3Com U.S. Robotics

3Com U.S. Robotics

56K Message Modem

User’s Guide & Reference

This manual covers installation and operating instructions for thefollowing modem:

• 3Com U.S. Robotics 56K Message Modem external modem

IMPORTANT MESSAGE: In accordance with the ITU-I standard for56K transmissions, this modem is capable of 56Kbps downloads.However, the download speeds you experience may be lower due tovarying line conditions and other factors. Uploads from users to serverequipment travel at speeds up to 31.2 Kbps. An analogue phone linecompatible with the ITU-T 56K standard (V.90) or x2 technology, andan Internet provider or corporate host site with the ITU-T 56K standard(V.90) or x2 technology are necessary for these high-speed downloads.Visit our Web site at http://www.3com.co.uk for future updates andenhancements.

3Com, the 3Com logo, and U.S. Robotics are registered trademarksand Total Control, Courier, x2 and the x2 logo are trademarks of 3Com

Corporation or its subsidiaries. Windows is a registered trademark ofMicrosoft Corp. Any other trademarks, trade names, service marks, orservice names owned or registered by any other company and used in

this manual are the property of their respective owners.

© 1999 3Com Corporation220 Wharfdale Road

WinnershWokingham

Berkshire RG41 5TPAll Rights Reserved

P/N: 2.024.288-A

Table of Contents

WELCOME TO 56K* INFORMATION ACCESS..................................1

PRODUCT FEATURES........................................................................2

FAX STANDARDS .................................................................................2

SUMMARY OF FEATURES .................................................................4

REMOTE VOICE RETRIEVAL ..................................................................7TELEPHONE HANDSET DTMF DIGITS FOR REMOTE MESSAGE RETRIEVAL .8INDEPENDENT MODE FACSIMILE (FAX) FORWARDING...............................8CALLER ID FEATURE (APPLIES IN THE UK ONLY).....................................9

PART I : EXTERNAL MODEM INSTALLATION ................................10

SECTION A: EXTERNAL MODEM INSTALLATION WITH WINDOWS 3.X .........10How to Connect the Modem.........................................................11

SECTION B : EXTERNAL MODEM INSTALLATION WITH WINDOWS 95.........12How to Move Through the Screens You See When WindowsRestarts .......................................................................................15

PART II : BEYOND SETUP................................................................22

SECTION A: INSTALLING VOICE/FAX/DATA SOFTWARE .........................23Type of Modem............................................................................23Initialisation String........................................................................23Flow Control ................................................................................24UART - Universal Asynchronous Receiver Transmitter.................24(External Modems Only) ..............................................................24

SECTION B : TROUBLESHOOTING AND ONLINE HELP RESOURCES ...........25If Plug and Play Does Not Detect Your Modem ............................31Online Help Resources..............................................................32Are You Still Having Problems? ...............................................34

SECTION C : GLOSSARY ....................................................................35SECTION D : TECHNICAL QUICK REFERENCE........................................45

Basic Data Commands ................................................................48S-Registers..................................................................................58The Serial Interface......................................................................68

SECTION E : CE COMPLIANCE............................................................69Electromagnetic Compatibility ......................................................69Safety (Low Voltage Directive) .....................................................69CTR 21 Approval .........................................................................70Network Compatibility Declaration................................................70

SECTION F : LIMITED WARRANTY........................................................71

User’s Guide 1

Welcome to 56K*Information Access

The International Telecommunications Union (ITU) decides thetechnical protocols communications devices must use to interoperatewith each other. Modems that comply with ITU standards can “talk to”other standards-compliant modems and fax machines worldwide.

The ITU has decided on a worldwide 56K standard technology. So, nowwith a U.S. Robotics modem you can get all the Internet you want fromany service provider who offers the V.90 ITU standard 56K technologyor x2™ technology.

This modem will give you the most compatibility with high speeddownloads from service providers that offer the ITU 56K standardtechnology or x2 technology to their customers. 3Com U.S. Robotics isworking with providers everywhere to quickly upgrade their service tothe V.90 ITU 56K standard.

∗ Capable of receiving up to 56 Kbps and sending up to 31.2 Kbps.

∗ The download speeds you experience may be lower due to varyingline conditions and other factors.

∗ Actual speeds may vary.

∗ Requires compatible phone line and server equipment.

∗ Complies with both the proposed V.90 ITU 56K standard and x2protocols.

∗ See www.3com.com/56k.

2 56K Message Modem

Product Features

Your 56K Message Modem provides many advanced features. Here arejust a few :

Modulation SchemesITU-T V.90 56K standardx2 Technology (Download up to 56kbps, and Upload at 31,200bps)ITU-T V.34 (Inc. 33,600 and 28,800bps)ITU-T V.32bisITU-T V.32ITU-T V.22bisITU-T V.22ITU-T V.23ITU-T V.21Bell 212ABell 103

Error Control and Data Compression SchemesITU-T V.42ITU-T V.42bisMNP 2-5

Fax Modulation SchemesITU-T V.17ITU-T V.29ITU-T V.27terITU-T V.21

Fax StandardsEIA 578 Class 1 FAXEIA 592 Class 2.0 FAX

User’s Guide 3

Front Channel Link Rates (Download Speeds)28000, 29333, 30666, 32000, 33333, 34666, 36000, 37333, 38666,40000, 41333, 42666, 44000, 45333, 46666, 48000, 49333, 50666,52000, 53333, 54666, 56000, 57333

Back Channel Link Rates (Upload Speeds)4800, 7200, 9600, 12000, 14400, 16800, 19200, 21600, 24000, 26400,28800, 31200

V.34 Link Rates4800, 7200, 9600, 12000, 14400, 16800, 19200, 21600, 24000, 26400,28800, 31200, 33600

V.32bis Link Rates4800, 7200, 9600, 12000, 14400

Additional Link Rates300, 1200/75 (V.23), 1200, 2400

Fax Link Rates2400, 4800, 7200, 9600, 12000, 14400

4 56K Message Modem

Summary of Features

Key Features of 56K Message Modem56K Message Modem is the first product to include features that allowthe user to receive fax and voice messages without the intervention ofthe PC. 56K Message Modem features a bank of Flash Memory for thispurpose. Messages can be received even when the PC is not switchedon. Voice messages can be retrieved from a remote location.

56K Message Modem comes with specially designed applicationsoftware. This product is not just a normal voice/fax/data modem.The software includes all features needed to manage both 56KMessage Modem in autonomous (independent) mode and normalfax and voice message mode.

56K Message Modem---

• is a feature-enhanced external modem with added Flash Memory. • provides the full functionality of a standard modem. • retains incoming fax and voice messages and therefore is not just a

pass through device. • is capable of receiving and storing incoming fax and voice

messages without any DTE (Data Terminal Equipment) interventioni.e. without a computer being switched on.

• can transfer stored messages to the DTE (Data Terminal

Equipment) at a later time. • enables remotely stored voice messages to be accessed through a

dial-up connection.

User’s Guide 5

• offers a voice channel feature that includes a built-in condensermicrophone.

• includes software designed specifically for use with 56K MessageModem. The software allows the user to take full advantage of allfeatures in the product. Other software can be used for all standardmodem functions. In order to use the autonomous features,however, we recommend using the software delivered with theproduct.

Before You BeginFrom the factory, autonomous (independent) mode is not enabled.Therefore, it is necessary to configure the Message modem using thesupplied communication software to make full use of these features.Independent fax and voice functionality can be enabled using theappropriate ‘Independent Mode’ screen of the supplied software. Also,you will need to set a password for use with the remote feature of themodem. Refer to the software package to choose your 4-digitpassword.

It is also necessary to record a Personal Greeting Message and FullMessage to use with the Message modem Modem. The followingsection provides full instructions of how to achieve this.

Personal MessageYour personal message can be recorded using the supplied softwareapplication.

1. Within the Independent Mode Greeting Screen, click Record, andrecite your personal message.

Note: If the recording limit of 15 seconds is reached, the recording

will stop and a dialogue window will display a warning message.

2. Click Stop when you have finished.

3. To listen to your message, press PLAY from the supplied softwareapplication.

6 56K Message Modem

4. Once you have recorded your Personal Message, click on the‘Download’ button in order to send your Personal Message to themodem.

Full MessageYour full message can be recorded using the supplied softwareapplication.

1. Within the Independent Mode Message Full Screen, click Record,and recite your Full Message.

Note: If the recording limit of 15 seconds is reached, the recordingwill stop and a dialogue window will display a warning message.

2. Click Stop when you have finished.

3. To listen to your message, press PLAY from the supplied softwareapplication.

4. Once you have recorded your Full Message, click on the 'Download'button in order to send your Full Message to the modem.

User’s Guide 7

Remote Voice Retrieval

- whilst the modem is in Independent mode -

To access your Voice messages remotely, you need to dial into the 56KMessage Modem modem. Whilst the 'outgoing message' is beingplayed, you must enter your pre-configured password on a touch-tonetelephone handset (this can be set using the software application).

You have three attempts to enter the correct password. If you fail toenter the correct password, the modem will 'abort' the call and go back'on hook'.

If the correct password is entered, the modem will either emit,

i) a series of short 'beeps' indicating the number of unreadmessages or,

ii) one long 'beep' indicating there are no read/ unread messages.

The user has the option to press:

0 for a repeated acoustic message count

1 to play unread messages

2 to play read messages

At any time the user may abort the call by pressing the * key.The modem will automatically hang-up after a period of in-activity.

8 56K Message Modem

Telephone Handset DTMF Digits forRemote Message Retrieval

Digit(s) Function-------------------------------------------------------------------0 1) Stops playback of all voice messages

2) Stops the recording of your personal message3) Stops playback of your personal message

1 Starts playback of all new messages

2 Starts playback of all stored messages, new and old

3 Skips to the next voice message

4 then 4 Deletes all old voice messages in memory

5 Enables/Disables Fax Forwarding feature

6 Repeats the current voice message

7 Records the personal message

8 Not utilized

9 Repeats the new message count

* Hangs up the modem# Not utilized

Independent Mode Facsimile (Fax)Forwarding

Faxes can be forwarded to a predefined phone number. Thefaxes will continue to be forwarded until the feature is disabled.The faxes can be redirected to a different number at any time bychanging the predefined number through the softwareapplication. The Independent mode fax forwarding feature iscontrolled through the software application or remotely.

User’s Guide 9

1) Setup Independent Fax modeSet the phone number in the application (number is stored inthe flash memory of the modem) and then enable/disableusing the applicable button.

2) Fax forwarding dial up control (remote control is limited only to the enable/disable feature as

follows)

a) Enter your password and from the Main menu, press ÄÄto toggle the enable/disable fax forwarding feature.

b) Confirmation of the enabling/disabling of this featurewill be indicated by playing an opening/closing tone.

Caller ID Feature (applies in the UK only)The Caller ID feature discloses the identification of the callerprior to answering the call. You can enable/disable this featurethrough the software application and are then able to view thecalling telephone number from within a dialing window.Messages retrieved from Independent mode will be stored withidentification within the software mailbox.Caller ID must be subscribed from your telephone provider andneeds to be compatible with the British Telecom Caller IDsystems before this feature can be utilised.

#CID=n Controls Caller ID feature#CID=0 Caller ID disabled#CID=1 Caller ID enabled with formatted information#CID=2 Caller ID enabled with unformatted information

10 56K Message Modem

Part I : External ModemInstallation

Part I of this manual covers the installation of your external 56KMessage Modem. The instructions are provided for both Windows 3.1/3.11 (hereafter jointly referred to as Windows 3.x) and Windows 95users. Please refer to the section dealing with the operating system youuse.

The two sections are:

Section A: External Installation with Windows 3.x (page 10)

Section B: External Installation with Windows 95 (page12)

Section A: External Modem Installationwith Windows 3.x

You’ll need these items from your 56K Message Modembox:

modem phone lead & adapter

manual serial cable power adapter& serial adapter

User’s Guide 11

How to Connect the Modem

1. Turn off your computer and any attached devices, such as a printer.

2. Connect the serial cable to the modem and to the computer. Whenlooking for the serial port label on the back of your computer, lookfor ports labelled COM, MODEM, RS-232, or SERIAL. DO NOTselect AUX, GAME, LPT, or PARALLEL.

NOTE: Remember which serial port you selected. Thisinformation will be necessary when installing your communicationssoftware.

3. Plug the power adapter into the power socket on the modem andinto a standard wall outlet.

4. Plug one end of the phone lead into the modem telephone socket. Itis labelled with a wall plug icon on the bottom of the case. Plug theother end into a phone wall socket.

WARNING: The phone socket you use must be for anANALOGUE phone line. Most office phones are wired throughDIGITAL lines. Be sure you know what type of line you have.The modem will be damaged if you use a digital phone line.

5. If you wish to use your modem and phone through the same phonewall socket, plug your phone's lead into the modem's phone socket.It is labelled with a phone icon on the bottom of the case. Use anadapter cable if necessary.

NOTE: You cannot use the modem and phone at the same time if theyare sharing a line.


6. Turn your modem on.7. Turn your computer on.8. Start Windows 3.x.

Congratulations! You are ready to start using your 56K MessageModem.

Section B : External Modem Installationwith Windows 95

You will need these items from your 3Com U.S. RoboticsMessage Modem box:

modem phone cord

power adapter serial cable

User’s Guide 13

How to Find Out Which Version of Windows 95 You Have

1. With the right mouse button, click the My Computer icon on yourdesktop.

2. Click Properties.In the “System Properties” screen, look at the system informationunder the General tab. (This information is circled in the screenshown to the right.)

The number following the text “Microsoft Windows 95” will end with“950,” “950a,” or “950b.” This indicates your version of Windows 95.

3. Write this number down for later reference.

4. Click OK.

How to connect the Modem to the Computer

1. Turn off your computer and any attached devices, such as a printer.2. Connect the serial cable to the modem and to the computer. When

looking for your serial port label on the back of your computer, selectCOM, MODEM, RS-232, or SERIAL..

DO NOT select AUX, GAME, LPT, or PARALLEL.

Note: Remember which serial port you selected. This informationwill be necessary when installing your communications software.

3. Plug the power adapter into the modem power socket and into astandard wall outlet.

4. Plug one end of the phone lead into the modem telephone socket. Itis labelled with a wall plug icon on the bottom of the case. Plug theother end into a phone wall socket.


WARNING: The phone socket you’re going to use must be for anANALOGUE phone line. Most office phones are wired throughDIGITAL lines. Be sure you know what type of line you have.The modem will be damaged if you use a digital phone line.

5. If you wish to use your modem and phone through the same phonewall socket, plug your phone's lead into the modem's phone socket.It is labelled with a phone icon on the bottom of the case. Use anadapter cable if necessary.

NOTE: You can not use the modem and phone at the same time ifthey share the same line.

6. Turn your modem on.7. Turn your computer on.8. Start Windows 95.

User’s Guide 15

How to Move Through the Screens You See WhenWindows Restarts

If you have Windows 95 Version 950 or 950a:

1. When Windows 95 restarts, it should detect the modem. If it does,you will see the following screen.

Click Driver from disk provided by hardware manufacturer.Then click OK.

NOTE: If this screen does not appear, go to “If Plug and PlayDoes Not Detect Your Modem”.

2. Insert the driver disk into your disk drive.3. When you see this screen, type in A:\

If your disk drive is a different letter, type that letter instead of A.

Click OK. Windows will install the drivers for your new modem.


4. You can verify that the install was a success. When your desktopreturns, click the Windows Start button and point to Settings.

5. Click Control Panel.

6. Double-click the Modems icon.

User’s Guide 17

7. In the “Modems Properties” screen, you should see a description foryour modem. This indicates that your new 3Com U.S. RoboticsMessage Modem is installed correctly.

Note: If this screen does not appear, go to “If Plug and Play DoesNot Detect Your Modem”.


8. Next, click the Diagnostics tab at the top of the “ModemsProperties” screen. Write down the COM port number for yourmodem. You will need to know this setting when you installyour communications software.

9. Click OK.

If You Have Windows 95 Version 950b:

1. When Windows restarts, it should detect the modem, and youshould see a screen like the one below.

Insert the driver disk into your disk drive and click Next.


2. When you see the following screen, click Finish.

User’s Guide 19

3. Once Windows finishes loading the information from the disk, youshould verify that the modem installation was a success. When yourdesktop returns, click Start and point to Settings. Then clickControl Panel.

4. Double-click the Modems icon.


5. In the “Modems Properties” screen, you should see a description ofyour modem. This indicates that your new 3Com U.S. RoboticsMessage Modem is installed correctly.


User’s Guide 21

6. Next, click the Diagnostics tab at the top of the “ModemsProperties” screen. Write down the COM port number for yourmodem. You will need to know this setting when you install yourcommunications software.

7. Click OK.

Congratulations! You are now ready to start using your 3Com U.S.Robotics Message Modem.


Part II : Beyond Setup

Part II includes information which may not be necessary for installingyour modem or voice/fax/data software, but will help to expand yourknowledge of the modem and its capabilities. The five sections are:

Section A: Installing Voice/Fax/Data Software (page 23)

Section B: Troubleshooting and Online Help Resources (page 25)

Section C: Glossary (page 35)

Section D: Technical Quick Reference (page 45)

Section E : CE Compliance (page 69)

Section F : Limited Warranty (page 71)

User’s Guide 23

Section A: Installing Voice/Fax/DataSoftware

Your modem has been designed and tested using a wide range ofcommunications software packages on the market. This section willwalk you through some of the details you may need to know wheninstalling communications software packages.

Type of ModemMost communications software programs will ask you to select the typeof modem you are using. Select a 3Com brand high speed modem. Ifthat selection is not listed, pick Courier Dual Standard, V.32bis, or V.34.

KEY POINT: Refer to the manual that came with your softwarefor its installation instructions. The software’s installationprogram will ask you questions about the modem you are using.

Initialisation StringFor hardware flow control, a fixed serial port rate and full result codestype:

AT&F1<Enter>

If you must use software flow control, type:

AT&F2<Enter>


Flow Control• For hardware flow control (highly recommended), select RTS/CTS.

• For software flow control, select XON/XOFF.

NOTE: Disable the type of flow control (hardware or software) thatyou are not using.

UART - Universal Asynchronous Receiver Transmitter

(External Modems Only)If you are running Windows 3.x or you have upgraded your system fromWindows 3.x to Windows 95, you can run MSD to determine yourUART setting. In DOS, type MSD at the Windows directory prompt andthen press ENTER. Follow the on-screen instructions to access theCOM port settings panel. In this panel you should find the UART chipused. Match the UART type listed in MSD with the serial rate listed inthe chart below. Select this serial rate (sometimes called the “port rate”)in any communications software you use.

If this is your UART... Select this serial rate

16550 115.2 or 57.6 Kbps

16450 38.4 Kbps

8250 19.2 Kbps

NOTE: DO NOT select a 28,800, 14,400, or 12,000 bpsserial port rate if offered. Your modem will NOT work correctlywith any of these settings. Fix or lock the serial port (baud) rate.If it’s referred to as autobaud, select OFF.

User’s Guide 25

Section B : Troubleshooting and OnlineHelp Resources

PROBLEM DIAGNOSIS POSSIBLE SOLUTIONThe computer orsoftware will notrecognize themodem.

You may not be enteringmodem commands in theproper manner in Terminalmode.

If you are using an externalmodem, the COM port maynot be enabled.

You may have a COMport/IRQ conflict.

Type in all upper case (AT) or alllower case (at).

Refer to the computer’s manual forinformation about enabling COMports. This usually involves alteringthe bios settings, motherboardjumpers, and the operating system.

Make sure you have the correctCOM port and IRQ settings in yoursoftware and/or in the WindowsDevice Manager.

The modem will notgo off hook to dial ordoes not answer thephone.

You may have plugged yourmodem’s phone cord intothe wrong socket on themodem.

The phone jack may havebeen wired incorrectly.

You may have a bad phonecord connection to yourmodem.

Make sure the phone cord isplugged into the modem socketlabeled with a wall plug icon.

Contact the telephone company.Ask them to make sure the tip andring are on the outside pair of wires.

Make sure one end of the phonecord is plugged into the wall plugicon socket on the modem and theother end into the wall jack of thephone. The phone cord should beno longer than 12 feet in length. Usethe phone cord included with yourmodem, if possible.


PROBLEM DIAGNOSIS POSSIBLE SOLUTIONThe modem will notgo off hook to dial ordoes not answer thephone.

You may have plugged yourmodem’s phone cord into adigital line.

The software you are usingmay not have auto answerenabled.

You may have devicesbetween the modem andthe phone jack.

You may have a poor lineconnection.

If you have voice mail, yourdial tone may be alteredwhen messages arewaiting.

You may be using thewrong power supply foryour external modem

Plugging your modem’s phone cordinto a digital phone line can damagethe modem. Call your phonecompany if you are unsure whetheror not your phone line is digital.

Make sure the auto answer featureis enabled.You need to enable auto answerbefore every session, unless youalter your software’s initializationstring to permanently enable autoanswer.

There should be no line splitters, faxmachines or other devices betweenthe modem and the wall jack.

Try placing the call again. Thephone company routes callsdifferently each time.

Retrieve your voice mail messagesto restore normal dial tone.

Use the power supply that camewith your modem.

Both modemsexchange carriersignals but fail toestablish a link.

You may have a poor lineconnection.

The phone jack may havebeen wired incorrectly.


Contact the telephone company.Ask them to make sure the tip andring are on the outside pair of wires.

User’s Guide 27

PROBLEM DIAGNOSIS POSSIBLE SOLUTIONYour modem will notconnect at 2400bps with a 2400 bpsmodem.

The modem you are tryingto connect with, could be anolder model that does notsupport error control.

You can disable error control onyour modem by typing the followingcommand in the Terminal Mode:AT&M0 and press ENTER. Now tryplacing the call to the remotemodem again. When finished, resetyour modem to enable the errorcontrol features. In Terminal Mode,type ATZ and press ENTER. ATZ4or AT&F1 are often the best resetstrings, as they restore hardwareflow control settings.

Your screen keepsdisplaying randomgarbage characters.

You could have a conflictwith the remote modem’ssettings for word length,parity, and stop bits.

Your software and modemmight not be set to thesame flow control settings.

The best flow controlsettings might not beenabled on your modem.

Your Internet ServiceProvider (ISP) may notprovide x2 service.

The phone connectionmight not be able to handlehigh speed datatransmission.

Set your modem’s word length,parity, and stop bits the same as theremote modem or BBS you arecalling.The common settings are:Data bits - 8Stop bits - 1Parity - none

Make sure the software and modemhave the same flow control ratesettings, either hardware[RTS/CTS] or software [xon/xoff]flow control.

Type this command in TerminalMode to load the optimal hardwareflow control settings, AT&F1 andpress ENTER.

Make sure your ISP offers x2technology or find an ISP who iscapable of providing x2 service.

Try lowering the connection speedyou are using.


PROBLEM DIAGNOSIS POSSIBLE SOLUTIONYourcommunicationssoftware isreporting manycyclic redundancycheck (CRC) errorsand low charactersper second (CPS).

You may have a bad phoneline.

Optimal flow controlsettings may not be enabledon your modem.

The serial port rate in yourcommunications softwaremay be set too high for yourarea’s phone lines or yourmodem’s UART.

The remote site you aredialling into may havetrouble with the file transferprotocol.

There may be a Terminateand Stay Resident (TSR)program (such as a screensaver or virus scanner)running in the background,disrupting datacommunications.

You may be trying todownload a file to acompressed area of yourhard drive.


Type this command in TerminalMode to load the optimal hardwareflow control settings, AT&F1 andpress ENTER.

Lower the serial port rate in yourcommunications software to 57,600bps, 38,400 bps or 19,200 bps. Donot use 14,400, 28,800, or 33,600.The port rate for a ITU-T V.90/x2modem cannot be set lower than57,600, if you want to achieve aITU-T V.90/x2 connection.

Try using a different file transferprotocol. Do not use Xmodem ifother protocols are available.

Disable any Terminate and StayResident (TSR) programs runningin the background. If you havesoftware running as a TSR, checkthe software’s manual forinformation about disabling its abilityto operate as a TSR.

Download to an uncompressed areaon your hard drive.

User’s Guide 29

PROBLEM DIAGNOSIS POSSIBLE SOLUTIONYourcommunicationssoftware isreporting manycyclic redundancycheck (CRC) errorsand low charactersper second (CPS).

Errors areconstantly occurringin your V.17 faxtransmissions.

If your communicationsprogram is DOS-based,you are running it underWindows, at the same timewith other software.Conflicts between theseprograms may be causingthe CRC errors.

Your modem initializationstring could be insufficientfor fax transmissions.

There may be a Terminateand Stay Resident (TSR)program (such as a screensaver or virus scanner)running in the background,disrupting datacommunications.

You could have an outdatedCOM driver on yoursystem.

Your baud rate may be settoo high.

You may be trying to fax acompressed file.

Close every program but thecommunications program.

Type the following initializationstring in Terminal modeAT&H3&I2&R2S7=90S and pressENTER.

Disable any Terminate and StayResident (TSR) programs runningin the background. If you havesoftware running as a TSR, checkthe software’s manual forinformation about disabling its abilityto operate as a TSR.

Load the COM driver that came withyour fax software.

Lower baud rate to 9600, 7200, or4800.

Open the file in the application inwhich it was created. Select yourcommunications software as theprinter and then print the file.

The modemdisplays doublecharacters on yourmonitor.

Both the modem’s andsoftware’s local characterechoes are probably turnedon.

Disable local echo in your softwareOR on your modem (not both). Youcan turn the local echo off on themodem by typing ATE0 andpressing ENTER in your software’sTerminal Mode. To turn the localecho off in the software, refer to itsdocumentation.


PROBLEM DIAGNOSIS POSSIBLE SOLUTIONYour modem cannotachieve a 56KInternet connection.

This modem is capable of56Kbps downloads.However, the downloadspeeds you experience maybe lower due to varying lineconditions and otherfactors. Uploads from usersto server equipment travelat speeds up to 31.2 Kbps.An analogue phone linecompatible with the ITU-TV.90 standard or x2technology, and an Internetprovider or corporate hostsite with the ITU-T 56Kstandard or x2 technologyare necessary for thesehigh-speed downloads.

Call your phone company todetermine if your phone line iscompatible with the ITU-T V.90standard and/or is x2-compatible.

Communicationssoftware fails toinitialize themodem.

The communicationssoftware’s port settings maybe incorrect.

Make sure the communicationssoftware’s port settings are setcorrectly for your modem.

User’s Guide 31

If Plug and Play Does Not Detect Your ModemTry the following:

1. Click Windows 95 Start and click Shut Down. When asked if youwish to shut down your computer, click Yes. When Windows 95indicates that it is safe to turn off your computer, turn it off and wait15 seconds. Then turn the computer back on. Windows 95 maydetect your modem upon this restart even if it did not detect themodem during the initial installation. If you see screens indicatingthat new hardware has been detected by Windows 95, turn to“Installing the Modem Drivers with Windows 95”. If not, continue withthe next step.

2. Click Windows 95 Start, point to Settings, and click Control Panel.Double-click the System icon and then click the Device Managertab on the “System Properties” screen. Look for “Other Devices” or“Unknown Devices” in the list that appears. If you do not see eitherof these options in the list, continue with the next section to learnabout our support options. If you do see one of these options,double-click the option. If the description that appears matches themodem you are trying to install, click Remove. Click OK whenWindows asks if you wish to remove the device. Next, restart thecomputer as described in step 1 on this page. If the computer doesnot detect the modem after this second restart, please refer to oursupport options.


Online Help Resources

Connecting to the 3Com BBS

To connect to the 3Com Bulletin Board System, follow these steps:

1. Start your communications software. The software settings for the BBS are as follows:

ANSI terminal emulation Data Bits: 8 Parity: None Stop Bits: 1

2. Put your computer in Terminal mode. Enter the following command:ATDT 01189692200<Enter>

3. If this is your first time connecting to our BBS, you will be asked to enter your name and a password, as well as fill out a questionnaire.

4. When you finish registering, press enter with each prompt until you come to the main menu. Select the appropriate letter toperform the desired function.

User’s Guide 33

3Com offers a number of other on-line technical support options.Choose any one of the following if you need help with your new Modem.

Internet FTPProvides free library containing the same files as the BBS site. FTP toftp.usr.co.uk

Internet On DemandProvides automatic technical support through a library containingproduct information, quick reference cards and installation help. Toobtain an index of available documents, send blank e-mail [email protected]. To have a document e-mailed to you, send adocument's 3-digit number as the subject.

World Wide WebA 3Com Home Page containing the same information as the Internet onDemand listing as well as information about the U.S. Robotics brandproducts. Logon to http://www.3com.co.uk

Bulletin Board SystemThe 3Com BBS provides answers to the most commonly askedtechnical and non-technical questions.

BBS 0118 9692200

Fax and Technical Support HotlineTechnical questions about U.S. Robotics brand modems can also beanswered via fax or by technical support representatives.

Fax 08708444547Hotline 08708444546


Are You Still Having Problems?

Should you encounter any difficulties with your 56K Message Modemfaxmodem, refer to the manual first.

Call or visit your dealer, if they are unable to assist you, contact the3Com Technical Support Department from Monday through to Friday,during normal office hours on;

Email address: [email protected]: 0118 969 2200Fax: 0870 844 4547Tel: 0870 870 844 4546Web site: http://www.3com.co.uk

Upon contacting 3Com you will be issued with a Call ReferenceNumber (CRN). This should be quoted when contacting the TechnicalSupport Department in relation to your query.

Should you be advised to return your modem, 3Com will repair orreplace and return the unit for you.

Please note that our U.S. Robotics brand modems cannot bereturned without prior approval by the 3Com Technical SupportDepartment.

IMPORTANT : If you are advised to return your unit please shipyour unit packaged securely and make sure that the CRN numberis clearly visible on the outside of the package. Please ship theunit with all charges prepaid and insured.

User’s Guide 35

Section C : Glossary

Cross references are printed in boldface. Cross references withitems in the Command Summary, found in Section D: TechnicalQuick Reference, are printed in italics.

analogue loopbackA modem self-test in which data from the keyboard or an internal testpattern is sent to the modem's transmitter, turned into analogue form,looped back to the receiver, and converted back into digital form.

analogue signalsA variety of signals and wavelengths that can be transmitted overcommunications lines such as the sound of a voice over the phone line.Contrast with digital signals.

answer modeThe mode used by your modem when answering an incoming call froman originating modem. The transmit/receive frequencies are the reverseof the originating modem, which is in originate mode.

applicationA computer program designed to perform a specific function, such as aword processing or organizing data into a spreadsheet.

ARQAutomatic Repeat reQuest. A general term for a function thatautomatically allows your modem to detect flawed data and retransmitit. See MNP and V.42.

ASCIIAmerican Standard Code for Information Interchange. A code used torepresent letters, numbers, and special characters, such as $, !, and /.

asynchronous transmissionData transmission in which the length of time between transmittedcharacters may vary. Because the time lapses between transmittedcharacters are not uniform, the receiving modem must be signaled as


to when the data bits of a character begin and when they end. Theaddition of start/stop bits to each character serves this purpose.

Auto AnswerSets the modem to pick up the phone line when it detects a certainnumber of rings. See S-register S0 in Section D: Technical QuickReference.

auto dialA process where your modem dials a call for you. The dialling processis initiated by sending an ATDT (dial tone) or ATDP (dial pulse)command followed by the telephone number to dial. Auto dial is usedto dial voice numbers. See command Dn.

baud rateA term used to measure the speed of an analogue transmission fromone point to another. Although not technically accurate, baud rate iscommonly used to mean bit rate.

binary digit (bit)A 0 or 1, reflecting the use of the binary numbering system. Usedbecause the computer recognizes either of two states, OFF or ON. Theshortened form of binary digit is bit.

bit rateAlso referred to as transmission rate. The number of binary digits, orbits, transmitted per second (bps). Communications channels usingtelephone channel modems are established at set bit rates, commonly2400, 4800, 9600, 14,400, 28,800 and 33,600.

bits per second (bps)The bits (binary digits) per second rate. Thousands of bits per secondare expressed as kilobits per second or Kbps.

bufferA memory area set aside to be used as temporary storage during inputand output operations. An example is the modem's command buffer.

User’s Guide 37

byteA group of binary digits stored and operated upon as a unit. In userdocumentation, the term usually refers to 8-bit units or characters.One kilobyte (KB) is equal to 1,024 bytes or characters; 640 KBindicates 655,360 bytes or characters.

carrierA tone signifying a connection the modem can alter to communicatedata across telephone lines.

characterA representation, coded in binary digits, of a letter, number, or othersymbol.

characters per second (CPS)A data transfer rate generally estimated from the bit rate and thecharacter length. For example, at 2400 bps, 8-bit characters withstart/stop bits (for a total of ten bits per character) will be transmittedat a rate of approximately 240 characters per second (cps). Someprotocols, such as error-control protocols, employ advancedtechniques such as longer transmission frames and data compressionto increase cps.

class 1 and 2.0International standards used between fax application programs andfaxmodems for sending and receiving faxes.

cyclic redundancy checking (CRC)An error-detection technique consisting of a test performed on eachblock or frame of data by both sending and receiving modems. Thesending modem inserts the results of its tests in each data block in theform of a CRC code. The receiving modem compares its results withthe received CRC code and responds with either a positive or negativeacknowledgment.

data communicationsA type of communications in which computers are able to exchangedata over an electronic medium.


data compression tableA table containing values assigned for each character during a callunder MNP5 data compression. Default values in the table arecontinually altered and built during each call: The longer the table, themore efficient throughput gained.

data modeThe mode in which the faxmodem is capable of sending and receivingdata files. A standard modem without fax capabilities is always in datamode.

DCEData Communications (or Circuit-Terminating) Equipment, such asdial-up modems that establish and control the data link via thetelephone network.

defaultAny setting assumed, at startup or reset, by the computer's softwareand attached devices. The computer or software will use these settingsuntil changed by the user or other software.

detect phaseIn the ITU-T V.42 error-control protocol, the first stage in establishing ifboth modems attempting to connect have V.42 capability.

dictionaryThe term used for compression codes built by the V.42 bis datacompression algorithm.

digital loopbackA test that checks the modem's RS-232 interface and the cable thatconnects the terminal or computer and the modem. The modemreceives data (in the form of digital signals) from the computer orterminal, and immediately returns the data to the screen for verification.

digital signalsDiscrete, uniform signals. In this manual, the term refers to the binarydigits 0 and 1. Contrast with analogue signals.

User’s Guide 39

DTEData Terminal (or Terminating) Equipment. A computer that generatesor is the final destination of data.

duplexIndicates a communications channel capable of carrying signals in bothdirections. See half duplex, full duplex.

Electronic Industries Association (EIA)Group which defines electronic standards in the U.S.

error controlVarious techniques that check the reliability of characters (parity) orblocks of data. V.42 and MNP error-control protocols use errordetection (CRC) and retransmission of flawed frames (ARQ).

facsimileA method for transmitting the image on a page from one point toanother. Commonly referred to as fax.

fax modeThe mode in which the faxmodem is capable of sending and receivingfiles in a facsimile format. See definitions for V.17, V.27ter, V.29.

flow controlA mechanism that compensates for differences in the flow of data intoand out of a modem or other device. See commands &Hn, &In, &Rn.

frameA data communications term for a block of data with header andtrailer information attached. The added information usually includes aframe number, block size data, error-check codes, and Start/Endindicators.

full duplexSignal will flow in both directions at the same time over one line. Inmicrocomputer communications, may refer to the suppression of theonline local echo.


half duplexSignals will flow in both directions, but only one way at a time. Inmicrocomputer communications, may refer to activation of the onlinelocal echo, which causes the modem to send a copy of the transmitteddata to the screen of the sending computer.

HzHertz, a frequency measurement unit used internationally to indicatecycles per second.

ITU-T (International Telecommunications Union)An international organization that defines standards for telegraphic andtelephone equipment. For example, the Bell 212A standard for 1200-bps communication in North America is observed internationally as ITU-T V.22. For 2400-bps communication, most U.S. manufacturersobserve V.22 bis. The initials ITU-T represent the French name. InEnglish it is known as the International Telegraph and TelephoneConsultative Committee.

LAPMLink Access Procedure for Modems. An error-control protocol definedin ITU-T Recommendation V.42. Like the MNP protocols, LAPM usescyclic redundancy checking (CRC) and retransmission of corrupteddata (ARQ) to ensure data reliability.

local echoA modem feature that enables the modem to display keyboardcommands and transmitted data on the screen. See command En.

MNPMicrocom Networking Protocol, an error-control protocol developed byMicrocom, Inc., and now in the public domain. There are severaldifferent MNP protocols, but the most commonly used one ensureserror-free transmission through error detection (CRC) andretransmission of erred frames.

modemA device that transmits/receives computer data through acommunications channel such as radio or telephone lines. It alsochanges signals received from the phone line back to digital signalsbefore passing them to the receiving computer.

User’s Guide 41

nonvolatile memory (NVRAM)User-programmable random access memory whose data is retainedwhen power is turned off. On the Modem, it includes four stored phonenumbers and the modem settings.

off/on hookModem operations that are the equivalent of manually lifting a phonereceiver (taking it off-hook) and replacing it (going on-hook).

online fall back/fall forwardA feature that allows high-speed, error-control modems to monitor linequality and fall back to the next lower speed in a defined range if linequality diminishes. As line conditions improve, the modems switch upto the next higher speed.

originate modeThe mode used by your modem when initiating an outgoing call to adestination modem. The transmit/receive frequencies are the reverse ofthe called modem, which is in answer mode.

originate modeThe mode used by your modem when initiating an outgoing call to adestination modem. The transmit/receive frequencies are the reverse ofthe called modem, which is in answer mode

parityA simple error-detection method that checks the validity of atransmitted character. Character checking has been surpassed bymore reliable and efficient forms of error checking, including V.42 andMNP 2-4 protocols. Either the same type of parity must be used bytwo communicating computers, or both may omit parity.

protocolA system of rules and procedures governing communications betweentwo or more devices. Protocols vary, but communicating devices mustfollow the same protocol in order to exchange data. The format of thedata, readiness to receive or send, error detection and error correctionare some of the operations that may be defined in protocols.


Random Access Memory (RAM) Memory that is available for use when themodem is turned on, but that clears of all information when the power isturned off. The modem's RAM holds the current operational settings, aflow control buffer, and a command buffer.

remote digital loopbackA test that checks the phone link and a remote modem's transmitter andreceiver.

remote echoA copy of the data received by the remote system, returned to thesending system, and displayed on the screen. Remote echoing is afunction of the remote system.

ROMRead Only Memory. Permanent memory, not user-programmable.

serial transmissionThe consecutive flow of data in a single channel. Compare to paralleltransmissions where data flows simultaneously in multiple channels.

start/stop bitsThe signalling bits attached to a character before and after thecharacter is transmitted during asynchronous transmission.

terminalA device whose keyboard and display are used for sending andreceiving data over a communications link. Differs from amicrocomputer or a mainframe in that it has little or no internalprocessing capabilities.

terminal modeSoftware mode that allows direct communication with the modem. Alsoknown as command mode.

User’s Guide 43

throughputThe amount of actual user data transmitted per second without theoverhead of protocol information such as start/stop bits or frameheaders and trailers. Compare with characters per second.

V.8The ITU-T standard specification that covers the initial handshakingprocess.

V.17 faxAn ITU-T standard for making facsimile connections at 14,400 bps,,12,000 bps, 9600 bps, 7200 bps.

V.21An ITU-T standard for modems operating in asynchronous mode atspeeds up to 300 bps, full-duplex, on public switched telephonenetworks.

V.22An ITU-T standard for modem communications at 1200 bps, compatiblewith the Bell 212A standard observed in the U.S. and Canada.

V.22 bisAn ITU-T standard for modem communications at 2400 bps. Thestandard includes an automatic link negotiation fallback to 1200 bpsand compatibility with Bell 212A/V.22 modems.

V.27 terAn ITU-T standard for facsimile operations that specifies modulation at4800 bps, with fallback to 2400 bps.

V.29An ITU-T standard for facsimile operations that specifies modulation at9600 bps, with fallback to 7200 bps.

V.32An ITU-T standard for modem communications at 9600 bps and 4800bps. V.32 modems fall back to 4800 bps when line quality is impaired.


V.32 bisAn ITU-T standard that extends the V.32 connection range: 4800,7200, 9600, 12,000, and 14,400 bps. V.32 bis modems fall back to thenext lower speed when line quality is impaired, fall back further asnecessary, and also fall forward (switch back up) when line conditionsimprove.See online fall back/fall forward.

V.34An ITU-T standard that currently allows data rates as high as 33,600and 28,800 bps.V.42An ITU-T standard for modem communications that defines a two-stageprocess of detection and negotiation for LAPM error control.

V.42 bisAn extension of ITU-T V.42 that defines a specific data compressionscheme for use during V.42 connections.

XmodemThe first of a family of error control software protocols used totransfer files between modems. These protocols are in the publicdomain and are available from many bulletin board services.

XON/XOFFStandard ASCII control characters used to tell an intelligent device tostop/resume transmitting data.

YmodemAn error-checking protocol that can send several files of data at a timein 1024-byte (1K) blocks. This protocol can use either checksums orCRC for error checking.

Ymodem GSimilar to Ymodem, except it includes no error checking, which makesit faster.

ZmodemSimilar to Xmodem and Ymodem, except it includes batch transfer, theability to recover from a partially complete transfer, an autostartfeature, and improved efficiency.

User’s Guide 45

Section D : Technical Quick Reference

Section D includes information about:

• Front Panel Lights (External Modems Only)• Typing Commands• Basic Data Commands• Extended Data Commands• S-Registers• Fax Commands• The Serial Interface (Cable Information)

LED Indicators (Front Panel Lights)

AA Auto Answer Answer mode: ON when register S0 is set to1 or higher (Auto Answer), and whenanswering a call; OFF when modemoriginates a call. Light flashes when there isan incoming call.

MEM Message Memory ON indicates that auto answer is ON and themodem will answer any call when the PC isoff.OFF indicates that auto answer is OFF andthe modem will not answer any call when thePC is off.

CD Carrier Detect ON if modem receives a valid data signal(carrier) from a remote modem, indicatingthat data transmission is possible. AlwaysON if CD override is ON (&C0).

RD Receive Data Flashes when modem sends result codes orpasses received data bits from remotemodem.


SD Send Data Flashes when computer sends a data bit tomodem.

TR Data Terminal Ready ON if modem receives a DTR signalfrom computer. Always ON (modem ignoresDTR) if the DTR override is ON (&D0).

CS Clear to Send ON until modem lowers CTR when transmitdata hardware flow control is enabled(&H1, &H3).

MSG New Message Blinks red once for each new fax message.Blinks green once for each new voicemessage.Solid amber indicates that you haveretrieved your messages, but that they havenot been deleted from memory.

FAX .. Fax Operations ....... Data Mode: Automatic Repeat Request. ONif modem is set to &M4 or &M5 andsuccessfully establishes an error controlconnection. Flashes when modemretransmits data to remote modem.

......... ............................... Fax Mode: Flashes to indicate fax mode.

......... ............................... 56K Message Modem: Dual color LED withgreen indicating 56K Message Modem isenabled and red indicating it is off. Solidgreen indicates no new messages. Eachnew message will be indicated by a singleslow blink. Fast blinking indicates that theflash memory is full.

OH.... Off Hook ................. ON when modem accesses the phone line.OFF when modem is On Hook.

User’s Guide 47

Typing Commands

• Type commands in either upper or lower case, not acombination. Use the Backspace key to deleteerrors. (You cannot delete the original AT commandsince it is stored in the modem buffer.)

• If a command has numeric options and you don’tinclude a number, zero is assumed.For example, if you type ATB, the command ATB0 isassumed.

• Every command except A/,+++ and A> must begin with theAT prefix and be entered by pressing <ENTER>.

• The maximum command length is 58 characters. Thisdoes not include the AT prefix, carriage returns, or spaces.

Note: All defaults are based on the &F1, theHardware Flow Control template loaded in NVRAM whenthe modem is shipped. Defaults are listed in italics.


Basic Data Commands

<control key>S Stop or restart help screens

<control key>C or<control key>K Stop help screens

$ Use in conjunction with D, S, or & commands (or justAT) to display a basic command list; online help.

A Manual Answer: goes off hook in answer mode.Pressing any key aborts the operations.

A/ Re-executes the last issued command. Used mainly toredial. This does not require the AT prefix or a CarriageReturn.

A> Re-executes the last issued command continuously,until the user intervenes or the command is executed.Does not require the AT prefix or a Carriage Return.

Any key Aborts off-hook dial/answer operation and hangs up.

AT Required command prefix, except with A/ and +++, andA. Use alone to test for OK result code.

Bn U.S./ITU-T answer sequence.B0 ITU-T answer sequenceB1 U.S. answer tone

Dn Dials the specified phone number. Includes thefollowing:0-9 Numeric digits#,* Extended touchtone pad tonesL Dials the last dialled number.P Pulse (rotary) dialR Originates call using answer (reverse)

frequencies.Sn Dials the phone number string stored in

NVRAM at position n (n = 0−3). Phonenumbers are stored with the &Zn=s command.

T Tone dial

User’s Guide 49

, (Comma) Pause, See S8 definition; which it’slinked to.

; (Semicolon) Return to Command mode afterdialling.

“ Dials the letters that follow (in an alphabeticalphone number).

! (Exclamation point) Flashes the switch hook./ Delays for 125 ms. before proceeding with dial

string.W Wait for second dial tone (X2 or X4); linked to

S6 register.@ Dials, waits for quiet answer, and continues (X3

or higher).$ Displays a list of Dial commands.

En Sets local echo.E0 Echo OFFE1 Modem displays keyboard commands

Fn Sets online local echo of transmitted data ON/OFF.F0 Local echo ON. Modem sends a copy of data it

sends to the remote system to your screen.F1 Local echo OFF. Receiving system may send a

remote echo of data it receives.

Hn Controls ON/OFF hook.H0 Hangs up (goes on hook).H1 Goes off hook.

In Displays the following information.I0 Four-digit product codeI1 Results of ROM checksumI2 Results of RAM checksumI3 Product typeI4 Current modem settingsI5 Nonvolatile memory (NVRAM) settingsI6 Link diagnosticsI7 Product configurationI9 Plug and Play informationI11 Extended Link Diagnostics

Ln Controls speaker volume (internals only).L0 Lowest


L1 Low volumeL2 Medium volumeL3 High volume

Mn Operates speaker.M0 Speaker always OFF.M1 Speaker ON until CONNECT.M2 Speaker always ON.M3 Speaker ON after dial, until CONNECT.

On Returns online.O0 Returns online.O1 Returns online and retrains.Qn

Qn Displays/suppresses result codes.

Q0 Displays result codes.Q1 Quiet mode; no result codes.Q2 Displays result codes only in Originate mode.

Sr.b=n Sets bit .b of register r to n (0/OFF or 1/ON).

Sr=n Sets register r to n.

Sr? Displays contents of S-Register r.

S$ Displays a list of the S-Registers.

Vn Displays verbal/numeric result codes.V0 Numeric codesV1 Verbal codes

User’s Guide 51

Xn Sets result code displayed. Default is X4.Xn Setting

Result Codes X0 X1 X2 X3 X4

0/OK • • • • •1/CONNECT • • • • •2/RING • • • • •3/NO CARRIER • • • • •4/ERROR • • • • •5/CONNECT 1200 • • • •6/NO DIAL TONE • •7/BUSY • •8/NO ANSWER* • •9/Reserved10/CONNECT 2400 • • • •11/RINGING •13/CONNECT 9600 • • • •18/CONNECT 4800 • • • •20/CONNECT 7200 • • • •21/CONNECT 12000 • • • •25/CONNECT 14400 • • • •43/CONNECT 16800 • • • •85/CONNECT 19200 • • • •91/CONNECT 21600 • • • •99/CONNECT 24000 • • • •103/CONNECT 26400 • • • •107/CONNECT 28800 • • • •151/CONNECT 31200 • • • •155/CONNECT 33600 • • • •


Xn (Continued)

Xn Setting

Result Codes (Continued) X0 X1 X2 X3 X4

256/CONNECT 28000 • • • •260/CONNECT 29333 • • • •264/CONNECT 30666 • • • •268/CONNECT 32000 • • • •180/CONNECT 33333 • • • •272/CONNECT 34666 • • • •276/CONNECT 36000 • • • •184/CONNECT 37333 • • • •280/CONNECT 38666 • • • •284/CONNECT 40000 • • • •188/CONNECT 41333 • • • •192/CONNECT 42666 • • • •196/CONNECT 44000 • • • •200/CONNECT 45333 • • • •204/CONNECT 46666 • • • •208/CONNECT 48000 • • • •212/CONNECT 49333 • • • •216/CONNECT 50666 • • • •220/CONNECT 52000 • • • •224/CONNECT 53333 • • • •228/CONNECT 54666 • • • •232/CONNECT 56000 • • • •236/CONNECT 57333 • • • •

Adaptive Dialling • • •Wait for 2nd Dial Tone (W) • •Wait for Answer (@) • •Fast Dial • •*Requires @ in dial string; replaces NO CARRIER

User’s Guide 53

Extended Data Commands&$ Displays a list of ampersand (&) commands.

&An Enables/disables additional result code subsets.See Xn.&A0 ARQ result codes disabled&A1 ARQ result codes enabled&A2 Modulation indicator added&A3 Protocol indicators addedLAPM/MNP/NONE

(error control) and V42bis/MNP5 (datacompression)

&Bn Manages modem’s serial port rate.&B0 Variable, follows connection rate&B1 Fixed serial port rate&B2 Fixed in ARQ mode, variable in non-ARQ

mode

&Cn Controls Carrier Detect (CD) signal.&C0 CD override&C1 Normal CD operations

&Dn Controls Data Terminal Ready (DTR) operations.&D0 DTR override&D1 DTR toggle causes online Command mode&D2 Normal DTR operations&D3 Resets on receipt of DTR

&Fn Loads a read-only (non-programmable) factoryconfiguration.&F0 Generic template, no flow control&F1 Hardware flow control template&F2 Software flow control template

&Gn Sets Guard Tone.&G0 No guard tone, U.S. and Canada&G1 550 Hz guard tone, some European countries,

requires B0 setting.&G2 1800 Hz guard tone, U.K., requires B0 setting.


&Hn Sets Transmit Data (TD) flow control. See also&Rn.&H0 Flow control disabled&H1 Hardware flow control, Clear to Send (CTS)&H2 Software flow control, XON/XOFF&H3 Hardware and software flow control

&In Sets Receive Data (RD) software flow control. Seealso &Rn.&I0 Software flow control disabled&I1 XON/XOFF signals to your modem and remote

system&I2 XON/XOFF signals to your modem only

&Kn Enables/disables data compression.&K0 Data compression disabled&K1 Auto enable/disable&K2 Data compression enabled&K3 MNP5 compression disabled

&Mn Sets Error Control (ARQ) for connections at 1200bps and higher.&M0 Normal mode, error control disabled&M1 Reserved&M2 Reserved&M3 Reserved&M4 Normal/ARQ&M5 ARQ mode

&Nn Sets connect speed. If connection cannot beestablished at this speed, the modem will hang up.When used in conjunction with &Un and &Un is greaterthan 0, &Nn sets the ceiling connect speed. &Unsets the floor connect speed.. See the table in the&Un section.

&N0 Variable rate&N1 300 bps&N2 1200 bps&N3 2400 bps&N4 4800 bps

&N5 7200 bps&N6 9600 bps&N7 12,000 bps&N8 14,400 bps&N9 16,800 bps

User’s Guide 55

&N10 19,200 bps&N11 21,600 bps&N12 24,000 bps&N13 26,400 bps&N14 28,800 bps&N15 31,200 bps&N16 33,600 bps&N17 28,000 bps&N18 29,333 bps&N19 30,666 bps&N20 32,000 bps&N21 33,333 bps&N22 34,666 bps&N23 36,000 bps&N24 37,333 bps

&N25 38,666 bps&N26 40,000 bps&N27 41,333 bps&N28 42,666 bps&N29 44,000 bps&N30 45,333 bps&N31 46,666 bps&N32 48,000 bps&N33 49,333 bps&N34 50,666 bps&N35 52,000 bps&N36 53,333 bps&N37 54,666 bps&N38 56,000 bps&N39 57,333 bps

&Pn Sets pulse (rotary) dial make/break ratio.&P1 U.K. ratio, 33%/67%

&Rn Sets Receive Data (RD) hardware flow control,Request to Send (RTS). See also &Hn.&R0 Reserved&R1 Modem ignores RTS&R2 Received Data to computer only on RTS

&Sn Controls Data Set Ready (DSR) operations.&S0 DSR override; always ON&S1 Modem controls DSR

&Tn Begins test modes.&T0 Ends testing&T1 Analogue Loopback&T2 Reserved&T3 Local Digital Loopback&T4 Enables Remote Digital Loopback&T5 Prohibits Remote Digital Loopback&T6 Initiates Remote Digital Loopback&T7 Remote Digital with self-test and error detector&T8 Analogue Loopback with self-test and error

detector


&Un Sets floor connect speed when &Un is set above 0.If the connection cannot be established above thisspeed, the modem will hang up. When &Un is usedin conjunction with &Nn and &Nn is greater than 0,&Nn is the ceiling connect speed..

&N=0 &N>0&U=0 Connects at best Connects at speed

possible speed defined by &Nn. Ifconnection cannot be established at this speed, themodem will hang up.with the remote modem.

Note: The factory default settings of &N and &U should besufficient for most users.

&U>0 Connects at fastest speed possible above the value of&Un. Connects at fastest speed possible between&Nn. and &Un

&U0 No restrictions on the minimum speed of the connection&U1 300 bps&U2 1200 bps&U3 2400 bps&U4 4800 bps&U5 7200 bps&U6 9600 bps&U7 12,000 bps&U8 14,400 bps&U9 16,800 bps&U10 19,200 bps&U11 21,600 bps&U12 24,000 bps&U13 26,400 bps&U14 28,800 bps&U15 31,200 bps&U16 33,600 bps&U17 28000 bps&U18 29333 bps&U19 30666 bps&U20 32000 bps

&U21 33,333 bps&U22 34666 bps&U23 36000 bps&U24 37,333 bps&U25 38666 bps&U26 40000 bps&U27 41,333 bps&U28 42,666 bps&U29 44,000 bps&U30 45,333 bps&U31 46666 bps&U32 48000 bps&U33 49333 bps&U34 50666 bps&U35 52000 bps&U36 53333 bps&U37 54666 bps&U38 56000 bps&U39 57333 bps

User’s Guide 57

&Wn Writes current configuration to NVRAM templates.&W0 Modifies the NVRAM 0 template (Y0)&W1 Modifies the NVRAM 1 template (Y1)

&Yn Sets break handling.&Y0 Destructive, but doesn’t send break&Y1 Destructive, expedited&Y2 Nondestructive, expedited&Y3 Nondestructive, unexpedited

&Zn=s Writes phone number string s NVRAM at position n (n= 0−3).

&Zn=L Writes last executed dial string to NVRAM at position n(n = 0−3).

&Zn? Displays the phone number stored at position n (n = 0−3).

&ZL? Displays the last executed dial string.

+++ Escapes to online-command mode.

+++ Escapes to online-command mode.


S-Registers

To change a setting, use the ATSr=n command, where r isthe register and n is a decimal value from 0 − 255 (unlessotherwise indicated).

Register Default FunctionS0 0 Sets the number of rings on which to answer in Auto

Answer Mode. When set to 0, Auto Answer isdisabled.

S1 0 Counts and stores the number of rings from anincoming call. (S0 must be greater than 0.)

S2 43 Stores the ASCII decimal code for the escape codecharacter. Default character is +. A value of 128 –255 disables the escape code.

S3 13 Stores the ASCII code for the Carriage Returncharacter. Valid range is 0 – 127.

S4 10 Stores the ASCII decimal code for the Line Feedcharacter. Valid range is 0 – 127.

S5 8 Stores the ASCII decimal code for the Backspacecharacter. A value of 128−255 disables theBackspace key’s delete function.

S6 2 Sets the number of seconds the modem waitsbefore dialling. If Xn is set to X2 or X4, this is thetime-out length if there isn't a dial tone.

S7 60 Sets the number of seconds the modem waits for acarrier. May be set for much longer duration if, forexample, the modem is originating an internationalconnection.

User’s Guide 59

Register Default Function

S8 2 Sets the duration, in seconds, for the pause (,) optionin the Dial command.

S9 6 Sets the required duration, in tenths of a second, ofthe remote modem’s carrier signal before recognitionby the modem.

S10 7 Sets the duration, in tenths of a second, that themodem waits to hang up after loss of carrier. Thisguard time allows the modem to distinguish betweena line disturbance from a true disconnect (hang up)by the remote modem.

.

NOTE: If you set S10 = 255, the modem will nothang up when carrier is lost. Dropping DTR hangsup the modem.

S11 70 Sets the duration and spacing, in milliseconds, fortone dialling.

S12 50 Sets the duration, in fiftieths of a second, of theguard time for the escape code sequence (+++).



S13 0 Bit-mapped register. Select the bit(s) you want on and setS13 to the total of the values in theValue column. Forexample, ATS13 = 17 enables bit 0 (value is 1) and bit 4(value is 16).

Bit Value Result0 1 Reset when DTR drops.1 2 Reset non-MNP transmit buffer from

1.5K to 128 bytes.*2 4 Set backspace key to delete.3 8 On DTR signal, auto dial the number

stored in NVRAM at position 0.4 16 At power on/reset, Auto Dial the

number stored in NVRAM atposition 0.

5 32 Reserved6 64 Disable quick retrains.7 128 Disconnect on escape code.

* The 1.5K-byte non-ARQ buffer allows data transfer withXmodem- and Ymodem-type file transfer protocols withoutusing flow control.

The 128-byte option lets remote users with slower modems keepdata you’re sending from scrolling off their screens. Whenremote users send your computer an XOFF (Ctrl-S) and youstop transmitting, the data in transit from your modem’s bufferdoesn’t exceed the size of their screen. This is also very helpfulin situations when a remote modem/printer application is losingcharacters.

User’s Guide 61


S14 0 Reserved

S15 0 Bit-mapped register setup. To set the register, seeinstructions for S13.

Bit Value Result0 1 Disable ARQ/MNP for V.22.1 2 Disable ARQ/MNP for V.22bis.2 4 Disable ARQ/MNP

V.32/V.32bis/V.32terbo.3 8 Disable MNP handshake.4 16 Disable MNP level 4.5 32 Disable MNP level 3.6 64 MNP incompatibility.7 128 Disable V.42 operation.To disable V.42 detect phase, select the total of thevalues for bits 3 and 7 (in other words S15+136 [thesum of values 8 and 128])

S16 0 Reserved

S17 0 Reserved

S18 0 Test timer for &T loopback testing. Sets the time inseconds of testing before the modem automaticallytimes out and terminates the test. When set to 0, thetimer is disabled. Valid range is 1-255.

S19 0 Sets the duration, in minutes, for the inactivity timer.The timer activates when there is no data activity onthe phone line; at time-out the modem hangs up.S19 = 0 disables the timer.

S20 0 Reserved



S21 10 Sets the length, in 10-millisecond units, of breakssent from the modem to the computer; applies toMNP or V.42 mode only.

S22 17 Stores the ASCII decimal code for the XONcharacter.

S23 19 Stores the ASCII decimal code for the XOFFcharacter.

S24 0 Reserved

S25 20 Sets the duration, in hundredths of a second, thatDTR must be dropped so that the modem doesn’tinterpret a random glitch as a DTR loss. (Most userswill want to use the default; this register is useful forsetting compatibility with older systems runningunder older operating software.)

S26 0 Reserved

S27 0 Bit-mapped register setup. To set the register, seeinstructions for S13.

Bit Value Result0 1 Enables ITU-T V.21 modulation at

300 bps. 1 2Enables unencoded

(non-trellis coded) modulation inV.32 mode.

2 4 Disables V.32 modulation.3 8 Disables 2100 Hz answer tone to

allow two V.42 modems toconnect faster.

4 16 Enables V.23 modulation.5 32 Disables V.32bis mode.6 64 Disable V.42 selective reject.

User’s Guide 63


7 128 Software compatibility mode. Thissetting disables the codes anddisplays the 9600 code instead.The actual rate of the call can beviewed on the ATI6 screen Usedfor unusual softwareincompatibilities. Some softwaremay not accept 7200, 12,000, and14,400 bps or greater result codes.

S28 0 Eliminates the V.32 answer tones for a fasterconnection.

8 Default item, all times are in tenths of seconds.

255 Disables all connections except V.32 at 9600 bps.

S29 20 Sets the duration, in tenths of a second, of the V.21answer mode fallback timer.

S30 0 Reserved

S31 128 Reserved

S32 2 Bit mapped register setup. To set the register, seethe instructions for S13.

Bit Value Result0 1 V.8 Call Indicate enabled.1 2 Enables V.8 mode.2 4 Reserved.3 8 Disable V.34 modulation.4 16 Disable V.34+ modulation.5 32 Disable x2 modulation.6 64 Disable V.90 modulation.7 128 Reserved.



S33 0 Bit mapped register setup. To set theregister, see the instructionsfor S13.

Bit Value Result0 1 Disable 2400 symbol rate.1 2 Disable 2743 symbol rate.2 4 Disable 2800 symbol rate.3 8 Disable 3000 symbol rate.4 16 Disable 3200 symbol rate.5 32 Disable 3429 symbol rate.6 64 Reserved7 128 Disable shaping.

S34 0 Bit mapped register setup. To set registers, seeinstructions for S13.

Bit Value Result

0 1 Disable 8S-2D trellis encoding.1 2 Disable 16S-4D trellis encoding.2 4 Disable 32S-2D trellis encoding.3 8 Disable 64S-4D trellis encoding.4 16 Disable non-linear coding.5 32 Disable TX level deviation.6 64 Disable Pre-emphasis.7 128 Disable Pre-coding.

S35-S37 Reserved

User’s Guide 65


S38 0 Sets an optional delay, in seconds, before a forcedhang-up and clearing of the Transmit buffer when DTRdrops during an ARQ call. This allows time for aremote modem to acknowledge receipt of alltransmitted data before it is disconnected. Themodem immediately hangs up when DTR drops.

This option only applies to connections terminated bydropping DTR. If the modem receives the ATHcommand, it ignores S38 and immediately hangs up.

S39-S40 0 Reserved

S41 0 Reserved

S42 0 Reserved

S43 112 Autonomous 8-bit S-Register. Bit mapped registerstored in NVRAM.

Bit Value Result

0 1 56K Message Modemdisabled.

1 2 Dialup Retrieval disabled.

2 4 N/A

3 8 Monitor disable.

4 16 Fax Reception and Storageenabled.

5 32 Voice Reception and Storageenabled.

6 64 (High) Answer in SR Modeafter four RINGs.

7 128 (Low) Answer in SR Modeafter four RINGs.


Fax Commands

FCLASS=n Sets the mode of operationFCLASS=0 Data modeFCLASS=1 Group 3 Facsimile Service Class 1

modeFCLASS=2.0 Group 3 Facsimile Service Class 2.0

mode

FCLASS? Displays the current FCLASS mode (See mode descriptions above)

+FCLASS=? Displays the FCLASS mode options(See mode descriptions above)

+FTS=n Stops the fax transmission. Then the modem waits for a specified time before OK appears on screen. The pause is set in 10 millisecond intervals. n is the number of 10 millisecond intervals that pass before OK appears. (n=0-255)

+FRS=n Makes the modem wait for a specified length of silence before sending OK to the screen. The pause is set in10 millisecond intervals. n is the number of 10 millisecondintervals that pass before OKappears.(n=0-255) Note: This command terminates with OK when either the specified amount of silence is detected or when the user types anything (which is ignored).

+FTM=n Transmits data using the modulation specified by n.(n = 3, 24, 48, 72, 96, 97, 98, 121, 122, 145, or 146)Note: See the “Screen Messages” table at the end of this section for an explanation of messages that appear in response to this command.

+FRM=n Receives data using the modulation specified by n.(n = 3, 24, 48, 72, 96, 97, 98, 121, 122, 145,or 146) Note: See the “Screen Messages”table at the end of this section for an explanation ofmessages that appear in response to this command.

User’s Guide 67

+FTH=n Transmits data framed in the HDLC protocol using the modulation specified by n. (n = 3, 24, 48, 72, 96, 97, 98, 121,122, 145, or 146)Note: See the “Screen Messages” table at the end of this section for an explanation of messages that appear in response to this command.

+FRH=n Receives data framed in the HDLC protocol using the modulation specified by n. (n = 3, 24, 48, 72, 96, 97, 98, 121, 122, 145, or 146)Note: See the “Screen Messages” table at the end of this section for an explanation of messages that appear in response to this command.

Screen Messages

Displayed Displayed Descriptionas a number in words

0 OK The previous command has been processed successfully.

1 CONNECT The modem has just connected to another modem.

2 RING Reports the receipt of a network altering ring.

3 NO CARRIER No carrier is being received fromthe modem.

4 ERROR The previous command line has notbeen recognized or was completedabnormally.

5 NO DIAL (Optional) Dial tone was not received TONE within the time-out period.

6 BUSY (Optional) A busy signal was deleted.

64 CONNECT/FAX (Optional) The modem has established a fax connection. This response is usedonly when the fax mode is selected.


The Serial Interface

The serial interface is a standard developed by the Electronic IndustriesAssociation (EIA). It defines the signals and voltages used when datais exchanged between a computer and a modem or serial printer.

The entire standard covers many more functions than are used in mostdata communications applications. Data is transmitted between thedevices over a shielded serial cable with a 25-pin male (DB-25P)connector to the modem and a 25-pin, 9-pin, 8-pin, or custom-builtconnector to the computer.

Pin assignments are factory-set in the 56K Message Modem to matchthe standard DB-25 assignments in the following table. DB-9connectors for IBM/AT-compatible computers should be wired at thecomputer end of the cable as shown in the DB-9 column.

Serial Interface Pin Definitions

Signal SourceDB-25DB-9 Circuit Function Computer/Modem

1 — AA Chassis Ground Both2 3 BA Transmitted Data Computer3 2 BB Received Data Modem4 7 CA Request to Send Computer5 8 CB Clear to Send Modem6 6 CC Data Set Ready Modem7 5 AB Signal Ground Both8 1 CF Carrier Detect Modem12 — SCF Speed Indicate Modem20 4 CD Data Terminal Ready Computer22 9 CE Ring Indicate Modem

User’s Guide 69

Section E : CE Compliance

Electromagnetic CompatibilityThis device complies with the following standards in accordance withEuropean Directives 89/336/EEC:

• Immunity EN 50082-1 06/92

• Emission EN 55022 class B 08/87

Safety (Low Voltage Directive)This device complies with the following standards in accordance withEuropean Directive 91/263/EEC and 91/263/EEC:

• EN 60950/A2 10/93

• EN 41003 08/93

The ports on this modem have the following safety status:

• Telephone line connector = TNV

• All other ports = SELV

These definitions are classified as per safety standard:

EN 60950/A2 10/93.

• SELV: Safety Extra Low Voltage

• TNV: Telecommunications Network Voltage, voltagesin compliance with standard EN 41003 08/93 criteria.


CTR 21 Approval (in the UK and Ireland only)

This equipment has been approved in accordance with CouncilDecision 98/482/EC for pan-European single terminalconnection to the Public Switched Telephone Network (PSTN).However, due to differences between the individual PSTNsprovided in different countries, the approval does not, of itself,give an unconditional assurance of successful operation onevery PSTN network termination point.

In the event of problems, you should contact your equipmentsupplier in the first instance.

Network Compatibility Declaration

This equipment is designed to work satisfactorily on allEuropean Union PSTN networks.

This equipment is supplied with a suitable PSTN connector forthe country in which it was supplied. If it is required to use thisequipment on a different network to the one for which it wassupplied, the user is advised to contact the vendor for guidanceregarding connection.

User’s Guide 71

Section F : Limited Warranty

3Com UK Limited warrants to the original consumer or other end userthat this product is free from defects in materials or workmanship forthe lifetime of the product. Upon proof of purchase, the product will berepaired or replaced (with the same or similar model) at our option,without charge for either parts or labour. This warranty shall not apply ifthe product is modified, tampered with, misused or subjected toabnormal working conditions.

REPAIR AND REPLACEMENT AS PROVIDED UNDER THIS WARRANTY IS THEEXCLUSIVE REMEDY OF THE PURCHASER. THIS WARRANTY IS IN LIEU OF ALLOTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING ANY IMPLIEDWARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE ORPURPOSE AND 3COM U.S. ROBOTICS SHALL IN NO EVENT BE LIABLE TO THEPURCHASER FOR THE INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND ORCHARACTER.

If you would like further information or the name of your nearest 3Com

dealer, call SALES on,

FREEPHONE 0 8 0 0 2 2 5 2 5 2

or look at,

http://www.3com.co.uk

NOTE - For Technical Support, refer to the Contact3Com Technical Support section.

All U.S. Robotics brand modems are BABT approved and CE marked,and are supplied with free lifetime technical support.

3Com U.S. Robotics

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