequency of oscillation. WhenPin 9 is pulled low, R3 and C3 control the frequency of the oscillator, whose output appearsat Pin 2 of U2.

Normally, for operation in the Bell 202 format, R2 is adjusted to produce a 1200 Hz “mark”tone and R3 is set for a 2200 Hz “space” tone. Transmit data is supplied to Pin 9 of U2.

Demodulator

U5 is a phase-locked loop (PLL) FSK demodulator. Frequency-shifted audio from the radioreceiver is applied at Pin 2, which is one input of a phase detector. The other input to thephase detector is the internal voltage-controlled oscillator (VCO), the frequency of which isdetermined by C29 and R25. An error voltage is developed by the phase detector when theincoming audio signal frequency differs from the VCO frequency. This error voltage isapplied to a comparator, whose output is the recovered data information.

A lock detect signal is also derived from the PLL circuit, and this is used to provide a datacarrier detect (DCD) logic signal to the RTU.

Keyline (PTT) Dropout Delay

In order to prevent possible data errors from a noise burst at the termination of the transmitmodulation tone, U3 provides a supervisory control of the data modulator, U2. U3 makessure the Data Modulator is turned off at the end of a data transmission only when themodulating signal has reached the zero or cross-over point.

MDS 05-2415A01, Rev. A APPENDIX A A-3

PTTDELAY

DATA MODULATOR

LOW PASSFILTER

TX AUDIO OUTU4A

U2C3

MODEM RUS

R2MARK

ADJ.

R3SPACEADJ.

RX AUDIO INU4B

LOW PASSFILTER DATA

DEMODULATOR

U6

DCDGATE

R25THRESHOLDADJ.

C29

U6B

TXD

RXD

DCD

MODEM PTT

RTS

5 VREGULATOR

+ 10V10 V

REGULATOR

+ 13V IN

RE

U7 U8 + 5V

U5

U3

On-Board Voltage Regulator & Power Control

Figure A-2. Bell 202T Compatible Modem Block Diagram

A-4 APPENDIX A MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A B-1

APPENDIX B4800 BPS FSK MODEM



INTRODUCTION

The 03-1831A01 modulator/demodulator (modem) was designed specifically for use with theMDS 4300 Series Transceivers, allowing it to be mounted within the transceiver housing.

This modem is capable of synchronous or asynchronous operation. With this option mountedwithin the transceiver enclosure, the MDS 4310 Transceiver can still be programmed via theRS-232 connector, without the need to remove the housing cover.

SPECIFICATIONS


Data Rates: 50 to 4800 bps—Asynchronous,w/internal direct FSK interface

4800 bps—Async/Synchronous,w/internal direct FSK interface

INSTALLATION

The 03-1831A01 modem installs within the transceiver housing on the transceiver mainboard at J6 & J8. The modem contains an eight section set-up and test switch, S1, which isused to configure the modem for operation in a number of installation arrangements. TableB-1 describes the function and recommended setting of each of these eight switch sections.

ALIGNMENT

There is no “alignment” of the MDS 4800 bps modem required. However, should the modembe added to a radio that previously did not have a modem, or a defective modem is replacedwith a new one, it is advisable to check the radio’s deviation and frequency setting beforereturning the radio to service. Details on setting the deviation and frequency are covered inChapter 4—Field Tests & Adjustments.

THEORY OF OPERATION

Transmit Data

CTS is factory set to go high 10 ms after transmit data is received from the external systemvia Pin 2 on the INTERFACE connector. The time period is controlled by the micro-controller,U16, on the transceiver board, but the period is user programmable (2 to 255 ms). This datagoes through U31 on the transceiver main board for the RS-232 configuration or through

B-2 APPENDIX B MDS 05-2415A01, Rev. A

bypass jumpers in place of U31 in the TTL configuration. The transmit data is fed into thedata processor U6.

Level shifting and wave shaping operations cause the data to resemble a smooth audio wave-form. This waveform feeds into the modulation input of the transmitter. Deviation and centerfrequency are controlled by the transmitter.

Unlike radios with analog modems installed, the transmitter does not transmit a constantcarrier at center frequency when RTS is raised and no data is being sent. It can transmit asignal above or below the center frequency, depending upon whether the data is a mark or aspace.

With an RS-232 interface, a “Mark” (the normal resting state when no data is being sent),causes the transmitted frequency to be 1.6 kHz below the nominal center. If the TXD line istied high (continuous Space), the frequency will be 1.6 kHz above the nominal center. Whilecontinuous data is being sent, the frequency measures approximately the nominal channelfrequency as the carrier toggles back and forth about the center frequency.

For a TTL interface configuration, a “Mark” is a digital “high” or binary “1” and the “Space”is a digital “low” or a binary “0”.

TCRCETC

U7

RS-232INTERFACE

TX

AUDIO OUT

RXD

TXD

PTT

TAE

DCD

5 VREGULATOR

+ 10V10 VREGULATOR

+ 13V IN

RE

U7 U8 + 5V

U3D

U3C U3B

SYNC-ASYNCCONVERTOR

PROM

U5 U4

MODEMRX AUDIO

S1OPTION SELECT

SWITCHES

RUS

LOW PASS FILTER

U8

DATA SLICER

DATA PROCESSOR

U6

POWER REGULATORS &

CONTROL

Figure B-1. MDS 4800 bps Modem Block Diagram

Receive Data

While no carrier is detected, the squelch circuit in the receiver senses the lack of quieting andforces the DCD low and RXD output to mark condition. It also biases the “slicer” circuit sothat it recognizes the very first mark-to-space transition correctly once a signal is received.

MDS 05-2415A01, Rev. A APPENDIX B B-3

When an RF carrier is detected, the receiver squelch forces DCD true and the receiver re-ceives the FSK (Frequency Shift Keyed) signal just as it would any FM modulated signal.The recovered audio is fed to the modem board which determines the peak excursion of thereceived waveform in each direction. The center voltage (halfway) between these excursionsis used as a “slice” voltage for comparison with the incoming waveform. The output of thecomparator is square wave TTL data, identical to that transmitted by the remote station. Thisis then fed to U31, the interface IC on the transceiver main board. Received data is thendelivered on the transceiver’s INTERFACE connector–Pin 3.

Synchronizing Data

For asynchronous operation, the modem synchronizes to the incoming transmit data. Forsynchronous operation, the modem generates the transmit clock timing signal for use byexternal equipment. Data changes on the rising edge of the TX clock signal, and the modemsamples the data on the falling edge of the clock signal.

Table B-1. Settings for the MDS 4800 bps Modem’s Configuration Switch S1

MODEM SWITCHESSYNCHRONIZATION 1 2 3 4 5 6 7 8

Synchronous w/internal clock O O O O O O O O

Synchronous w/external clock O C O O O O O O

Asynchronous—Preferred (factory default setting) O C O C O O O O

LEGEND: C = CLOSED = ON O = OPEN = OFF

P8 P6

S1CONFIGURATION

8 1

U6

U5

OPEN

CLOSED

Figure B-2. MDS 4800 bps Modem Assembly Diagram,P/N 03-1831A01

B-4 APPENDIX B MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A C-1

APPENDIX C9600 BPS FSK MODEM



INTRODUCTION

The 03-1833A01 modulator/demodulator (modem) was designed specifically for use with theMDS 4300 Series Transceivers, allowing it to be mounted within the transceiver housing.

This modem is capable of synchronous or asynchronous operation at 9600 bits-per-second(bps). With this option mounted within the transceiver enclosure, the MDS 4310 Transceivercan still be programmed via the RS-232 connector, without the need to remove the housingcover.

SPECIFICATIONS


Data Rate: 9600 bps Synchronous or Asynchronous

INSTALLATION

The 03-1833A01 modem installs within the transceiver housing on the transceiver mainboard at jacks J6 and J8. The modem contains an eight section set-up and test switch, S1,which is used to configure the modem for operation in a number of installation arrangements.Table C-1 describes the function and recommended setting of each of these eight switchsections.

ALIGNMENT

There is no alignment of the MDS 9600 bps modem required. However, should the modembe added to a radio that previously did not have a modem, or a defective modem is replacedwith a new one, it is advisable to check the radio’s deviation and frequency setting beforereturning the radio to service. Details on setting the deviation and frequency are covered inChapter 4—Field Tests & Adjustments.

THEORY OF OPERATION

Transmit Data

CTS is factory set to go high 10 ms after transmit data is received from the external systemvia Pin 2 on the INTERFACE connector. The time period is controlled by micro-controller U16on the transceiver board, but the period is user programmable (2 to 255 ms). This data goesthrough U31 on the transceiver main board for the RS-232 configuration or through bypassjumpers in place of U31 in the TTL configuration. The transmit data is fed into the dataprocessor U6.

C-2 APPENDIX C MDS 05-2415A01, Rev. A

Level shifting and wave shaping operations within U6 cause the data to resemble a smoothaudio waveform. This waveform feeds directly into the modulation input of the digitaltransmitter.

With no scrambling, a mark (the normal resting state when no data is being sent), is sent byan alternating 10101010 pattern at 9600 bits per second. This pattern swings the transmittercarrier back and forth about the center frequency. If the TXD line goes high (continuousspace), a 0000 or 1111 pattern is transmitted. This causes the radio’s carrier frequency to be1.6 kHz offset from the center frequency for a 12.5 kHz channel. While continuous data isbeing sent, the frequency measures approximately the nominal channel frequency as ittoggles back and forth about the center frequency. In the normal configuration, the scrambleris enabled, which causes a random bit pattern regardless of whether a mark or space is beingsent. The scrambled signal is detectable by any MDS 9600 bps modem and no operatorconfiguration is required other than setting it on or off.

Receive Data

While no RF carrier is detected, the squelch circuit in the receiver senses the lack of quietingand forces the DCD low and RXD output to mark condition. The squelch output also biasesthe “slicer” circuit on the interface board so that it recognizes the very first mark-to-spacetransition correctly once a signal is received. When an RF carrier is detected, the receiversquelch forces DCD true (high) and the receiver receives the FSK (Frequency Shift Keyed)signal just as it would any FM signal. The recovered audio is fed to the modem board.

A sample of the detected receive audio is held by U3A after it passes through a low passfilter, U3B/C. This sampling takes place after the receiver squelch opens and before thereceive data signaling begins. Two comparators in U8 use this stored voltage as a reference inrecovering the data from the received audio signal. The detected data signal from U8 is fedinto U6 for reconstruction and distribution to external interface equipment through U31, theinterface IC on the transceiver main board.

Synchronizing Data

For asynchronous operation, the modem synchronizes to the incoming transmit data. Forsynchronous operation, the modem generates the transmit clock timing signal for use byexternal equipment. Data changes on the rising edge of the TX clock signal, and the modemsamples the data on the falling edge of the clock signal.

Table C-1. Settings for the MDS 9600 bps Modem’s Configuration Switch S1

SYNCHRONIZATIONCHARACTER

SIZE*MODEM SWITCHES

1 2 3 4 5 6 7 8

Synchronous w/internal clock N/A C O O O O O O O

Synchronous w/external clock N/A C C O O O O O O

Asynchronous #1 8 C O O O O C O O

Asynchronous #2 9 C O O O O C O C

Asynchronous #3 10 C O O O O C C O

Asynchronous #4 11 C O O O O C C C

* Includes start bit, stop bit, data bits & parity.

LEGEND: C = CLOSED (ON) O = OPEN (OFF)

MDS 05-2415A01, Rev. A APPENDIX C C-3

NOTEThe “Alternate” mode is required if asynchronous data hasgaps between characters that are not equal to a multiple of a bittime, or if 1-1/2 stop bits are used.

S1OPTION SELECT

SWITCHES

SYNC-ASYNCCONVERTOR

PROM

U5 U4

5 VREGULATOR

+ 10V10 VREGULATOR

+ 13V IN

RE

U7 U8 + 5V

U3D

U3C U3BDATA PROCESSOR

MODEMRX AUDIO

U6

RUS

LOW PASS FILTER

U8

DATA SLICER

TCRCETC

U7

RS-232INTERFACE

TX

AUDIO OUT

RXD

TXD

PTT

TAE

DCDU3A

SAMPLE AMP.

U9SAMPLE SWITCH

POWER REGULATORS &

CONTROL

Figure C-1. MDS 9600 bps Modem Block Diagram

P8 P6

S1CONFIGURATION

8 1

U6

U5

OPEN

CLOSED

Figure C-2. 9600 bps Modem Assembly DiagramP/N: 03-1833A01

C-4 APPENDIX C MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A D-1

APPENDIX DREMOTE MAINTENANCE MODULE



INTRODUCTION

The Remote Maintenance feature allows fine-adjustment of several important operatingparameters of an MDS 4310 Transceiver either locally with an HHT (or PC terminal), orfrom a distant location over-the-air using MDS 2000 Diagnostics and Control SystemSoftware. This software resides on a personal computer at the system control site.

The master station in the radio system also must be equipped with Remote Maintenancecompatible firmware for over-the-air diagnostics to be possible. Diagnostics over the RFchannel is accomplished using DTMF tones executed by an MDS 4100 Series “SMART”Master Station. Any MDS 4310 Transceiver on which Remote Maintenance commands are tobe executed must be equipped with a Remote Maintenance Module (P/N 03-1958A01).

The user should be aware that Remote Maintenance commands cannot be implementedduring normal data traffic. That is, normal operation of the entire radio system must stopbefore Remote Maintenance commands can be executed. All of the MDS 4310 Transceiversserved by a particular Master Station become unavailable for data exchange when RemoteMaintenance commands are invoked on any transceiver in the radio system. Use of RemoteMaintenance commands, then, should occur at times that are as non-disruptive as possible,and any affected users should be notified in advance.

The Remote Maintenance Module mounts within the housing of the MDS 4310 Transceiver.Specifically, the board mates with connectors J5 and J7 on the main transceiver board. SeeFigure D-1.

A number of general operating settings are available by connecting an MDS HHT or PCterminal to the DB-25 INTERFACE connector on the transceiver’s case. Details on thediagnostic and programming functions of the MDS 4310 are found in Chapter 3—Programming and Diagnostics.

OPERATION

The Remote Maintenance Module mediates the Remote Maintenance commands between theHHT or PC terminal and the transceiver. It interprets the control commands and sends theappropriate instructions to the transceiver. With Remote Maintenance, three importantoperating parameters can be adjusted locally, or remotely, within specified bounds. Theseparameters are: (1) transmit power level, (2) modulation deviation, and, (3) frequency offset.The following parameters can be read, but not adjusted using Remote Maintenance: RemoteUnit Temperature, Reflected RF Power, Supply Voltage, and Received Signal Strength.

D-2 APPENDIX D MDS 05-2415A01, Rev. A

NOTEAn alternative to the HHT is a personal computer running aterminal program, such as PCPLUS™, PROCOMM™,PCTALK™, etc. connected to the radio’s INTERFACEconnector. In this case, the program should be set to 1200 bps,eight data bits, parity-none and one stop bit. The keyboardmust be set with the caps lock key pressed, as the radioresponds only to commands made in uppercase characters.

Remote Maintenance gives remote access for fine adjustment but does not allow adjustmentof these parameters over the entire range of adjustment of which the radio is capable. Forexample, Remote Maintenance allows you to correct the operating frequency of a radio thathas drifted away from its specified rating but it does not allow you to change the operatingfrequency to a different channel altogether. Nor is Remote Maintenance a substitute forperiodic or demand-based field maintenance and re-alignment. Instead, it is a means ofkeeping the radio at optimal performance without having to visit the radio site in person.

MODULE ADJUSTMENTS & CALIBRATION

The Remote Maintenance Module contains two adjustable controls—Loopback TX AudioLevel (R6), and Temperature Setting (R33). Normally, R6 needs adjustment only when themodule is first installed in the radio. R33 is adjusted at the factory. Refer to Chapter 4—Field Tests and Adjustments, Test Procedure ➏ for alignment instructions.

NOTEIn a properly aligned system, Remote Maintenance providesvaluable information to service personnel, however, it shouldnot be considered a replacement for calibrated test equipment.

R6LOOPBACK TX AUDIO LEVEL

J7 J5

R33TEMP. SET

Figure D-1. Remote Maintenance Module, P/N 03-1958A01

DETERMINING THE PRESENCE OF A REMOTE MAINTENANCE MODULE

Radios with a Remote Maintenance Module installed at the factory will have a label on thecase’s exterior identifying the unit’s loopback code. The presence of this label indicates thatthe Remote Maintenance Module is probably installed. However, it is possible that a RemoteMaintenance Module was installed after the radio was shipped from the factory, or that theassembly was removed from the radio. Even though it is impossible to confirm the physicalpresence of the module from outside the case, it is possible to test its presence through theuse of the HHT or PC terminal.

MDS 05-2415A01, Rev. A APPENDIX D D-3

If you are unsure whether a Remote Maintenance Module is installed in the transceiver, openthe Diagnostics Channel and enter the STAT command. The display responds with the type ofdiagnostics that are installed in the transceiver. The forth character will be I for “installed”, orU for “uninstalled.” The other characters describe additional details about the radio’sconfiguration. Refer to Table 3-2 for a complete listing of the STAT characters.

NOTEIf a Remote Maintenance Module is installed while the poweris on, the transceiver will show that the board is NOT installeduntil the DC power to the radio is shut off for at least five (5)seconds, and then turned back on.

INSTALLATION & REPLACEMENT

Normally, the installation of the Remote Maintenance Module is done at the factory; the onlyfield activities are the programming of the loopback code, setting the diagnostics deviation,and the removal and replacement of a defective assembly. This section describes the installa-tion and removal of the Remote Maintenance Module. Refer to Chapter 4—Field Tests andAlignments, Test ➏ for instructions on setting the loopback code and for adjusting the diag-nostics deviation.

Physical Installation/Removal

The following procedures summarize the removal and replacement of a Remote MaintenanceModule.

To remove the module:

1. Disconnect primary power to the unit and remove the transceiver’s top cover.

2. With a slight rocking motion, remove the module from the Option 2 position (JacksJ5 and J7) on the main transceiver board.

To install the module:

1. Disconnect primary power to the unit and remove the transceiver’s top cover.

2. Plug the module into the Option 2 position (Jacks J5 and J7) on the transceivermotherboard.

3. Make sure connectors are fully mated, and there are no bent pins that might preventproper connector seating or module operation.

4. Re-apply primary power and test the system for normal operation.

5. With the HHT or PC terminal, use the STAT command to verify the presence of themodule (see Determining the Presence of a Remote Maintenance Module, in thepreceding subsection), then program in the unit’s loopback code, set the diagnosticlevel (Mode 1, 2 or 3) and check the transmit modulation level. In addition, if theinstallation is a field upgrade, then Test Procedure ➏ in Chapter 4 must be followed.


NOTEOnce a loopback code has been entered, typing the L B Ccommand results in a display of the code, followed by the letterI to indicated that it is “Installed.” If a loopback code has notbeen programmed, the letters UI for “Uninstalled” will bedisplayed, even if the module is present, since a valid code hasnot been entered. Once the loopback code is entered and theradio is shut down and re-powered up, the indicator will be Ifor “Installed.”

TESTING THE LOOPBACK CODE

This section presents three basic test options to verify that the transceiver is respondingproperly to its programmed loopback code. Chapter 4—Field Tests and Adjustments, TestProcedure ➏ covers procedures for programming a new loopback code.

The Remote Maintenance Module receives instructions over-the-air in the form of DTMFsignals from the system’s master station. Outgoing data from the Remote MaintenanceModule is also modulated with DTMF signals.

Local Testing with a DTMF Encoder

A programmable DTMF encoder with an audio level output of –10 dBm can be attached toPin 22 of the INTERFACE connector J1 to emulate incoming DTMF polling signals from thesystem’s master station. The radio’s four digit loopback code can then be sent through J1-Pin22 to the Remote Maintenance Module.

A properly decoded Loopback Code will key the radio and generate a series of DTMF signalsand a short, but steady, tone that is used by the master station for frequency and deviationmeasurements. This basic response can be monitored on a communications service monitor.Make sure to connect the ANTENNA jack of the transceiver to the transmit input of the servicemonitor before starting the test.

Local Testing with a Communications Service Monitor

Many communications service monitors are capable of providing sequential DTMF encodingon their RF test signals. Connect the transceiver to the monitor’s internal dummy load andprogram the encoder to generate the four digit loopback code sequence as an on-channelDTMF signal. Monitor the response from the transceiver as previously discussed.

Remote Testing with a “SMART” Master Station

With the radio installed in the system and the master station connected to a personalcomputer running the MDS 2000 Diagnostic & Control System software, poll the remotestation using its loopback code. The appropriate diagnostic information should be displayedon the PC screen. Review the software operating instructions for details.

TROUBLESHOOTING

If the Remote Maintenance Module does not respond to a four digit DTMF loopback code,verify the installation and basic operation of the assembly by following this procedure.

1. Connect the HHT or ASCII terminal to the transceiver as previously described.


Radio RF TX Power Control

U10 is a 100-position 100k EEPOT that controls the radio’s RF TX power. U10 is configuredas a ratiometric resistor that sources a voltage to control the transmitter power. The voltagebeing sourced by the EEPOT is controlled by the micro-controller on the transceiver’s maincircuit board. The setting is controlled by the firmware through the diagnostics channel, bothlocally and remotely.

Radio Center Frequency Control

U9 is a 100-position 100k EEPOT that controls the radio carrier frequency. U9 is configuredas a ratiometric resistor that sources a voltage to control the carrier frequency. The voltagebeing sourced by the EEPOT is controlled by the micro-controller on the transceiver’s mainPC board. The setting is controlled by the firmware through the diagnostics channel, bothlocally and remotely.

MDS 05-2415A01, Rev. A E-1

APPENDIX EORDER WIRE MODULE


Kit P/N: 02-1297A01

INTRODUCTION

The Order Wire Module (Figure E-1) is an optional adapter for the MDS 4310 Transceiverwhich makes two-way voice communications possible for the initial set-up and testing of theradio link. If the Order Wire Module is connected between the transceiver and the RTU, anda telephone handset is plugged into the Order Wire Module, it is possible to listen to the datacommunications on the channel. Receiver audio from the transceiver can be monitored byusing the earpiece on the handset. Speaking into the handset microphone activates the VOXcircuit in the adapter, allowing voice communications with the master or base station.

As a convenience, the Order Wire Module has been designed to work with a standard four-wire modular (RJ-11-4) telephone handset, available from any telephone supply store orelectronic parts distributor.

ORDER WIRE MODULE

Female connector

Male connector Radio

RTU

MALE CONNECTORTO RADIOP/N 03-1295A02

FEMALE CONNECTORTO RTU OR MODEMP/N 03-1294A01

TRANSMIT INDICATOR (LED)

HANDSETPHONE JACK

Figure E-1. Order Wire Module

E-2 APPENDIX E MDS 05-2415A01, Rev. A

THEORY OF OPERATION (Refer to Figure E-2 and Figure E-3)

Microphone audio is first pre-emphasized by C-1 and R5. R4 provides current for the carbonmicrophone typically used in telephone handsets. U1A amplifies and limits the microphoneaudio, with R17 setting the VOX microphone gain. R19 sets the deviation and is normally setfor –10 dBm output to the transmitter. Solid state switch U2 automatically switches betweenthe handset audio and the external RTU or modem audio in response to the VOX circuit builtinto the adapter. When the limiter is driven into limiting, audio is present at U1 Pin 2. CR1detects this audio, with C5 and R12 providing a VOX delay.

As long as the microphone audio is below clipping level, U1 Pin 2 remains a virtual groundand PTT remains low. U1D amplifies the received audio, with R18 setting the volume. R13couples some of the TX audio into this amplifier to provide “sidetone” for the handset (soyou can hear yourself talk in the earpiece, just as with a regular telephone). R16 and C4provide de-emphasis for the received audio.

U1

U2

R17

R18

R19C7

C6

C5 C8

J1 J2

C11

C10

C9

CR4

J3

+

+

+

+

+

+ +

R2

R1

R11R4

R9

R7

R8

R10

CR

3C

R2

R15

R14

CR

1R

12

R5

R3

C2

C1

C3

C4

R6

R13R16

Figure E-2. Order Wire Board Component Layout

E-4 APPENDIX E MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A H-1

APPENDIX HMDS 4310-HL DATA TRANSCEIVER

FOR USE IN HAZARDOUS LOCATIONS

INTRODUCTION

The MDS 4310-HL Data Transceiver is available for use in Class I, Division 2, Groups A, B,C, and D Hazardous Locations. Such locations are defined in Article 500 of the National FireProtection Association (NFPA) publication NFPA 70, otherwise known as the NationalElectrical Code.

The MDS 4310-HL Data Transceiver has been recognized for use in these hazardouslocations by two independent agencies —Underwriters Laboratories (UL) and FactoryMutual Research Corporation (FMRC). The UL certification for the transceiver is as aRecognized Component for use in these hazardous locations, in accordance with ULStandard 1604. The FMRC Approval is in accordance with FMRC Standard 3611.

CONDITIONS OF APPROVAL

The MDS 4310-HL Data Transceiver is not acceptable as a stand-alone unit for use in thehazardous locations described above. It must either be mounted within another piece ofequipment which is certified for hazardous locations, or installed within guidelines, orconditions of approval, as set forth by the approving agencies. These conditions of approvalare as follows:

1. The transceiver must be mounted within a separate enclosure which is suitable forthe intended application.

2. The antenna feedline, DC power cable and interface cable must be routed throughconduit in accordance with the National Electrical Code.

3. Installation, operation and maintenance of the transceiver should be in accordancewith the transceiver's installation manual, and the National Electrical Code.

4. Tampering or replacement with non-factory components may adversely affect thesafe use of the transceiver in the hazardous locations, and may void the approval.

Refer to Articles 500 through 502 of the National Electrical Code (NFPA 70) for furtherinformation on hazardous locations and approved Division 2 wiring methods.

H-2 APPENDIX H MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A I-1

APPENDIX ICANADIAN CERTIFICATION

RSS APPROVALS

The MDS 4310 Transceiver has been approved for use in Canada under Radio StandardsSpecification (RSS) 119 and 122 of Industry Canada (IC) certification. The frequency rangesand channel spacings for this application are as follows:

RSS-119

Frequency Range: Transmit —406.1–430, 450–470 MHz

Receive —406.1–430, 450–470 MHz

Channel Spacing: 25 kHz

Power Output: 1 to 5 watts, continuously variable

RSS-122

Frequency Range: Transmit —406.1–430 MHz

Receive —406.1–430 MHz

Channel Spacing: 12.5 kHz

Power Output: 1 to 5 watts continuously variable

RESTRICTIONS

The Industry Canada approval is valid subject to the restrictions listed below:

1. The MDS 4310 may only be used with a built-in modem at speeds of either 1200,4800 or 9600 bps. No external modems or other signaling devices using externaltransmit audio input (Pin 9 of the INTERFACE connector) are permitted.

2. The Order Wire Module (MDS P/N 02-1297A01) may not be used with thetransceiver.

I-2 APPENDIX I MDS 05-2415A01, Rev. A


MDS 05-2415A01, Rev. A J-1

APPENDIX JAUDIO PROCESSING MODULE



INTRODUCTION

The Audio Processing Module is used in applications where no method of keying the remotetransceiver is provided by the RTU or modem. The assembly senses the presence of an audiotone on the transmit audio line and, in turn, keys the transmitter. This function is typicallycalled a VOX function. When installed in the MDS 4310 Transceiver, the Audio ProcessingModule is mounted in the Option 1 position on the main transceiver board. See Figure J-3.

Figure J-1 and J-2 show the component layouts for the Audio Processing Modules. Theboards contain an array of switches to configure the assembly for a variety of interfacerequirements. The assemblies consist several circuits—a VOX circuit (discussed above), atransmit audio pre-emphasis circuit, receive audio de-emphasis circuit and limiter circuitry.These circuits may be turned on and off independently using the configuration switches.

The automatic level control (ALC) circuitry is continuously enabled and provides the correctaudio level for the transceiver. The audio input level should be between -30 and 0 dBm.

OPTION 1—Modem PC Assembly orAudio Processing Module

OPTION 2—Remote Maintenance Moduleor Diagnostic & Loopback Module

TRANSCEIVERPC BOARD

Figure J-1. Audio Processing Module Installation Diagram

SPECIFICATIONS

Power Requirements: +10 Vdc @ 1 mA standby; 8 mA activated

Key-up Time: Less than 2 milliseconds; 0.25 ms typical

Release Time: Less than 10 milliseconds; 5 ms typical

J-2 APPENDIX J MDS 05-2415A01, Rev. A

ALIGNMENT

There are no adjustments required on the Audio Processing Module. However, when themodule is installed in a radio that was previously aligned for use with a modem, two adjust-ments need to be made on the transceiver motherboard —Receive Audio and TransmitDeviation. Refer to Chapter 4—Field Tests and Adjustments, Test Procedure ➋, for adjust-ment procedures.

CONFIGURATION

Tables J-1 and J-2 list various functions of the DIP switch on the PC board. Theconfiguration chosen for some functions, such as the filtered/flat response depends on thespecific requirements of your system. If technical assistance is required, contact MDS,Systems Engineering Department.

NOTEWhen the VOX Function is used in an MDS 4310 Transceiver,the Squelch Tail Eliminator (STE) circuitry on the transceiver’smotherboard should be turned off. The status of this operatingparameter can be checked, and if necessary set to OFF, usingthe Hand-Held Terminal (HHT). For more information onusing the HHT, see Chapter 3—Programming and Diagnostics,especially the section “Programming Examples” and Table 3-2.

Table J-1 lists the configuration switch settings for the MDS P/N 03–2301A01. Figure J-2shows the component layout for the PC board.

C31

U3

R22C15

R38

P8

C26

C12

R19

C29

CR2

CR1

R13

C27MICROWAVE DATA SYSTEMS

R12

C30

C23

U2

C17

R41

C6

R6VOX 4000 PCBC24 C20

U7

C7

R11

R25

R24

C28

R3

C1

C2

R45

R1

R36

R4

C22

R26

R16

R17

R18

R5

U6

R33

CR4

CR3

C11

C9

R10

R14

R15

U8

C18

R44

R9

C14

R43

R8

TXFILTRXAUDLIMITDEEMPHPREEMPVOXRXFILTENABLE

P6

U4

R21

R48

C3

R2

R7

C4

C25

C5

R20

R23

R46

C8

R47

R30

C21

R29

C10

C13

R31

R27

R28

C19

U1

12345678

ON

Figure J-2. 03-2301A01 Audio Processing Module

Table J-1. P/N 03–2301A01 Configuration Switch Settings

SWITCH POSITION

FUNCTION SW1 OFF ON

Filtered/Flat TX Audio 1 No VOX Keyline VOX Keyline

RX Audio Enable 2 Filtered Flat

Limiter ON/OFF 3 No TX Limiter TX Limiter

De-Emphasis ON/OFF 4 No De-Emphasis De-Emphasis

Pre-emphasis ON/OFF 5 No Pre-Emphasis Pre-Emphasis

VOX Enable 6 VOX Disabled VOX Enabled

Filtered/Flat RX Audio 7 Filtered Flat

TX Audio Enable 8 No Processing Processing

In Case of Difficulty...The MDS 4310 Transceiver is designed for long life and trouble-free operation. However,this equipment, as with all electronic equipment may have an occasional component failure.The following information will assist you in the event that servicing becomes necessary.

Factory Technical Assistance

Technical assistance for MDS products is available from our Systems Engineering Groupduring business hours (8:30 A.M.–5:00 P.M. EST). When calling, please give the completemodel number of the radio, along with a description of the trouble symptom(s) that you areexperiencing. In many cases, problems can be resolved over the telephone, without the needfor returning the unit to the factory.

Please use the following telephone numbers for product assistance:

716-242-9600 (Phone)716-242-9620 (FAX)

Factory Repairs

Component level repair of the transceiver is not recommended in the field. Many transceivercomponents are installed using surface mount technology, which requires specialized trainingand equipment for proper servicing. For this reason, the equipment should be returned to thefactory for any PC board repairs. The factory is best equipped to diagnose, repair and alignyour radio to its proper operating specifications.

If return of the equipment is necessary, you will be issued a Returned Material Authorization(RMA) number. The RMA number will help expedite the repair so that the equipment can berepaired and returned to you as quickly as possible. Please be sure to include the RMAnumber on the outside of the shipping box, and on any correspondence relating to the repair.No equipment will be accepted for repair without an RMA number.

A statement should accompany the radio describing, in detail, the trouble symptom(s), and adescription of any associated equipment normally connected to the radio. It is also importantto include the name and telephone number of a person in your organization who can becontacted if additional information is required.

The radio must be properly packed for return to the factory. The original shipping containerand packaging materials should be used whenever possible. All factory returns should beaddressed to:

Microwave Data SystemsCustomer Service Department(RMA No. XXXX)175 Science ParkwayRochester, NY 14620 USA

When repairs have been completed, the equipment will be returned to you by the sameshipping method used to send it to the factory. Please specify if you wish to make differentshipping arrangements.

Mds-4310 Radio Transceiver

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