it i report arpita

7/28/2019 It i Report Arpita

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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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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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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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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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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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& 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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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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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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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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CDMA (Code Division Multiple Access) ............................................................................................. 51

OCB (Organ do Commando B) Telephone Exchange ........................................................................ 53


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TELEPHONE AND DEFENCE

PRODUCTS


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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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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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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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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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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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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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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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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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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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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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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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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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RESEARCH AND DEVELOPMENT


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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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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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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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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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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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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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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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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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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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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.

it i report arpita

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