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INPLANT TRAINING REPORT
ITI Bhavan Doorvaninagar
Bangalore : 560016Karnataka ,India .
SUBMITTED TO : SUBMITTED BY:
Mr.Ronny S Estibeiro Arpita Saha( ID no-4222)
Asst Officer-HR-ED B.Tech (ECE) 7THSemester
ITI Limited, Dooravaninagar Institute of Technology
Bangalore-560016 Guru Ghasidas Vishwavidyalaya
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Acknowledgement
I am highly indebted to Indian Telephone Industries
Limited team for their guidance and constant
supervision as well as for providing necessary
information regarding the project on transformers &
also for their support in completing the project and
learning outcome.
My special thanks and regards also goes to my
supervisors and engineers in developing the project
and people who have willingly helped me out and
motivated me with their abilities throughout.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
prefaceAt very outset of the prologue it becomes imperative to insistthat vocational training is an integral part of engineering
curriculum. Training allows us to gain an insight into thepractical aspects of the various topics, with which we come
across while pursuing our B.Tech i.e. vocational training givesus practical implementation of various topics we already have
learned and will learn in near future.Vocational trainingalways emphasizes on logic and common sense instead oftheoretical aspects of subject.On my part, I pursued four weekstraining at I.T.I Limited, Bangalore. The training involved a
study of various departments of the organization as per the timelogically scheduled and well planned given to us.
Arpita SahaId no -4222
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
cmpany Profile
COMPANY PROFILE:
Indias first Public Sector Unit (PSU) - ITI Ltd was established in 1948.Ever since, as a pioneering venture in the field of telecommunications,
it has contributed to 50% of the present national telecom network.
With state-of-the-art manufacturing facilities spread across six
locations and a countrywide network of marketing/service outlets, the
company offers a complete range of telecom products and total
solutions covering the whole spectrum of Switching, Transmission,
Access and Subscriber Premises equipment.
ITI joined the league of world class vendors of Global System for
Mobile (GSM) technology with the inauguration of mobile equipment
manufacturing facilities at its Mankapur and Rae Bareli Plants in 2005-
06. This ushered in a new era of indigenous mobile equipment
production in the country. These two facilities supply more than nine
million lines per annum to both domestic as well as export markets.
The company is consolidating its diversification into Information and
Communication Technology (ICT) to hone its competitive edge in the
convergence market by deploying its rich telecom expertise and vast
infrastructure. Network Management Systems, Encryption and
Networking Solutions for Internet Connectivity are some of the major
initiatives taken by the company.
Secure communications is the company's forte with a proven record of
engineering strategic communication networks for India's Defence
forces. Extensive in-house R&D work is devoted towards specialized
areas of Encryption, NMS, IT and Access products to provide complete
customized solutions to various customers.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Unit Profile
UNIT PROFILE
Bangalore Unit is the first Plant of ITI set up in 1948. With its,
vertically integrated, state-of-the-art infrastructure a vast range of
telecom products are manufactured. They include digital switches
(large, medium, small), Digital Microwave equipment, optic fibre
equipments, satellite communication equipment, access products,terminal equipments.
Areas of business
Telecom Equipment Manufacture for Defence and Civilians
applications
Installation & Communication
Turnkey Solutions
IT Networks
Diversified Products
Products
Switching: CSN-MM,C-DOT,ISDN and PABX
Access: WLL/CDMA INFRA, Broadband CorDECT(EDWAS),Antenna
GSM/CDMA
Transmission: IDR SATCOM Microwave
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Terminal Equipments:Caller ID Phones
Defence Equipments: ORDERWIRE SECRECY(OWS) , ANADA MK II
BEU, MIL PCM SECRECY , L VSAT 5B/5C TELEPHONES, PRIMARY
MUX
ASCON
EPBT
ADSL-CPEs, Secrecy Equipments
INFO KIOSKS and Desktop Computers
Facilities
SMT Line
Consists of Screen Printer,Glue
Dispenser,Chip Shooter,Fine Placer andReflow Oven
Capability : 40000 components / hr.
Chip shooter : Placement minimum size
0603 (1.5mm x 0.75mm) components to
max. size 55mm x 55 mm ICs. Fine
placement upto 0.5mm Pitch & Accuracy of
25 microns
Capacity : 150 million components per
annum
Mechanical Fabricaton and Assembly
Machines available:
CNC Turret Punch Press (30 tons), NC
Pressbrakes (upto 120 tons), CNC Shearing
(2.5 mtrs) and General purpose machines
Capability: Handling sheet metal work of
2mm thickness of stainless steel, 2.5mm MS
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
& 3.2mm Aluminium
Capacity: Process about 100 tons of Sheet
Metal per month
Plastic Injection TechnologyCapability: 25 to 300 tons
Capacity: 0.5 million shots per annum
Through-Hole Component Assembly
Capability :Dual wave and Nitrogen
atmosphere wave solderingCapacity : 36 million components per annum
PCB Manufacturing
Capability :Single Layer to 4 Layer
Capacity : 3000 Sq.Metres per annum
Wave Soldering machine
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Testing Facilities
In-Circuit Testers (upto 2000 nodes)
Capability :Detects open, short, continuity,
correctness of the components with respectto Orientation, Value, etc
Capacity : 1,50,000 cards per year (average)
Functional testing for cards
System Testing
Tool Room
Capability:Manufacture and maintenance of
moulding tools, press tools, jigs & fixtures
Capacity:Supporting in-house requirements
Finishing
Capability: Electroplating and Powder coating facilities
Capacity: Supporting in-house fabrication
Nickel plating
Non-cyanide plating
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Upgraded Zinc Phosphating plant
Other Support Facilities
EMI Shielded Chamber
Electrical Test Lab.
Mechanical Test Lab.
Chemical Test Lab
Environmental Testing FacilityTotal Turnkey Solutions
CDMA Network : 4.4 Million Lines - Supply, Installation and
Commissioning for BSNL
Army Static Communication Network (ASCON) for Defence Forces
(Covering entire country)
CIVICON PROJECT for Ministry of Home Affairs (Turn-key Network
Implementation)
CARNATION Project for Indian ARMY (Wide Area Strategic Network)IDR Project for BSNL
MCPC VSAT for BSNL
Point to Point Satellite based Links for RCPO
LICO VSAT for Indian ARMY
SCPC DAMA Equipment
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Table of Contentscompany Profile .................................................................................................................................. 4
TELEPHONE AND DEFENCE PRODUCTSTELEPHONE MAGNETO ........................................................... 12
TELEPHONE MAGNETO ......................................................................................................................... 13
THE AUTOMATIC TELEPHONE ........................................................................................................... 14
DTMF (Dual Tone Multi Frequency) .................................................................................................. 17
PCB MANUFACTURING ..................................................................................................................... 19
RESEARCH AND DEVELOPMENT ........................................................................................................... 25
SCADA ............................................................................................................................................... 26
POWER SUPPLY UNIT ........................................................................................................................ 31
Linear power supplies: .................................................................................................................. 31
Switched Mode Power Supply ...................................................................................................... 32
WIRELESS LAB ................................................................................................................................... 34
MODEM................................................................................................................................. 34
WIRELESS ISM TRANSMITTER ............................................................................................... 34
CAD(Computer Aided Design) ........................................................................................................... 35
PCB Basics ..................................................................................................................................... 35
Device Mounting ........................................................................................................................... 35
Traces ............................................................................................................................................ 36
Decoupling Capacitors .................................................................................................................. 37
Measurements .............................................................................................................................. 37
INFORMATION TECHNOLOGY ............................................................................................................... 38
IVRS( Interactive Voice Response System Software) ........................................................................ 39
SWITCHING AND ACCESS PRODUCTS ................................................................................................... 44
SMT (Surface mount technology) ..................................................................................................... 45
What are SMT components? ............................................................................................................ 45
STENCIL PRINTER GLUE DISPENSER CHIP SHOOTER ...................... 48
REFLOW OVEN OPTICAL INSEPCTION FINE PLACER........ 48
BTS (Base Trans-Receiver Station) .................................................................................................... 49
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
CDMA (Code Division Multiple Access) ............................................................................................. 51
OCB (Organ do Commando B) Telephone Exchange ........................................................................ 53
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
TELEPHONE AND DEFENCE
PRODUCTS
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
TELEPHONE MAGNETOA magneto is anelectrical generatorthat usespermanent magnetsto produce
alternating current. Owing to their simplicity and reliability, they were widely used
in earlytelephonesystems.
Many early manualtelephoneshad a hand cranked "magneto" generator to produce
a (relatively) high voltage alternating signal to ring the bells of other telephones on
the same (party) line and to alert the operator. These were usually on long rural lines
served by small manual exchanges, which were not "common battery". The
telephone instrument was "local battery", containing two large "No. 6"zinc-
carbondry cells. By around 1900, large racks ofmotor-generator setsin the
telephone exchange supplied this ringing current instead and the local magneto wasno longer required.
A gear mechanism was used to speed-up the crank rotation to the speed of the
magneto armature. Telephone magnetos also incorporate a switch that only engages
when rotating, so that the magneto is normally out of circuit.
The last survival of ringing current magnetos in the public telephone network (PSTN)
was as late as the 1980s, where they were still used with PMBX (Private Manual
Branch Exchange, a small business switchboard, worked by operators). Rather than
providing a motor generator set for such a small installation, along with its noise and
need for mechanical maintenance, a hand magneto was used. Unlike the public
telephone network and its standard ringing cadence (two pulses, then a gap, in the
UK) the cadence of a manual ringer depended on the operator. When ringing local
extensions, some switchboard operators used local codes of ringing to indicate
internal, external or urgent calls.
Around the same time, the linesman's test set still included a magneto, for use whenringing out to either the exchange or the subscriber, from anywhere along the line.
These lasted into the 1980s.
http://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Electrical_generatorhttp://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Motor-generator_sethttp://en.wikipedia.org/wiki/Motor-generator_sethttp://en.wikipedia.org/wiki/Motor-generator_sethttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/PSTNhttp://en.wikipedia.org/wiki/Motor-generator_sethttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Zinc-carbon_batteryhttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Telephonehttp://en.wikipedia.org/wiki/Magnethttp://en.wikipedia.org/wiki/Electrical_generator -
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
THE AUTOMATIC TELEPHONEThe term automatic telephone means a telephone system fitted with automatic
electric devices such that the user, by means of a numerical dial attached to the
instrument can:
i) Establish a connection in a large public exchange, in from three to
five seconds
ii) Be sure that he gets the number he dialled
iii) Receive a positive signal, if the line be busy
iv) Break the connections when he desires
The transmitter, receiver, ringer, and hook switch for an automatic telephone may be
of any standard type. The only part of the instrument that is peculiar to the automatic
system is the calling device or dial. At the central office, the machines which make
the connections between subscribers lines are divided into the following classes:
1. Line switches
2. Selector switches
3. Connector switches
According to the size of the installations the automatic telephone system may be
classed as:
Single office exchange;
Multi-office exchange;
Private automatic exchange (PAX).
SUBSCRIBERS DIAL-
The function of this device is to alter the electrical condition of line in such a way as
to cause the apparatus at the central office to complete the desired connection. It
consists of a dial pivoted at the centre and arranged so that it may be turned in a
clockwise direction.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
SUBSCRIBERS CIRCUIT
When the subscriber dials a number, the circuit will be opened a number of times
corresponding to the number called and this is the principle upon which the
apparatus at the central station depends to make the connection.
When the dial is moved from the initial position, the shunt springs close contact,
maintaining a shunt around the transmitter and receiver until such time as the dial
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
returns to its initial position. This prevents variation of resistance in the subscribers
loop and irregular operation of the central office mechanism.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
DTMF (Dual Tone Multi Frequency)
The abbreviation DTMF stands for Dual Tone Multi Frequency, and is a method ofrepresenting digits with tone frequencies, in order to transmit them over an analogcommunications network, for example a telephone line. During development, carewas taken to make use of all frequencies in the voice band, in order to reduce thedemands placed on the transmission channel. In telephone networks, DTMF signalsare used to encode dial trains and other information. Although the method used untilnow to form dial trains from a sequence of current pulses is still the standard inGermany, the transmission time is too long and places an unnecessary loading onthe network. In addition, many telecommunications services are only available withthe use of tone dialing.
For DTMF encoding, the digits 0-9 and the characters A-D, */E and #/F arerepresented as acombination of two frequencies:
Frequency 1209 Hz 1336 Hz 1477 Hz 1633 Hz
697 Hz 1 2 3 A
770 Hz 4 5 6 B
852 Hz 7 8 9 C
941 Hz */E 0 #/F D
With this system, the column is represented by a frequency from the upperfrequency group (Hi-Group: 1209-1633 Hz), and the line by a frequency from thelower frequency group (Lo- Group: 697-941 Hz). The tone frequencies have beenchosen such that harmonics are avoided. No frequency is the multiple of another,and in no case does the sum or difference of two frequencies result in another DTMFfrequency.
For the generation of a dial train in Telecom network some specifications must bemet : The deviation of the actual frequencies generated from the nominal frequency mustbe amaximum of 1.8% during the dialling process The envelope of the dial train must conform to the waveform shown in Figure 1:
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
The voltage levels must conform to the following values:
DialingCharacter
Time
Time BetweenCharacters
Minimum level indB (950mV)
fu fo
Maximum levelin dB (950mV)
fu fo
Automatic dialing, or
manualdialing with automatic
time
limiting
65mst100ms 80mst6500ms -16 -14 -10.5 -8.5
Manual dialing withouttimelimiting
t65ms t80ms -16 -14 -13 -11
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
PCB MANUFACTURINGPURPOSE
To systematically plan and control all processes to manufacture quality PCBs which
shall meet all specified quality, delivery and cost requirements.
PROCEDURE
1.MECHANICAL
CNC drilling and routing are validated on a weekly basis by the dispersion tests and
the results are represented graphically and displayed on the machine. Any special
instruction will be sent to maintenance which help them to know this status ofmachine and to carry out the necessary preventive maintenance if required. The
work is carried out as called for in work instruction PCB/MEC/WI.
1.1.DRILLING
It is responsible for drawing the laminates. Cutting these sheets to the required
blanks as per the cutting order and fabrication order, curing the cut blanks in the
oven, stack pinning the blanks with backup sheets at the bottom and entry sheet at
the top, loading the stacked blanks on the drilling machine with the drill tape given by
the methods, reading in and performing the drilling operations. Drilled blanks are
checked with drill check diazo ( a diazo film with all holes drilled) given by methods.
The blanks are depinned and deburred for removing the burrs formed during drilling
operation and sent to electronic plating line centre. Non-plated through holes (Non-
PTH) Boards are sent to pumicing centre directly by passing electronless plating line.
1.2 ROUTING
The boards after Hot air leveling and legend printing if required reach routing section
for contouring to its specified shape and size. The work is carried out on CNC
Machine with routing programme supplied by methods. Routed boards are checked
thoroughly for dimensional aspects and plated through holes to edge and non plated
through holes to edge details, to the satisfaction of the routing control drawing
furnished by methods. The boards which require bevelling as per F.O. will be
chamfered in the bevelling machine and all the PCBs are then sent to final Quality
Control inspection area after cleaning.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
2. IMAGE TRANSFER
The quality of the PCB is highly dependable on the quality of the circuits transferred
on the blank. The correct circuit image transfer requires correct exposure
techniques. The correct exposure and there by proper image transfer is controlled by
step tablet technique. The work instructions for this area is covered under
PCB/TT/WI.
2.1 PHOTO IMAGE TRANSFER
Photo image transfer section carries out the following processes by which the image
of the circuit to the code is embedded to the blank.
1) Pumicing
Process of preparing the surface of the blank to hold dry film firmly on the blank
during the lamination of the dry film. The processes involves the scrubbing of
surface of blank by pumicing brushes with pumice powder in slurry to provide the
blank surface a little roughness.
2) Lamination
The technique involves the processes of covering both sides of the blank with
photo sensitive dry film mounted on the hot roll laminate.
3) Registration
The process of aligning the respective film (diazo) on the blank correctly and
exposing under UV light using the exposure machine. This process transfers the
image of the circuit on the blank.
4) Development
The exposed blanks are fed to the developer units where the same are
developed in potassium/sodium carbonate where aqueous base film is used.
5) Development verification
The development blanks are thoroughly checked for defects and good boards are
sent for Quality control. The defective boards are sent for reprocessing. The
boards passed by Q.C are sent with the F.O to plating duly certified. The blanks
with minor defects are repaired by the PIT Production personal and blanks having
major problem are segregated and sent for rework with duplicates F.O number of
the original.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
2.2 SCREEN PRINTING
In Screen Printing area there are two types of operations. Soldermasking and
Legend printing Photo imageable solder mask is used.
1) Soldermasking
It is during this process PCBs are scrubbed and given a coating of soldermask.
The soldermask protects the areas of PCBs other than component insertion
points which gets soldered during wave soldering. Next the respective film is
aligned on the board, and the boards are exposed , developed and inspected.
2) Legend printing
Legend printing is the operation carried out for selected PCBs, as indicated in F.O,
which give the marking of various components coming over the particular PCBs for
easy identification I the assembly stage of the PCB.
The boards after screen printing/ PISM are cured and sent for Hot Air Levelling.
3 .PLATING
Electronics and Electroplating deposition are controlled and monitored by Chemical
Laboratory. They perform various analysis like hull cell test, and regularly use glass
exposure plate to find the quality and quantity of the deposition. The work instruction
for this area is covered under PCB/PT/WI.
ELECTRONLESS PLATING LINE OF THE PLATING AND TREATMENT SECTION
This area perform the activity of providing and overall coating of copper all over the
blank including inside the holes by chemical processes. Electronless plated blanks
are sent for Photo image Transfer operation.
PLATING AND TREATMENT AREA
The blanks received from the PIT section are subjected to deposition of copper
followed by tin lead Electrolytically. After electro-plating boards are taken to the
treatment processes. The treatment involves the following operation:
1) Stripping:
The dry film which acted as plating resist during electrolyte plating of Tin lead
is removed in the process.
2) Etching:
Copper is removed from the where it is not required by etching.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
TIN-LEAD STRIPPING AND HOT AIR LEVELLING
1) Tin-Lead Stripping
For Solder Mask Over Bare Copper(SMOBC) Boards the Tin-Lead plating on the
board is stripped prior to solder masking.
2) Hot-Air levelling
The SMOBC boards after solder masking are sent for hot air levelling where the
boards are dipped in molten solder bath and then withdrawn between a pair of
hot air knives to remove excess solder. After HAL, boards are sent to
routing/legend printing as indicated on the F.O.
4.QUAL ITY CONTROL
After all manufacturing operations are completed, the boards are subjected to find
inspection. The work instruction of this area are covered under PCB/QC/WI. Rework
data is collected at final inspection stage.
MASTER FILM PREPARATION
Methods department hands over the pilot blank drilled along with the validated film to
the Film preparation group with necessary instruction like position of thief frame,
dummy patterns for plating control and modification /corrections if any to be
incorporated in the film for the prepration of manufacturing films.
PLATING AREA CONTOL
The copper lead area to be plated for individual codes will be computed by methods
and is issued to the plating shop with necessary instructions to do the sample plating
for confirmation. The plated boards are checked by Methods for correct hole
diameter proper plating thickness for individual PCB codes.
ROUTING TAPE PREPARATION
Routing tape is prepared for the individual codes based on the routing drawing
supplied. A pilot routing is done and is verified for the card dimentions. A routing
control drawing is issued to the routing shop for verification by the operator.
BBT JIG PREPARATION
In PCB shop boards are verified for electrical continuity with the help of Bare Board
Tester. The drill tape for jigs are prepared by Methods and issued to drilling shop to
drill on the glass epoxy laminate which is issued to Q.C.
BOM PREPARATION/CORRECTION AND PLANNING
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
The quality to be processed is planned based on the consumption pattern and feed
back from production. The BOM is prepared on the data available and intimated to
stock control. Procurement action for Methods identified items is taken. Scrutiny is
done for the technical suitability of the offers received. The consumption value of
consumables in production is collected and analysed.
5. PROCESS CAPABILITY STUDY
Process capability study is done based on the the equipment available and provided
Evaluation of the stability of the process to deliver the require quality of product.
Fault report analysis
Fault report raised by PCB production section including fina inspection are
analysed and disposal/corrective action suggested.
Metallography
Here Metallographic cross-section is done to check whether the etching
machine can be qualified. The dispersion test for qualification of Drilling and
Routing machine and incoming raw material inspection is also done here.
Customer Care
Customer complains are analysed and disposal action is suggested. Contract
review meetings are held with Marketing Dept.
6.EQUIPMENT MA INTENANCE
Installation, Commissioning and subsequent maintenance of all production and
production support equipments in PCB plant is done by the equipment maintenance
group in addition to this Maintenance of UPS systems is done by this group. The
activties are covered under procedure EM/PCB/PRO/01.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
RAW MATERIAL FO CUTTING ORDER
CUTTING DRAWING
CUT CUT BLANKS
DRILL TYPE DRILLED BOARDS
ANALYSIS REPORT
CHEMICALS
ELECTRONLESS PLATING BOARDS
DIAZO FILMS CHEMICAL, DRY FILM
IMAGE TRANSFERRED BOARDS
PLATING AREA ANALYSIS REPORT
PLATED BOARDS
CHEMICALS
STRIPPED BOARDS
CHEMICALS
ETCHED BOARDS
CHEMICALS
STRIPPED BOARDS
ORTHO FILMS
SOLDER MASKED BOARDS
SOLDER
HALED BOARDS
ROUTING TAPE
ROUTED BOARDS
QC CLEARED BOARDS
PCB PROCESS MAP
QC
QA
CNC ROUTING
RAW MATERIAL CUTTING
CNC DRILLING
ELECTRONLESS PLATING
PHOTO IMAGE TRANSFER
ELECTRO PLATING
FILM STRIPPING
ETCHING
TIN-LEAD STRIPPING
SCREEN PRINTING
HOT AIR LEVELING
METHODSCHEMICAL LAB
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
RESEARCH AND DEVELOPMENT
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
SCADA
INTRODUCTION
The Supervisory Control and Data Acquisition (SCADA) system plays an important
role in modern system management, which provides centralized data base
management of system control. The system also finds use whenever there is a
requirement of data acquisition and also remote Station Monitoring. It also finds use
in control and analysis of various parameters like voltage and current. Normally, the
requirement is to remotely monitor analog parameters and status of various bi-state
devices as in Railway Electrification Network. Tele commands can be executed for
ON/OFF or open/close function of bi-state devices from the master station. The
system ensures that the communication network is managed in efficient manner
making optimum use of available resources.
The Supervisory Control and Data Acquisition system consists of master
equipments at remote control centre and remote terminal units at each of the remote
stations. The Remote stations are distributed geographically at different locations.
FEP to Unix Server communications is through Optical Transmitter (Fiber Optic
Interface). Front End Processor will execute the Tele-commands (server of RTU
messages) of Remote Terminal Units (RTU). FEP will send Tele commands
received from the Server on priority basis to operate the bi-state devices like circuit
breakers at RTU. In case of RTU not responded for the first call, the Front End
Processor has to repeat the call three times to Remote Terminal Unit. If there is noresponse for third call also then Remote Terminal Unit is declared as RSD (Remote
The Supervisory Control and Data Acquisition system consists of the master station
equipments at the Remote Control Center and Remote Terminal Units at each of the
remote stations).The Remote station defective at FEP. After that only one FEP will
send the call to a Remote Terminal Unit in 3 characters, which will be received
simultaneously by the RTUs. But only one RTU corresponding to the address will
reply. On polling, the processor(FEP) will send analog calls to the RTU and RTU will
respond with analog messages. In case of any change of status in double way status
or Single way status the RTU will send that SW/DW data to FEP on priority basis.FEP has to send acknowledgement for data confirmation for SW, DW messages
after receiving from the RTU.
The Remote Terminal Unit has a unique address and are waiting to be addressed by
the FEP. FEP to server is through Optical Transmitter. Front End Processor will
execute the Telecommand (server to RTU message) on Remote Terminal Unit
(RTU).
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DESIGN METHODOLOGY
REQUIREMENT ANALYSIS
The master station equipment consists of :
Front End Processor (FEP main/standby arbitrator).
Workstation (Computer, graphic terminals and printers)
Panel Processor/mimic panels. UPS
The Remote station telemetry equipment comprises of
Remote terminal units
Necessary transducers
Modules
1) CPU-8085 based
2) Analog modules
3) Status input modules
4) Telecommand execute modules
Front End Processor
This has centralized control which performs monitoring, collection of data from
remote terminals, passing it on to the server or saving the data and carrying out
telecommand signals. It also accepts broadcast messages and general check call
from workstations that are to be transmitted to the remote terminals.
Panel Processor
It acquires data from the Front End Processor and display or mimic panels. Thecommunication of panel processors to Front End Processors is through serial
port at 2400 baud. It is bi-directional and asynchronous.
Mimic Panel
It is used to display ac traction between station using 8 panel processors.
Remote Terminal Uniits:
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Sends data through master station on a call reply basis. There is continuous
exchange of messages between Front End Processors and Remote terminal
Units and the front-end Processors initiates call.
The Front End Processor is connected to the Remote Terminals through a quad
cable on optical/microwave channel. Here a quad cable is used. The maximum
baud rate is 600 bits/second.
TOOLS USED ARE:
TIMER
CREATE
COMNOTIFY
COMSTAT
SCADA hardwareA SCADA system consists of a number of remote terminal units (RTUs) collectingfield data and sending that data back to a master station, via a communicationsystem. The master station displays the acquired data and allows the operator toperform remote control tasks.The accurate and timely data allows for optimization of the plant operation andprocess. Other benefits include more efficient, reliable and most importantly, saferoperations. This results in a lower cost of operation compared to earlier non-automatedsystems.On a more complex SCADA system there are essentially five levels or hierarchies: Field level instrumentation and control devices Marshalling terminals and RTUs Communications system The master station(s) The commercial data processing department computer systemBackground to SCADA 5The RTU provides an interface to the field analog and digital sensors situated ateach remote site.
The communications system provides the pathway for communication between themaster station and the remote sites. This communication system can be wire, fiberoptic, radio, telephone line, microwave and possibly even satellite. Specific protocolsand error detection philosophies are used for efficient and optimum transfer of data.The master station (or sub-masters) gather data from the various RTUs andgenerally provide an operator interface for display of information and control of theremote sites. In large telemetry systems, sub-master sites gather information fromremote sites and act as a relay back to the control master station.
SCADA softwareSCADA software can be divided into two types, proprietary or open. Companies
develop proprietary software to communicate to their hardware. These systems are
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sold as turnkey solutions. The main problem with this system is the overwhelmingreliance on the supplier of the system. Open software systems have gainedpopularity because of the interoperability they bring to the system. Interoperability isthe ability to mix different manufacturers equipment on the same system.Citect and WonderWare are just two of the open software packages available in the
market for SCADA systems. Some packages are now including asset managementintegrated within the SCADA system
Key features of SCADA software are: User interface Graphics displays Alarms Trends RTU (and PLC) interface Scalability
6 Practical SCADA for Industry Access to data Database Networking Fault tolerance and redundancy
Client/server distributed processing
Landlines for SCADAEven with the reduced amount of wire when using a PC to IED system, there is
usually a lot of wire in the typical SCADA system. This wire brings its own problems,with the main problem being electrical noise and interference.Interference and noise are important factors to consider when designing andinstalling a data communication system, with particular considerations required toavoid electrical interference. Noise can be defined as the random generatedundesired signal that corrupts (or interferes with) the original (or desired) signal. Thisnoise can get into the cable or wire in many ways. It is up to the designer to developa system that will have a minimum of noise from the beginning. Because SCADAsystems typically use small voltage they are inherently susceptible to noise.The use of twisted pair shielded cat5 wire is a requirement on most systems. Usinggood wire coupled with correct installation techniques ensures the system will be asnoise free as possible.Fiber optic cable is gaining popularity because of its noise immunity. At the momentmost installations use glass fibers, but in some industrial areas plastic fibers areincreasingly used.
SCADA and local area networksLocal area networks (LAN) are all about sharing information and resources. Toenable all the nodes on the SCADA network to share information, they must beconnected by some transmission medium. The method of connection is known asthe network topology.
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Nodes need to share this transmission medium in such a way as to allow all nodesaccess to the medium without disrupting an established sender.A LAN is a communication path between computers, file-servers, terminals,workstations, and various other intelligent peripheral equipments, which aregenerally referred to as devices or hosts. A LAN allows access for devices to be
shared by several users, with full connectivity between all stations on the network. ALAN is usually ownedand administered by a private owner and is located within a localized group ofbuildings.Ethernet is the most widely use LAN today because it is cheap and easy to use.Connection of the SCADA network to the LAN allows anyone within the companywiththe right software and permission, to access the system. Since the data is held in adatabase, the user can be limited to reading the information. Security issues areobviouslya concern, but can be addressed.
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POWER SUPPLY UNIT
TYPES OF POWER SUPPLIES:
There are two types of power supplies:
1. Linear Power Supplies
2. Switched Mode Power Supplies (SMPS)
Linear power supplies:
The linear power supply is a well known power supply since the advent of
electronics.
The above circuit in fig (2.1) shows a linear power supply. Vin is the
ac main voltage with 50 Hz supply frequency. A conventional transformer
is used to step down the ac main to low voltage of same frequency. This
secondary voltage is rectified and filtered. The resulting dc output is fed
to a series pass transistor. A sample of Vout derived from the potential
divider is compared with the Zener Diode produced reference voltage and
the difference is amplified and used to control the power transistor to
maintain constant output voltage. However this mode of operation
dissipates a large amount of power in the form of heat, consequentlylowering the efficiency of power to 40% or 50%.
Thus, because of lower efficiency, bulky heat sinks and cooling fans,
larger isolation transformers are used to step down the ac voltage. So this
type of power supply is not suited for compact electronic system.
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Switched Mode Power Supply
The disadvantages of linear power supply are greatly reduced or
eliminated by the regulated switching power supply.
The fig shows a simplified block diagram of a high frequency off the line
switching power supply. In this scheme the ac line is directly rectifiedand filtered to produce a raw high voltage be quite small due to high
operating frequency. High the combination of high frequency with the
small size of the transformer, results in compact, light weight power
supplies, with power densities of upto 30 Watt/Cubic in for linear. Coupled
with very wide input voltage range, 90 to 260 volts ac and very good hold
up time, typically 25 ms, the switch has become the choice for electronic
system designers.
Of course there are certain disadvantages associated with switching
power supply, such as higher output noise and ripple, EMI/RFI generation
and higher design complexity. However, with careful design these
problems may be reduced or eliminated.
Advantages of linear and switched mode power supplies:
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LINEAR POWERSUPPLY
Tight regulation band
Very low output noise ripple
Low complexity
SWITCHED MODEPOWER SUPPLY
Very high overall efficiency.
Lower operating temperatureand relaxed heat removalproblems.
Small power transformer size
due to high switchingfrequency
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WIRELESS LAB
MODEM
A modem is a communication device that converts binary signal into
analog acoustic signals for transmission over telephone lines and
converters these acoustics signals back into binary form at the receiving
end.
Conversion to analog signal is known as modulation, conversion back to
binary signal is known as demodulation.
In the terminology used in the RS-232 communication standard, modems
are DCEs, which mean the connected at one end to a DTE(e.g. computer)
device.
Digital modem supports ASIC modem chip PVG310 user
programmable spartan , FPGA & frequency sources.
Analog Modem supports T*IF (350 Mhz).
Suitable for narrowband and broadband wireless application.
Programmable modulation, QPSK, QAM
Concentrated convolution or block convolution inner code with
variable rates.
RS-232 interface for M&C features through NMS. Its wireless flexibility allows a single platform to add a broad range
of wireless markets.
WIRELESS ISM TRANSMITTER
FEATURES:
Supports license free ISM band i.e 2.4-2.48
Provides the user data interfaces 4Hz RS-232, RS-485/RS-422,
Ethernet and USB.
Supports PSK modulation
Supports IEEE 802.15.4 MAC standard
RF interface with built antenna.
RF output power is 0dbm to 28dbm.
Module dimension 7*5*3.5
APPLICATIONS:
Wireless remote monitoring and control
Wireless network management system application
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CAD(Computer Aided Design)Computer-aided design(CAD), also known ascomputer-aided design and
drafting(CADD),is the use ofcomputersystems to assist in the creation,
modification, analysis, or optimization of adesign. Computer-aideddrafting describes the process of creating atechnical drawingwith the use
of computer software.CAD software is used to increase the productivity of
the designer, improve the quality of design, improve communications
through documentation, and to create a database for manufacturing.CAD
output is often in theform of electronic filesfor print or machining
operations. CAD software uses either vector based graphics to depict the
objects of traditional drafting, or may also produceraster graphics
showing the overall appearance of designed objects.
PCB Basics
A standard PCB consists of several layers of fibreglass pressed together,
with places for chips and connections between them called traces. With a
prototyping board, you will receive only the PCB from the manufacturer,
and will need to mount all your components yourself. The two most
common ways to mount devices to a PCB are through hole and surface
mount.
Device Mounting
Through hole mounting consists of drilling holes in the PCB, allowing wiresconnected to the chip to pass through the holes. These wires are then
soldered onto the conducting circles called pads around each hole in the
PCB, forming a solid connection between the chips pin and the PCB pad.
These holes come filled with conducting material (usually copper) so that
traces to the top and bottom pads of the hole are connected to both the
chip and each other without having to solder both sides of the board.
In contrast, surface mounting consists of creating rectangular conducting
pads on the PCBs surface. The chips pins are then soldered directly tothese pads. Obviously, these pads only exist on one side of the PCB,
unlike through-hole.
Of the two methods of mounting components, through hole is much
easier to solder and offers more room for error. However, since surface
mount components are common for production designs while through
hole is mostly used for prototyping, you will often find an abundance of
components in a surface mount package. There may even be components
you require that are not available in a DIP package. Try to have someone
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willing to solder surface mount components for you before you decide to
use them in your PCB design, as the process is quite involved. Successful
surface mount soldering will require at least a fine soldering iron as well
as good technique, but these components were meant to be soldered
using solder paste and oven.
It is also very important that, before you start designing the PCB, you
either have all the components you will be mounting in front of you, or
have detailed schematics of the components and their PCB layouts if
available. It is also a good idea to verify the availability of the required
components. Design your PCB to allow for some margin for error and
perhaps even to accept a similar component if possible. It is very
important that you lay out the pads for your devices correctly.
Traces
Connections between device pads are accomplished by traces, which are
lines of conducting material (usually copper) placed on the surface(s) of
the PCB, acting like wires. Traces must be wide enough to support the
current travelling through them and must be spaced out enough so they
do not interfere with each other (more on this later). Obviously traces
cannot cross or touch at any point. It is also a good practice to avoid
sharp angles in traces (90 degrees or less) since this increases signal
interference.
One of the limitations of a fast turnaround prototyping PCB design is that
you will probably have only two layers of traces (the top surface and the
bottom surface) to work with. This can cause difficulties in the routing of
traces in complicated designs, so special care is needed as the number of
traces needed increases. Some ingenuity is often useful to manually route
traces effectively but auto routing should do a good enough job in most
cases.
To connect a trace from one side of a PCB to the other, a VIA is used. A
VIA is a small hole drilled in the PCB that is filled conductor, linking any
traces connected to it on top to any traces connected to it on the bottom.
VIAs are useful to alleviate routing problems by allowing signals that
cannot be routed on a single side to use the other side or layers of the
PCB.
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Decoupling Capacitors
One of the easiest things to overlook in a design, decoupling capacitors
are a must for almost any high-speed digital logic chip. Decoupling
capacitors are placed in between the power and ground inputs of a digital
logic chip, preferably as close as possible to the chip itself. Thesecapacitors buffer the input power voltage, preventing voltage source
spikes from reaching and damaging the chip, and to reduce the effects of
interference. They also provide localized current to the chip for driving
output lines, making transitions smoother.
Often, chip manufacturers will provide a guide describing how their chips
should be decoupled and how large or small the capacitors doing it should
be. This documentation is unlikely to be included in the datasheet for a
chip with many different models like SRAM. In these cases, there will
most likely be a single document applicable to a wide variety of models.
Measurements
One first confusing aspects of PCB design is the mixing of metric and
standard units. The two most common way of specifying measurements
like pin or pad spacing are in millimetres or mils. Be careful, these are not
the same thing! A mil is the term coined for one thousandth of an inch,
and is obviously a lot smaller than a millimetre (since an inch is much less
than a meter).
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INFORMATION TECHNOLOGY
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PRINCIPLE OF IVRSInteractive voice response refers to technology supporting the interactionof customer with the service provider generally over the telephone lines.When a person wants to access any of the services of the Interactive
Voice Response System, he presses a number through his telephonekeypad. The pressed number appears across the line and the ringdetector circuit senses this ring. After a specified number of rings therelay is activated through the microcontroller, which in turn connects theline to DTMF decoder.The activation of relay causes the number pressed to appear across theDTMF decoder.The decoder decodes the number pressed and then the decoder output ispassed through the microcontroller to the computer.Now, when the caller presses a number, the number pressed is decoded
by the DTMF decoder and passed to the computer through themicrocontroller using MAX232.The computer recognizes the number and accesses the particular file fromthe database to output the voice message.The output voice is passed through the voice card where the digitizedserial data is converted into analog voice form and passed to the line. Thecaller gets the information through the line.
SEQUENCE FOLLOWED IN THE IVRS SERVICE
Caller dials the IVRS service number.
The computer waits for a specified number of ringing tones at the end ofwhich, the connection is established.
The connection is established by lifting the handset of telephone basefrom ONHOOK condition.
Now, a pre-recorded voice greets the caller conforming that the numberdialled corresponding to the particular service.
Next, the menu is presented to the caller again in the voice form, givinghim the various options to choose from.
If the information to be relayed back is confidential, then the systemmay even ask the dialer, to feed in a password number.
The database is accordingly referenced and the necessary information isobtained.
Next, the same information is put across to the user in voice.
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The caller generally given the option to :a. Repeat whatever information was voiced to him.b. Repeat the choices.c. Break the call by restarting ON-HOOK condition
GENERAL DESCRIPTION ABOUT TELEPHONYAny telephone set will always be in any of the conditions mentionedbelow:
ON-HOOKIt is the state whenever telephone handset is placed on the cradle. Duringthis state, the telephone line is open circuit with the exchange and thevoltage of48 V is available on each telephone line from the exchange.
OFF-HOOKThis is the state whenever telephone handset is displaced from the cradle.During this state the voltage level is between 5V to 12 V. Thetelephone OFF HOOK resistance is typically 600 .
SIGNALING TONESDial tone:This tone indicates that the exchange is ready to accept dialed digits fromthe subscriber.The subscriber should start dialing only after hearing the dial tone.
Otherwise, initial dialed pulse may be missed by the exchange that mayresult in the call landing on the wrong number. The dialed tone is 33 Hzor 50 Hz or 400 Hz continuous tones.
Ring tone:When the called party is obtained, the exchange sense out the ringingcurrent to the telephone set of the called party. This ringing current hasthe familiar double ring pattern.Simultaneously, the exchange sends out the ringing tone to the callingsubscriber, which has the pattern similar to that of ringing current, the
two rings in the double ring pattern are separated by a time gap of 0.2sand two double rings patterns by a time gap of 2s.The burst has durationof 0.4s. The frequency of the ringing tone is 133 Hz or 400 Hz.
Busy tone:Busy tone is bursty 400 Hz signal with silence period in between. Theburst and silence duration has the same value of 0.75s. A busy tone issent out to the calling subscriber whenever the switching equipment orjunction line is not available to put through the call or called subscriberline is engaged.
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Number unobtainable tone:The number unobtainable tone is a continuous 400 Hz signal. This tonemay be sent to the calling subscriber due to a variety of reasons. In someexchanges this tone is 400 Hz intermittent with 2.5s ON period and 0.5sOFF period.
Routing tone:The routing tone or call in progress tone is 400 Hz or 800 Hzintermittent patterns. In an electromechanical system it is usually 800Hzwith 50% duty ratio and 0.5s ON-OFF period. In analog electronicexchange it is 400 Hz pattern with 0.5s ON period and 0.5sOFF period. In digital exchange it has 0.1s ON-OFF period at 400 Hz
ADVANTAGES AND DISADVANTAGES OF USING IVRSYSTEMS
ADVANTAGES
The biggest advantage of IVR for small and large organizations is to savetime and money. Answering phone calls takes a lot of time, and not everyphone call deserves the attention of a trained employee. IVR systems cantake care of most of the frequently asked questions that an organization
receives (office hours, directions, phone directory, common tech supportquestions, et cetera) and allow customer service reps, salesmen andtech support specialists to concentrate on the harder stuff. If a largecompany is able to shave even a second off the average length of each
phone call with a live operator, it can save them hundreds of thousands oreven millions of dollars a year [source: Human Factors International]. IVRsystems have the advantage of making callers and customers feel likethey're being attended to, even if it's just by a machine. If you have asimple question, it's better to get a quick answer from a computerizedoperator than to wait ten minutes on hold before talking to a humanbeing. Another advantage is that IVR systems don't sleep. They don't takelunch breaks. They don't go on vacations to the Bahamas. An IVR systemcan be available 24 hours a day to field questions and help customerswith simple tasks. An IVR system can make a small company look bigger.
Some IVR hosting plans even set you up with an 800 number to lookmore official. Subscription IVR hosting plans make it easier for businessesand organizations to use these automated phone services. This is a bigadvantage of days past, when only large companies with bigtelecommunications and computing budgets could afford the hardware,software and staff to run in-house IVR systems.
DISADVANTAGESThe greatest disadvantage of IVR systems is that many people simplydislike talking to machines. Older adults may have a hard time following
telephone menus and lengthy instructions. And younger callers get
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frustrated with the slowness of multiple phone menus.
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SWITCHING AND ACCESS
PRODUCTS
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SMT (Surface mount technology)Mass produced electronic circuit boards need to be manufactured in a
highly mechanised manner to ensure the lowest cost of manufacture. The
traditional leaded electronic components do not lend themselves to thisapproach. Although some mechanisation was possible, component leads
needed to be pre-formed. Also when the leads were inserted into boards
automatically problems were often encountered as wires would often not
fit properly slowing production rates considerably.
It was reasoned that the wires that had traditionally been used for
connections were not actually needed for printed circuit board
construction. Rather than having leads placed through holes, the
components could be soldered onto pads on the board instead. This also
saved creating the lead holes in the boards which added cost to the
production of the bare PCBs.
As the components were mounted on the surface of the board, rather than
having connections that went through holes in the board, the new technology
was called surface mount technology or SMT and the devices used were
surface mount devices, SMDs. The idea for SMT was adopted very quickly
because it enabled greater levels of mechanisation to be used, and it
considerably saved on manufacturing costs.
To accommodate surface mount technology, SMT, a completely new set of
components was needed. New SMT outlines were required, and often the
same components, e.g. ICs were sold in both traditional leaded packages and
SMT packages. Despite this, the gains of using SMT proved to be so large
that it was adopted very quickly.
What are SMT components?
Surface mount devices, SMDs by their nature are very different to thetraditional leaded components. They can be split into a number of
categories:
Passive SMDs: There is quite a variety of different packages used
for passive SMDs. However the majority of passive SMDs are either
resistors or capacitors for which the package sizes are reasonably
well standardised. Other components including coils, crystals and
others tend to have more individual requirements and hence their
own packages.
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Resistors and capacitors have a variety of package sizes. These
have designations that include: 1812, 1206, 0805, 0603, 0402, and
0201. The figures refer to the dimensions in hundreds of an inch. In
other words the 1206 measures 12 hundreds by 6 hundreds of an
inch. The larger sizes such as 1812 and 1206 were some of the first
that were used. They are not in widespread use now as much
smaller components are generally required. However they may find
use in applications where larger power levels are needed or where
other considerations require the larger size.
The connections to the printed circuit board are made through
metallised areas at either end of the package.
Transistors and diodes: These components are often contained
in a small plastic package. The connections are made via leads
which emanate from the package and are bent so that they touch
the board. Three leads are always used for these packages. In this
way it is easy to identify which way round the device must go.
Integrated circuits: There is a variety of packages which are
used for integrated circuits. The package used depends upon the
level of interconnectivity required. Many chips like the simple logic
chips may only require 14 or 16 pins, whereas other like the VLSIprocessors and associated chips can require up to 200 or more. In
view of the wide variation of requirements there is a number of
different packages available.
For the smaller chips, packages such as the SOIC (Small Outline
Integrated Circuit) may be used. These are effectively the SMT
version of the familiar DIL (Dual In Line) packages used for the
familiar 74 series logic chips. Additionally there are smaller versions
including TSOP (Thin Small Outline Package) and SSOP (Shrink
Small Outline Package).
The VLSI chips require a different approach. Typically a package
known as a quad flat pack is used. This has a square or rectangular
footprint and has pins emanating on all four sides. Pins again are
bent out of the package in what is termed a gull-wing formation so
that they meet the board. The spacing of the pins is dependent
upon the number of pins required. For some chips it may be as
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close as 20 thousandths of an inch. Great care is required when
packaging these chips and handling them as the pins are very easily
bent.
Other packages are also available. One known as a BGA (Ball Grid
Array) is used in many applications. Instead of having the
connections on the side of the package, they are underneath. The
connection pads have balls of solder that melt during the soldering
process, thereby making a good connection with the board and
mechanically attaching it. As the whole of the underside of the
package can be used, the pitch of the connections is wider and it is
found to be much more reliable.
A smaller version of the BGA, known as the microBGA is also being
used for some ICs. As the name suggests it is a smaller version of
the BGA.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
STENCIL PRINTER GLUE DISPENSER CHIP SHOOTER
REFLOW OVEN OPTICAL INSEPCTION FINE PLACER
PROCESS CHART
SOLDER PASTEPRINTED ON
PCB
GLUE DOTS DISPENSEDON PCB BETWEEN
SOLDER PADS
CHIPS COMPONETS AREPLACED ON PCB AT
SOLDER PASTE GLUE DOT
LOCATION
FINE PITCH IC LIKE QFPS,
PLCCS AND COILS/
RELAYS PLACED ON PCB
AT SOLDER PASTE
LOCATION
AUTOMATIC OPTICAL
INSPECTION OF
SELECTED
COMPONENT ON PCB
REFLOW SOLDERING ORGLUE CURING
COMPONENTS ARE
PLACED ON THE PCB
DONE
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
BTS (Base Trans-Receiver Station)
Base Trans-Receiver Station (BTS) BTS A-9100, is radio frequency mobile
communication product based on GSM technology. It is a set of equipments that
facilitates wireless communication between user equipment (UE) and a network. A
BTS in general consists of Trans-receiver module, Antenna Network Combiner,
Controller (SUMA) & Alarm Extension System (XIBM). It is a self contained unit for
transmitting / receiving signal for mobile communication.
Types of BTS
1. Indoor BTS 2. Outdoor BTS
3. Dual Band BTS 4. Twin TRX BTS
A BTS in general has the following parts:
Transceiver (TRX)
Quite widely referred to as the driver receiver (DRX), DRX is either in theform of single (sTRU), double (dTRU) or a composite double radio unit
(DRU). It basically does transmission and reception of signals. It also does
sending and reception of signals to and from higher network entities (like
thebase station controllerin mobile telephony).
Power amplifier (PA)
Amplifies the signal from DRX for transmission through antenna; may be
integrated with DRX.
CombinerCombines feeds from several DRXs so that they could be sent out through
a single antenna. This allows for a reduction in the number of antenna
used.
Duplexer
For separating sending and receiving signals to/from antenna. Does
sending and receiving signals through the same antenna ports (cables to
antenna).
http://en.wikipedia.org/wiki/Base_station_controllerhttp://en.wikipedia.org/wiki/Base_station_controllerhttp://en.wikipedia.org/wiki/Base_station_controllerhttp://en.wikipedia.org/wiki/Base_station_controller -
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Antenna
This is the structure that lies underneath the BTS; it can be installed as it is
or disguised in some way
Alarm extension system
Collects working status alarms of various units in the BTS and extends
them to operations and maintenance (O&M) monitoring stations.
Control function
Controls and manages the various units of BTS, including any software.
On-the-spot configurations, status changes, software upgrades, etc. are
done through the control function.
Baseband receiver unit (BBxx)Frequency hopping, signal DSP, etc.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
CDMA (Code Division Multiple Access)
CDMA (Code Division Multiple Access) is a digital wireless technology to provide
mobile communication. CDMA works by converting speech into digital information,
which is then transmitted as a radio signal over a wireless network. CDMA uses a
unique code to distinguish each different call. The receiving device is instructed to
decipher only the data corresponding to a particular code to reconstruct the signal.
This enables many subscribers to share the same frequency band and, at the
same time, without any cross talk or interference.
CDMA WLL technology provides option of limited as well as full mobility to the
customers. This helps to provide faster last mile connectivity, where laying of
cables is difficult.
CDMA CALL PROCESSING
Begin Analog mode Operation
Analog System Acquisition
& Operation
End Analog Mode Operation
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Power Up
Mobile station Acquired or reacquired system
Idle handoff synchronization & system
Overhead info
Receives an Receives a paging channel message
Acknowledgement to an requiring an acknowledgement or
Access channel transmission response; originates a call or
Other than an origination perform registration
Message or page response
Message
Directed to a traffic
Channel
Mobile station
initialization state
Mobile station
Idle state
System
Access state
Mobile Station Control on
the traffic channel state
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
OCB (Organ do Commando B) Telephone
ExchangeIntroduction
Telecommunication Networks Are Constantly Changing. The Rapid Growth Of The Digital
Network, Mobile Network And Intelligent Network And The Proliferation Of New Services
Being Constantly Offered To Subscriber Means That Equipment Must Be Continuously
Adapted To New Requirements. All The New Switching Systems Are Based On Stored
Program Control Concept. The Call Processing Programmes Are Distributed Over Different
Control Organs Of The System And Are Stored In Rom/Ram Of The Units Processor In The
Control Units By Using The Programme And Data Stored In Unit Rom/Ram Process And
Handle Calls. Handling Or Processing A Call Means To Ultimately Establish A Connection In
Between Incoming And Outgoing Ends. Depending On The System The Name And
Architecture Of Control Units And Switch May Change But Basic Criterion For SwitchingMore Or Less Remains Same.
The Alcatel 1000E10 Exchange Also Known By Its Other Name Ocb283 Is Designed To
Cater For Evolving Networks And The Need To Rationalize Equipment Operation. Its
Modular Architecture Means That New Services Can Be Added And Processing Capacity
Can Be Increased Without Interrupting Operation Of The Exchange. Ocb 283 Is A Digital
Switching System Which Supports A Variety Of Communication Needs Like Basic
Telephony, Isdn, and Interface To Mobile Communication, Data Communication Etc. This
System Has Been Developed By Alcatel Of France And Therefore Has Many Similarities To
Its Predecessor E-10. The First Ocb283 Exchange Of R11 Version Came To India In 1993.
At Present R23 and R24 Are Also Being Supplied. The Basic Architecture Remaining Same,More Facilities To Subscriber And Administration Are Supported By Later Versions.
Features of the System
1) It Is a Digital Switching System with Single T Stage Switch. A Maximum Of 2048 Pcms
Can Be Connected.
2) It Supports Both Analogue And Digital Subscriber.
3) The System Supports All The Existing Signalling System Like Decadic, Mf, Cas And Also
Ccitt#7 Signalling System.
4) It Provides Telephony, Isdn, Data Communication, Cellular Radio and Other Value Added
Services.
5) The System Has Auto Recovery Feature. When A Serious Fault Occur In A Control Unit,
It Gives A Message To Smm (Operation & Maintenance Unit). The Smm Puts This Unit Out
Of Service, Loads The Software Of Faulty Unit In A Backup Unit And Bring It Into Service.
Diagnostic Programmes Are Run On The Faulty System And Diagnostics Are Printed On
The Terminal.
6) Ocb283 Has Double Remoting Facility. Subscriber Access Unit Csnd Can Be Placed At A
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Remote Place And Connected To The Main Exchange Through Pcm Links. Further Line
Concentrators Are Placed At A Remote Location And Connected To The Csnl Or Csnd
Through Pcms. This Special Feature Can Meet Entire Range Of Necessities Like Urban,
Semi-Urban And Rural.
7) Various Units Of Ocb283 System Are Connected Over Token Rings. This Enables FastExchange Of Information And Avoid Complicated Links And Wiring Between Various Units.
8) The Charge Accounts Of The Subscribers Are Automatically Saved On The Disc, Once In
A Day. This Avoids Loss Of Revenue In Case Of Total Power Supply/ Battery Failure Or Any
Other Type Of Exchange Failure.
9) Traffic Handling Capacity Of The System Is Very Huge. It Can Handle 8,00,000 Bhca And
25,000 Erlangs Of Traffic. Depending On The Traffic, A Maximum Of 2,00,000 Subscribers
Or 60,000 Circuits Can Be Connected.
10) The Exchange Can Be Managed Either Locally Or Through Nmc Of 64Kbps Link.
11) The Ocb283 System Is Made Up Of Only 35 Different Type Of Cards. This Excludes
Cards Required For Csn. Because Of This The Number Of Spare Cards Required For
Maintenance Purpose, Are Drastically Reduced.
12) All The Control Units Are Implemented Are Implemented On The Same Type Of
Hardware. This Is Called A Station. Depending On The Requirement Of Processing
Capacity, Software Of Either One Or Several Control Units Can Be Located On The Same
Station. For All These Control Units, Only One Backup Station Is Provided, EnablingAutomatic Recovery In Case Of Fault.
13) The System Has Very Modular Structure. The Expansion Can Be Carried Out Very
Easily By Adding Necessary Hardware & Software.
14). The Smm(O&M Units) Are Duplicated, With One Active And Other Hot Standby. In Case
Of Faults, The Switchover Takes Place Automatically. Moreover, Discs Are Also Connected
To Both The Smms, There Is No Necessity Of Changing Of Cables From One To Another.
15) The Hard Disc Is Very Small In Size, Compact And Maintenance Free. It Has A Very
Huge Memory Capacity Of 1.2Gb. The Detail Billing Data Are Regularly Saved In These
Discs Itself, From There It Can Be Transferred To The Magnetic Tapes For The Purpose Of
Processing.
16) There Is No Fixed Rack And Rigid Suite Configuration In This System. It Provides
Greater Flexibility And Adjustment In The Available Space.
17) This System Can Work At A Temperature 5C To 45C, Though The Optimum
Temperature To Work Is 22C.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Subscriber Facilities Provided By Ocb
It Provides A Large Number Of Subscriber Facilities. Some Facilities Are Available To Only
Digital Subscriber And As Such They Can Not Be Availed By Analogue Subscribers. ToAvail These Facilities Subscriber Number Are Given Special Categories By Man Machine
Commands.
I. A Line Can Be Made Only Outgoing And Incoming.
Ii. Immediate Hotline Facility The Subscriber Is Connected To Another Predetermined
Subscriber On Lifting The Handset, Without Dialing Any Number.
Iii. Delay Hotline Facility When Subscriber Lifts The Handset, Dial Tone Is Provided, He
Can Dial Any Number. If He Does Not Dial A Number, Within A Predetermined Time, He Is
Connected To Predetermined Number.
Iv. Abbreviated Dialing The Subscriber Can Record A Short Code And Its Corresponding
Full Number In The Memory. Later To Dial This Number He Has To Dial Only Short Code Of
That Number.
V. Call Waiting Indication When A Subscriber Is Engaged In Conversation And If Getting
An Incoming Call, An Indication Is Given In The Form Of A Tone. Hearing This, The
Subscriber Has Option, Either To Hold The Subscriber In Conversation And Attend The
Waiting Call Or To Disconnect This Subscriber And Attend To The Waiting Call. In The
Former Case He Can Revert Back To The Earlier Subscriber.
Vi. Call Forwarding When Provided, Incoming Calls To The Subscriber Gets Transferred
To The Number Mentioned By The Subscriber While Activating The Facility. This Facility Is
Especially Very Useful For Those Person Who Are Always On Move.
Vii. Conference Between 4 Subscribers The Subscriber A & B While In Conversation, Can
Include Two More Subscriber By Pressing * Button And Dialing Their Numbers.
Viii. Automatic Call Back On Busy If This Facility Is Activated And If The Called Subscriber
Is Found Busy, The Calling Subscriber Simply Replaces The Receiver. The System Keeps
Watch On The Called Subscriber And When It Becomes Free, A Ring Is Given To Both The
Subscribers. On Lifting They Can Talk To Each Other.
Ix. Priority Lines Calls From These Lines Are Processed And Put Through Even When The
Number Of Free Channels Are Within A Threshold Or When The System Is Operating In
Catastrophic Mode.
X. Malicious Call Identification When This Category Is Given To A Subscriber, The Number
Of Calling Subscriber, The Number Of Calling Subscriber To This Number Is Printed On The
Terminal Or Displayed On The Caller Identification Instrument.
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INSTITUTE OF TECHNOLOGY , GURU GHASIDAS VISHWAVIDYALAYA, BILASPUR, (C.G) |
Xi. 12 Or 16Khz Meter Pulses The System Can Send 12 Or 16Khz Meter Pulses On The
Subscriber Line For The Operating Of The Home Meter.
Xii. Battery Reversal The System Extends Battery Reversal When Called Subscriber
Answers. This Is Useful In Case Of Ccbs( Coin Collection Box ).
Xiii. Detailed Billing The System Provides Detail Bills Given Details Of Date, Time, Metered
Units Etc.
Xiv. Absent Subscriber Service When Activated, The Incoming Calls Are Diverted To
Absent Subscriber Service For Suitable Instruction Or Information.
Xv. It Provides 64 Kb/S Digital Connectivity Between Two Subscribers For Data
Communication.
Xvi. This System Provides Facsimile (Fax) Services And Videotext Services Also.
Xvii. This System Also Provides The Facility For Restriction Of The Display Of Calling
Subscriber Number On Called SubscriberS Telephone Terminal Or Caller Id Set. To Avail
This Facility The Subscriber Has To Be Given A Category Like Some Vvips Or Some
Beurocrats.
Xviii. User To User Signaling The System Permits Of Mini Messages Between Calling And
Called Subscribers During Call Setup And Ringing Phase.
Xix. Terminal Portability During The Call A Subscriber (Calling Subscriber As Well As
Called Subscriber) Can Unplug Telephone Instrument, Carry It To Some Other Place OrRoom And Resume The Call Within 3 Minutes
Xx. Listing Of Unanswered Calls The Number Of Calling Subscribers, Who Calls During
The Absence Of Called Subscriber, Are Recorded In Called SubscriberS Terminal. The
Called Subscriber Than Check Up These Numbers And Call Them Back, If He So Wishes.
Xxi. This System Provides Two Type Of Isdn Connections To The Digital Subscriber, One Is
Of 2 B + D Line (2 Voice Channels Of 64Kbps & I Data Channel Of 16Kbps) Type And Other
Is Of 30 B + D Line (30 Voice Channels Of 64Kbps & 1 Data Channel Of 16Kbps) Type.
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Subscriber Access Unit
Subscriber access unit (CSN) is so designed that they can be equipped with analog
or digital subscriber or both. The cards for both are different but they can be
equipped in any slot of the shelf.
CSN can be placed either in EXCHNAGE switch room or at a remote location. CSN
is known as CSNL or CSND.
Architecture OF CSN: The CSN have one BASIC RACK and up to 3 Extension
Racks. The architecture can be divided into parts:-
DIGITAL CONTROL UNIT(UCN):-
1: Control & connection unit (UCX)
2: Auxiliary equipment processing group (GTA)
Funct ion Of Contro l Units:
Multi resister (MR):- Call handler setup and release of call.
Translator (TR):- Translation of digits, databanks of subscriber & circuits in
files.
Marker (MQ):- Message distribution between common control & connection
units.
Charger (TX):- Computing the charges of a call, keeping meter.
Matrix System Handler (GX):- Process & make connection in switching matrix
on the order from MR or MQ.
Common Channel signaling Network Controller:Manage the CCS#7 network
for signaling.