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[PAKISTAN

TELECOMMUNICATION

COMPANY LTD]

[INTERNSHIP REPORT]

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IN THE NAME OF ALLAH, MOST GRACIOUS, MOST COMPANSSIONATE.

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INTERNSHIP REPORT ON PTCL

Pakistan Telecommunication Company Limited

(PTCL)

PREPARED BY:

M. UMAR KHALID (09TL41)

B.Sc. Telecommunication Engineering

UNIVERSITY COLLEGE OF ENGINEERING & TECHNOLOGY

THE ISLAMIA UNIVERSITY OF BAHAWALPUR, PAKISTAN

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CONTENTS

Sr. No Name Page

1 Who is who and what is what? 8

2

2.1

2.2

2.3

2.4

2.5

Services provided by PTCL Optical fiber services to the private sector

Services for corporate customers

Home and personal

Business services

Carrier services and wholesale

9

9

10

11

12

12

3

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3. 8

MDF( Main distribution frame) PTCL Architecture

Networks

MDF (Main Distribution Frame) JPX-202/3219 (Huawei)

Joint Cable Connectors

Faults detection and checking

DSL Connection in Exchange

Voltages and currents in MDF

Documents for New Connection

13

13

14

14

15

15

16

17

17

4

4.1

4.2

4.3

4.4

4.5

4.6

4.7

4.8

4.9

4.10

DSL( digital line subscriber) DSL Introduction

Types of DSL

DSL Technologies Speed and distance Chart

ADSL Basic Architecture

DSL Modem

DSLAM (Digital Subscriber Line Access Multiplexer)

BRAS (Broadband Remote Access Server)

Relations

LQT measurements for 2mb DSL

Difference b/w ADSL & DSL

18

18

18

18

18

19

20

20

21

21

21

5

5.1

5.2

5.3

5.4

5.5

5.6

5.7

5.8

5.9

NGN( Next generation network) Block Diagram of NGN BWP

Overview

Soft switch

UMG (Universal Media Gateway)

Hardware Division

MSAN (Muti-Service Access Node)

SS7 (signaling system. 7)

E1

Difference in Hub, Switch, Bridge, & Router

22

22

22

23

23

25

25

27

27

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6

6.1

6.2

6.3

6.4

6.5

Alcatel Location

Block Diagram of Alcatel BWP

Main Control Station (SMC)

Auxiliary Equipment Control Station (SMA)

Trunk Control Station (SMT)

29

29

30

30

34

38

7

7.1

7.2

7.3

7.4

Transmission Types of transmission Media

Guided media

Wireless (Unguided Media) Transmission

Factors to select media

41

41

42

43

47

8 Reference Page 48

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PREFACE

This report is the practical part of the most vital practice of our B.Sc

Engineering program. The sole objective is to familiarize the student with

the practical manipulation of Engineering Sector. This report has been

written to know how big organizations like PTCL work with their teams to

achieve their common goals.

In the first phase of the report there is the general introduction

about the employers in the CTX Bahawalpur, then the mission regarding

technical and operational network, different services and then there is some

detail of the hardware used in the Telecommunication sector by PTCL.

M. Umar Khalid

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ACKNOWLEDGEMENT

In the name of Almighty Allah who is most merciful, and who give us strength

to write this internship report in a different way.

We extend our heartiest thanks to our seniors, colleagues, and subordinates who

assist me on every occasion to enable me to write this report.

I pay special homage to the following persons.

� Mr. Shahrukh Rafi Abbasi (Business Manager)

� Mr. Masood-ul-Rauf (Assistant Business Manager)

� Mr. Ubaid-Ur-Rehman

� Mr. Akram

� Mr .Nawaz Abbasi

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1. Who is who and what is what?

There are technician and officers which deals the customers problems. Each person has its own work.

1) Mr. Sohail (BB Technical 1 BNCC):

���� All orders of PTCL connections are enter in the computer here.

���� Allot number, its cut off or restore the number according to the number.

2) Mr. Ghulam Yaseen(Technical officer CMS( Complaint Management system)):

���� Fault of the telephone and DSL are entered here.

3) Mr. Munawar Rauf (POC (person of coordinator) coordinator):

���� DSL documents are submitted here.

4) Mr. Tariq:

���� Tells information’s about problems in DSL.

���� Detect the faults in DSL.

���� Faults are checked and correct here in this war room.

���� NPC (Network phone connection new version of NTC) is here.

5) Mr. Muhammad Sajid Mahmood (Engineer Supervisor):

���� OSP maintenance (Cabinet, DP, pole etc).

6) Mr. Masood-ul-Rauf (Assistant Business Manager):

���� Assign the technician of war room to deal the customer problems.

���� Supervisor of MDF.

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2. Services Provided by PTCL

2.1 Optical fiber services to the private sector: Pakistan Telecommunication Company Limited not only Provides Conventional telephone

facilities, it also offers optical fiber services to the private sector. We will briefly discuss

below the product lines being offered by the PTCL. Basically PTCL divide their services into

two parts:-

• Services for consumers

• Services for corporate customers

I. Services for Consumers:

These services are basically for the common users (Individual/home users) those use telephone in

their home/work place and they are basically non business users.

a) New Telephone Connections:

As mentioned earlier, PTCL is presently the only telecom company, who provided fixed-line

telephony in the country. So whenever, any Private business concern or any individual needs a new

telephone connection for provision of telephone service.

b) Value Added Services:

CLI (Caller’s Line Identification) it allows customers to identify the caller before picking up the

phone receiver. To subscribe to Customer needs a telephone set with display capability or a CLI

device at phone.

���� Advantages:

� Check on obnoxious calls � Complete record of incoming / outgoing calls with time & date.

i. PREPAID CALLING CARDS:

PTCL calling card is the most popular choice of millions of customers all over the country. It

is now available with balance transfer facility and follow on call facility.

� Comes in easily affordable denominations of

Rs. 100, 250, 500, 1000 and 2000.

� Easy to use from any PTCL digital phone

(Dial 1010)

� Fast and easy, nationwide and international access

� 24 hours customer services through toll free number

(0800-80800)

ii. E-BILL PAYMENT: Billing system is a part of customer services so providing connivance to its valuable customers

PTCL launched a new billing service which is available through “ PTCL Calling Card” . This

service is basically providing billing solutions for the users.

���� Advantages:

� Customer can save his time by paying his bill on

phone

� Customer can pay his bill whenever he wants

iii. DIGITAL FACILITIES:

PTCL offers a variety of features to digital exchange customers like

� Call Transfer on (a) Busy (b) No Reply

(c) Immediate

� Abbreviated Dialing

� Wake up call

� Call Waiting

� Don’t Disturb

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II. SERVICES FOR CORPORATE CUSTOMERS:

PTCL is striving hard to facilitate its valued corporate customers at each level of service.

PTCL offers a host of unmatched services to suit the needs of the Corporate Customers. The list of

Corporate Services is given as under. For more information regarding any of the following services,

PTCL Corporate Customer Centers can be contacted.

IN BASED VALUED ADDED

SERVICES

VALUED ADDED SERVICES

� 0800- Toll Free

� PTCL calling cards Domestic and

international

� Premium Rate Service- 0900

� Virtual Private Network

� Universal access Number (UAN)

� Universal internet number (UNI)

� ISDN PRI

� Teleplay (ISDN/BRI)

� Local

Domestic/ International Leased

Bandwidth and point Leased Lines

(DXX)

� Local Leased Circuits ( 2Wires/4

wires) DXX

� Digital facilities

� Digital subscriber loop (DSL)

� Co location

� Call centers (new)

���� Universal Access Number (UAN):

UAN (Universal Access Number) service is ideal for organizations Engaged marketing of products or

services. Here is a list of business that can avail UAN Service.

� Banks

� Newspapers

� Airlines

� Hotels

� Insurance

� Credit Card Companies

� Travel

� Shipping Lines

� Trading Companies

� Fast Food Outlets

� Consumer Products

Companies

� Courier Services

� Utility Services

� Stock Brokers

���� Voice Messaging Service (VMS):

� With PTCL Messaging Service, you can have all for (or Desired) calls recorded when you are

absent, busy on phone or do not want to attend the calls for any reason. You can, later on at your

convenience, retrieve all recorded messages from any telephone anywhere in the country.

� Security of message is ensured against eavesdropping through subscriber controlled password.

� PTCL VMS is designed for those who do not want to miss a call or Fax because that can be

beneficial.

� Great for anyone owning a telephone or Fax, at home or business.

� Much more powerful and flexible than answering machine due to Message options available in

your voice mail system.

Features: � Call answer

� Fax

� Messaging

� Notification

� Capacity 10 messages

���� PTCL Messaging Plus

� PTCL MESSAGING PLUS is designed for small and medium business enterprises having

problems with managing telephone message.

� PTCL MESSAGING PLUS will definitely handle these problems for you. Advanced messaging

features save time, make you truly mobile and increase productivity.

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� Essential for time-conscious executives, frequent travelers and Professional groups.

Feature: � Call answer

� Co- Location Centers

Pakistan Telecommunication Company has taken land mark decision to establish co location centers

throughout the country.

Benefits:

� Easy access to local &

international connectivity

� Quick deployment of services

� Higher reliability and quality of service

� Full connectivity under one roof

� Just plug in and

start business

Target market:

� IT companies � Telecom data companies

� Virtual Private Network (VPN): Communication is the secret of success in today’s highly competitive market. When it comes to

enabling your enterprise, your communication got to be instant, fast and hassle free. The answer to

this corporate need is virtual private net work.

� ISDN BRI/PRI:

It is a near broadband experience suitable for household and small/medium sized

organizations.

Features:

� Faster and clear voice

� Fax and data communication

on a single phone

� PRI provides thirty 64 kbps

user channel plus two 16 kbps

signaling channel

� Cost effective

� BRI provides two 64 kbps

user channel plus one 16 kbps

signaling channel

2.3 Home and Personal:

• 3G EVO Tab

Introducing Pakistan’s First 3G Enabled Smartphone Android Tablet—3G EVO Tab.

• EVO 3G Wireless Broadband

EVO 3G Wireless broadband is the pioneer of 3G Wireless Broadband service in Pakistan.

Launched in June 2009 - EVO has started the revolution of the internet evolution in Pakistan.

• Landline

Provide the facility of Landline to connect nationwide and international wide with the

peoples.

• Broadband PTCL Broadband is the largest and the fastest growing Broadband service in Pakistan.

• Smart TV: Employing the IPTV (Internet Protocol TV) technology, PTCL brought Pakistan in the list of

a few countries across the globe that offers this state of the art interactive TV service to its

subscribers.

• Vfone:

PTCL provides Pakistan Largest wireless network based on CDMA technology.

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• Dialup:

Enjoy Phone-n-Net innovative service with nominal charges.

2.4 Business Services:

• Business Connectivity:

PTCL’s business connectivity offers secure, reliable and integrated end to end domestic and

global connectivity solutions to cater for the demands of corporate and enterprise users.

• Business Communication: PTCL’s communication product portfolio is tailored to help business enterprises gain

productivity advantages by offering a suite of powerful convergence, presence-enabled applications.

• Managed Services:

PTCL’s Managed Network Services is a comprehensive solution for those corporate

customers which are aimed at satisfying the essential needs of telephony/voice, data and security

needs.

• Hosted Solutions: Get your e-business up and running quickly for competitive advantage. PTCL offers its

clients a combination of business acumen and technical expertise that your business can never

exhaust. With us, your infrastructure, applications and systems are maintained by certified experts

with experience to make your environment meet and exceed the...

• Business Security: Provide the services with business security.

2.5 Carrier Services & Wholesale:

• Wholesale Services:

PTCL customers can now provide services to their clients without undertaking large scale

investment in infrastructure or developing expertise in running their own networks.

• Telecom Operators: Extend the boundaries of your reach.

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3. MDF (Main Distribution Frame):

3.1 PTCL Architecture:

• PTCL Exchange The Exchange is the building where the local exchange switch resides. A CO’s switch may serve

telephone service subscriber in a very narrow geographic area such as a single large building.

• Distribution Point (DP)

From user to Distribution Point Drop Wire is used. And low- medium density copper cable (2-300

pairs) from DP to Distribution Frame. New building can be built and DPs are used to provide them

connection Instead to direct connection to Exchange.

• Distribution Frames (DF) Distribution fames surround the CO. They are high density copper cable (50-1500 pair) Primary

Cable. Usually all connection to a distribution frame are copper. It allows the telephone company to

use High Density Copper Cabling.

• Main Distribution Frames (MDF)

MDFs are distribution frames that have some smart switching in them. Usually, this equipment has

been placed to provide the facility of DSL for access to use Internet. With the help of DSLAM

Internet is enabling in MDFs for particular user.

3.2 Networks There are two types of networks

i. Internal network: It is consisted of connections of Exchange to MDF and MDF to cabinet.

ii. External network: It is consisted of connections of cabinet to DP and Drop line to subscriber.

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Cable system:

There are three types of cables are use for the transmission and receiving of data transmission

i. Main Cable System (Primary Cable): It is having cables from exchange to main

distribution points, e.g. cabinets or subscriber’s distribution frame in multi-story buildings. It

is highly density copper cable. Primary cable has 300/400 pairs while Secondary cable has

600/800 pairs.

600 pair’s Primary cables

ii. Distribution Cables System (Secondary Cable): This is having cables from main distribution

point (e.g. cabinets) to subscriber distribution points e.g. DP boxes.

Secondary Cable Drop Wire

Two types of cables are used in the distribution cable system.

a. Polyethylene insulated copper cable having diameter of 0.4mm or 0.6mm but this PTCL

exchange is using cable having diameter of 0.4mm. It is low density copper cable. 0.4mm

cable is used b/c it is easily joinable and is cheap. 0.6 mm cable is not b/c it is difficult to joint

and costly.

b. OFC (optical Fiber cable) is mostly used in Islamabad and Lahore. But it is not used mostly

in Pakistan b/c it need regular power supply but there is load shading issues so that’s way it is

not. But OFC can transmit more data than copper cable. As 1 Fiber optics can support 7890

channels. It transmits data with the speed of light.

3.3 MDF (Main Distribution Frame) JPX-202/3219 (Hawaii):

MDF has two sides

i. Inside

ii. Outside

Inside connects the MDF to required switching Exchange NGN while outside connects the MDF

to the cabinet. And inside and outside of the MDF are connected to each other through jumper wire.

Inside of MDF: Inside of the MDF is consisted of NEs which has one pair of jumping wire (Switching board

cable). The connection b/w these wire is horizontally connected by punching tool. PG (permanent

Glow) is inserted b/w the NEs to block or disconnection some subscriber from switching exchange

and cabinet.

Outside of MDF: Outside of the MDF is consisted of the multiple racks of 15 tags having 100 fuses in one

vertical. Fuses show the subscriber connections. Outside of the MDF is connected to the inside of the

MDF by jumping wire. Outside of the MDF have two wires which have vertically connection.

Exchange Cabinet

Cabinet Subscriber Distribution

point (DP)

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MDF belonging to which switching room:

This MDF belongs to switching exchange of NGN Exchange.

Local Exchange: MDF room has its own local exchange which handles the telephone numbers within this PTCL

exchange. I.e. switching room, Alcatel, MDF, officer telephones numbers, war room telephone

number and optical fiber telephone numbers etc.

Types of Exchanges in Bahawalpur:

1) NGN

2) ALCATEL

3) EWSD

SNR of Cable:

• S/N is mostly used to measure how much a signal has been corrupted by noise.

• Mostly SNR is checked before providing DSL connection.

• SNR should be b/w 1 to 9 for telephone and DSL.

• No of joints in a cable should be less.

• The higher the ratio, the greater the resulting clarity.

3.4 Joint Cable Connectors:

1. U-Y connector

U-Y connector:

They enable connecting wires without the need of isolation stripping. They are filled with gel, which

protects wires from corrosion. UY connectors should be used for wires with external coat up to

1.52mm in diameter and 0.4-0.7 wire diameter. The Sealant used in the connector provides the most

effective water & moisture protection. It connects more than 25 pair of solid copper wires at one time.

3.5 MDF Faults, Detection and Checking:

Faults occurring in primary/ secondary cable are due to following reasons:-

1. Jumper Loosing

2. Jumper Break

3. Contact Fault

4. Faulty DSL Port

5. Switch room Fault

6. Fault in Fuse

i. Drop line cable is checked by fault locator if there is no fault. Then fault may be in DP.

ii. DP connection is checked by checking dialing tone on the telephone. If there is dialing tone then

there is no fault. If there is not dialing tone then the DP connection has fault. Then new

connection in DP is assigned by punching tool. If still now the telephone is not in working state.

Then fault may be cabinet.

iii. Secondary cable is checked by fault locator if there is no fault then cabinet connection has fault.

Then fault may in cabinet.

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iv. The dialing tone is checked in cabinet if there is dialing tone then there is no fault. If there is no

dialing tone the fault may be in MDF.

v. MDF required vertical cable pair connection is checked by dialing tone. If there is no dialing tone

then vertical cable pair is changed. If there is the dialing tone then there is no fault so the fault

will be in switching exchange.

vi. Switching exchange power supply, cards etc. is checked and changed. Then card is sending to be

repaired in required manufacturing company

3.6 Connection in Exchange:

Home

3.7 Voltage and Current at MDF:

ON Hook Off Hook When bell is ringing When bell is not ringing

Voltage 49 v 13.6 v 53.1 vDC /139 vAC 53.1 vDC /116.2 vAC

Current 0.130 mA 48mA 0.9 mA 0.9 mA

3.8 New Telephone Connection:

Document required for new connection: i. NIC Copy

ii. Property Deal (Rent Agreement+ NIC of House owner if a person is living on Rent)

iii. Demand Notice(With 3 Months line rent in Advance)

Exchange

Switching

room N.E Cabinet Distribution Frame

DSLAM

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4. DSL (Digital Subscriber Line):

4.1 DSL Introduction:

DSL is a family of technologies that provides digital data transmission over the wires of a local

telephone network. DSL originally stood for digital subscriber loop. DSL service is delivered

simultaneously with regular telephone on the same telephone line. This is possible because DSL

uses a higher frequency. These frequency bands are subsequently separated by filtering.

The data throughput of consumer DSL services typically ranges from 256 Kbit/s to 40 Mbit/s in the

direction to the customer (downstream), depending on DSL technology, line conditions, and service-

level implementation.

4.2 Types of DSL:

• ADSL ( Asymmetric digital subscriber Line (Most popular))

• HDSL (High Bit rate digital subscriber Line0

• IDSL (ISDN based digital subscriber Line)

• VDSL( Very High Speed digital subscriber Line)

4.3 DSL Technologies Speed and distance Chart:

The chart below provides a comparison of the various DSL technologies

DSL Type Max. Send Speed Max. Received Speed Max. Distance

ADSL 800 kbps 8 Mbps 18,000 ft (5,500 m)

HDSL 1.54 Mbps 1.54 Mbps 12,000 ft (3,650 m)

IDSL 144 kbps 144 kbps 35,000 ft (10,700 m)

VDSL 16 Mbps 52 Mbps 4,000 ft (1,200 m)

4.4 ADSL Basic Architecture:

4.5 DSL Modem:

A Digital Subscriber Line (DSL) modem is a device used to connect a computer or router to a

telephone circuit that has Digital Subscriber Line service configured. Like other modems, it is a type

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of transceiver. It is also called a DSL Transceiver or ATU-R (for ADSL Transceiver Unit-Remote).

DSL modem working as a bridge does not need an IP address; it may have one assigned for

management purposes. A DSL modem modulates high-frequency tones for transmission to a Digital

Subscriber Line Access Multiplexer (DSLAM), and receives and demodulates them from the

DSLAM. A single telephone line can be used for simultaneous voice and data with a DSL modem

whereas a voice-band modem precludes simultaneous voice traffic. Most DSL modems are external to

the computer and wired to the computer's Ethernet port, or occasionally its USB port. Internal DSL

modems with PCI interface are rare but available. DSL modems use frequencies from 25 kHz to

above 1MHz in order not to interfere with voice service. Voice-band modems use the same frequency

spectrum as ordinary telephones, and will interfere with voice service - it is usually impossible to

make a telephone call on a line which is being used by a voice-band modem.

Used Equipment:

DSL Modem

SN=E29EB6D14870

Power= 12v= 500mA

Date=Jun 2011

ZTE Corporation

ADSL CPE

ZXDSL 83IC11

Made in china

ADSL Splitter

SP-206

Rosette has four cables blue,

yellow, black and red.

Connection:

Phone

DSL Modem

PC1 PC2 PC3 PC4

4.6 DSLAM (Digital Subscriber Line Access Multiplexer):

The Digital Subscriber Line Access Multiplexer or DSLAM is a mechanism at a phone company’s

central location that links many customer DSL connections to a single high speed ATM line. It takes

connections from many customers and aggregated them onto single high capacity connection to the

Rosette ADSL

splitter

On/off

Power

LAN1 ADSL MODEM

LAN2

LAN3

LAN4

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internet. They are generally flexible and able to support multiple types of DSL in a single central

office and different varieties of protocol and modulation. It may provide additional functions

including routing or dynamic IP address assignment for customers.

DSLAM Architecture:

DSLAM shelf contain card and each card contain 64 connections and so a complete shelf contain that

contain 14 cards would have 896 connections/subscribers.

4.7 BRAS (Broadband Remote Access Server):

The Broadband Remote Access Server (B-RAS) is a key component of DSL broadband access

networks that serves as an aggregation point for subscriber traffic (IP, PPP and ATM) and provides

session termination (PPPoX, RFC 1483) and subscriber management functions such as authentication,

authorization, accounting (AAA), and IP address assignment.

Triggered by the new functional requirements that Triple-Play service delivery imposed on the DSL

network infrastructure and devices, modern B-RASs started to provide advanced services beyond

traffic aggregation

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4.8 Relation b/w DSL modem, DSLAM and BRAS:

4.9 LQT (Line Quality testing) meter reading for 2MB DSL:

Uplink Downlink

DSL SNR 25.00 dB 42.30 dB

Line Attenuation 0.00dB 1.00dB

Actual Rate 636kbps 2557kbps

Maximum Rating

936kbps 28288kbps

4.10 Difference b/w ADSL & DSL:

ADSL have different uplink and downlink rate while DSL have same uplink and downlink rate.

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5. NGN (Next Generation Network):

NGN the Next Generation Network will be the future of all telecommunication Engineers. These

switches which are categorized as Networks can integrate and Handle networks of different

technologies. For example it can handle a land line Network, a data network, a VOIP network and

even a CDMA network at once. NGN is the next step in telecommunication technology. The

Telephone system started up with direct connections to all users. With the expansion new switching

techniques were required. In theory normally we learn as “Switching developed in 4 stages.

1. Manual switching

2. Mechanical switching

3. Semi Electronic Switching

4. Electronic Switching- Stored Program Control”

But the future is here today. Sri Lanka Telecom has taken the giant leap to bring the newest

technology in to their system in parallel with the developed and powerful nations in the world. With

this we can say there are five systems.

5. Packet switching using Routers.

The new system can be called as an information transfer system rather than telephone System. That is

because it can function as a circuit switch, or a video interworking Gateway.

5.1 Block Diagram of NGN BWP:

5.2 Overview: NGN is a service oriented network. It provides an independent service system by splitting the service

module from the call control and the call control from the bearer. That is the services provided to each

subscriber are handled from a database at central control where as in a normal system the services are

defined from where it is connected. Control is merely a place where some information in processed

and send back some Instructions. The access point to the user equipment is merely a packet creation

point. In this way, it frees the service from the original network model. NGN employs open and

integrated network structure. With abundant service Models, NGN is able to provide a variety of

services, such as voice, data and multimedia services, or integrated services. Like in the normal

telephone system the entire system can be divided in to four areas.

• Edge access

• Core switching

• Network control

• Service management

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5.3 Soft switch:

A Soft switch is the centrally located device which is used in telecommunications for connecting the

telephone calls over the various phone lines totally under the supervision of computer software

running on one system .physical switch board are used as the main hardware that acts for carrying

calls from one line to another line. These are the routes for the traveling of signals. If we talk about

the soft switch technology it is widely used in the field of networking and telecommunications in all

local and broad systems.

Call Agent: The call agent is the first part of the soft switch; this part takes care of the sequential functions such as

bilking, call routing, transferring signals, call service and the other minor functionalities. A call agent

can also control the functioning of the other part of Soft switch with the connections over the Transfer

control Protocol (TCP) and internet protocol (IP) some times.

Media Gateway: The second part of the soft switch is called media gate way which is responsible for the different types

of digital streams that works collectively in the creation of end to end for the control of voice and call

over the line. Many interfaces are involved in it which is used for connecting the media to the PSTN

networks such as DS1, DS3 and sometimes E1 and US and No us networks. The call agent may

control the functioning of the media gate way for connecting the media streams and also for the

interfaces in keeping them transparent to the end users of the phone lines.

Benefits of Soft switch:

• Unlike he point devices soft switch has remarkable benefits for the users who are using this

technology. Some of the advantages are listed below.

• Soft switch has higher scalability. They usually work very wickedly by just handling the control

part of the server saving the rest of the switch for the other purposes. They can handle more

clients for the packet data switching.

• No specific hardware is required for the soft switch they are completely platform independent

which is very attractive feature of these switches .they can act well in any computer server

environment.

• Soft switch can be extended by just purchasing the extension license and the controlling

connection over the IP. Sometimes PBX support or card is required for the expansion of the soft

switches in the wide areas.

• Some of the soft switch vendors provide open source to be used by other developers and end users

even .this can help the developer and other programmers to enhance the existing code provide in

the open source.

• Its installation is very easy. It also allows remote installations for its user. Just remote access with

the system containing the installed software set up. Its management is also easy. No extra

maintenance is required for the soft switches.

• Soft switches also provide the extra software based functionalities that no other networking

device provides such as voice mails, call record, call billing etc., all this happens via software.

5.4 UMG (Universal Media Gateway):

The Universal Media Gateway is one of the main equipment in the Access subsystem of the NGN. In

the current implementation of the system in the country this is the main Access system that is being

used since it has multiple functions. It is the most economical solution when the telecom network is

part PSTN and part NGN. Some of the main features of the UMG

• It supports interworking between different networks

• It provides conversion function between different formats of traffic

• Function as a Trunk gateway (TG) and as an Access gateway (AG)

• It has an embedded signaling gateway (SG).

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UMG8900 can be divided into two parts according to its functionality. This help to understand the

system better.

Types of UMG: i. Service switching module (SSM)

ii. User access module (UAM)

Service switching module (SSM):

It processes the formats of various types of traffic flow. It functions as a TG connecting the PSTN

system with the NGN. This is what gives a subscriber in the NGN the chance to call one in PSTN or

any other network even though they work in different ways. In the Absence of a connection with the

switch it can act as a switch in NGN. This gives it the standalone capability and intern more

reliability. Service switching module (SSM) consists of 4 parts

• Main control frame – Management and maintenance functions of the device and supports

service access and process simultaneously.

• Service frame – Process services requested by user

• Central switching frame – Handles Multi-frame cascading function

• Extended control frame – When the device is at maximum capacity. The Extended frame

does not support access and process functions of user Services, But provides connection

management and control function.

User access module (UAM): This is the access point currently provided by Hawaii for the users that are in the NGN. The

instrument can be at the UMG itself or function as a RSU from a distant place. It provides integrated

access function for both narrowband and broadband users. It can even function as an AG if an IP

connection is provided Card structure of the UMG8900

1. Sysyetm Management Boards OMU- Operation Mintance unit

MPU- Main Control unit

CMF- Connection management unit front

NET- packet switch net board

CLK- clock board

CMB-connection management unit back

PPB- protocol processing unit

1. IP interface process Board E8T-8xFE

E1G-1xG

HRB-High speed routing board

2. Signalling Boards SPF- signalling processing board

3. TDM interface proces TNU- TDM switch Net Unit

TCLU- TDM convergence & link unit

E32- 32xE1

S2L- 2xSTM-1 optical

2. Voice Process Board

VPU- voice process unit

SRU- signal resource unit

Cascading Board FLU-front link unit

BLU- back link unit

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5.5 Hardware Division:

UMG8900 hardware system can be divided into the following subsystems according to their function.

1. Operation and maintenance subsystem

2. Gateway control subsystem

3. TDM access and switching subsystem

4. Packet processing subsystem

5. Service resource processing subsystem

6. Subscriber access subsystem

7. Signaling forwarding subsystem

8. Clock subsystem

9. Cascading subsystem.

5.6 MSAN (Multi-Service Access Node): A multiservice access node (MSAN) is a device typically installed in a telephone exchange (although

sometimes in a roadside serving area interface cabinet) which connects customers' telephone lines to

the core network, to provide telephony, ISDN, and broadband such as DSL all from a single platform.

Prior to the deployment of MSANs, telecom providers typically had a multitude of separate

equipment including DSLAMs to provide the various types of services to customers. Integrating all

services on a single node, which typically backhauls all data streams over IP or Asynchronous

Transfer Mode can be more cost effective and may more quickly provide new services to customers.

Typical outdoor MSAN cabinet consists of Narrowband (POTS), Broadband (XDSL) services,

batteries with rectifiers, optical transmission unit and copper distribution frame.

MSAN concept: A MSAN (multi-service access network) can be defined as a single piece of access equipment that can

provide multiple types of services to a range of different customers. MSANs were originally designed

to be placed in a small community to address all its communications requirements. Traditional designs

had a range of slots to accommodate different types of line cards and dual busses to handle both TDM

and data. Today the principle stays the same, but new technology deployed on products--such as the

Marconi Access Hub--allow for any card in any slot; high-density combination DSL and POTS line

cards; and media gateway functionality that allows seamless interworking with soft switches for

packetized voice delivery.

5.7 SS7 (signaling system. 7):

SS7 is a critical component of modern telecommunications systems. SS7 is a communications

protocol that provides signaling and control for various network services and capabilities. While the

Internet, wireless data, and related technology have captured the attention of millions, many forget or

don't realize the importance of SS7. Every call in every network is dependent on SS7. Likewise, every

mobile phone user is dependent on SS7 to allow inter-network roaming. SS7 is also the "glue" that

sticks together circuit switched (traditional) networks with Internet protocol based networks.

SS7 Technology: SS7 signaling is a form of packet switching. Unlike circuit switching, which utilizes dedicated data

"pipes" for transmission of information, packet switching dynamically assigns "routes" based on

availability and "least cost" algorithms. Another example of packet switching is TCP/IP, the protocol

used for routing messages over the Internet. Unlike the Internet, which utilizes a vast public "web" of

interconnecting facilities and routing equipment, SS7 networks are private and logically self-

contained. The private nature of SS7 networks is critical for security and reliability.

SS7 involves two different types of signaling: connection oriented signaling and connectionless

oriented signaling. Connection oriented signaling refers to the establishment of switch-to-switch

facilities call inter-office trunks. These trunks carry carriers of voice communications. The ISDN User

Part (ISUP) part of the SS7 protocol is utilized to establish trunks between switches. In contrast, the

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Transaction Capability Application Part (TCAP) is utilized for connectionless signaling which

typically entails switch-to-database or database-to-database communications. An example of

connectionless signaling is TCAP signaling of HLR to VLR communications discussed in the mobile

networking article.

SS7 Networks: SS7 is comprised of a series of interconnected network elements such as switches, databases, and

routing nodes. Each of these elements is interconnected with links, each of which has a specific

purpose. The routing nodes are the heart of the SS7 network and are called a Signal Transfer Point

(STP). STPs are connected to Service Switching Points (SSP) that are switches equipped with SS7

control logic. SSP switches are connected to the STPs via Access links (A links). STPs also connect to

databases called Service Control Points (SCP) via A links. The SCP is the network element that

contains service control logic such as instructions for converting an 8XX (toll-free) number into a

routable number.

STPs are always deployed in pairs, allowing a spare should one of the STPs have a problem. Each

STP of a "mated pair" are connected to each other via Cross links (C links). STP pairs connect to

other STP pairs via Bridge or Diagonal links (B or D links). B links connect STP pairs that are at the

same level of hierarchy while D links connect STP pairs that are different hierarchical levels. An

example would be STPs in a local network connecting with STPs of a long distance network. Being at

different hierarchies, the local-to-long distance links would be considered D links.

Links used for SS7 communication directly between SSPs (no STP involved) are called fully

associated links (F links). An example of these links is those that are used in combination with voice

trunks between two mobile network SSPs. The F link is used to signal a hand-off message from one

SSP to the other, allowing the mobile phone user to travel from one area (served by one switch) to

another area (served by another switch).

Extended links (E links) are used to connect an SSP to an alternative STP pair. In the event that the

primary STP pair is inoperable, the alternative pair establishes operations with the SSP over the E

links.

Business Issues: In today's modern telecommunications networks, SS7 is used for virtually every call to establish a

voice connection between the callings and called party locations. SS7 is also the medium for

advanced capabilities and applications including mobile networking and services as well as wire line

applications such as toll-free calling and automatic calling card identification

5.8 E1: E1 basics: An E1 link runs over two sets of wires that are normally coaxial cable and the signal itself comprises a

nominal 2.4 volt signal. The signaling data rate is 2.048 Mbps full duplex and provides the full data

rate in both directions. For E1, the signal is split into 32 channels each of 8 bits. These channels have

their own time division multiplexed slots. These are transmitted sequentially and the complete

transmission of the 32 slots makes up a frame. These Time Slots are nominated TS0 to TS31 and they

are allocated to different purposes:

TS0 is used for synchronization, alarms and messages

TS1 - TS 15 used for user data

TS 16 is used for signaling, but it may also carry user data

TS17 - TS31 are used for carrying user data

Time slot 0 is reserved for framing purposes, and alternately transmits a fixed pattern. This allows the

receiver to lock onto the start of each frame and match up each channel in turn. The standards allow

for a full Cyclic Redundancy Check to be performed across all bits transmitted in each frame.

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E1 signaling data is carried on TS16 is reserved for signaling, including control, call setup and

teardown. These are accomplished using standard protocols including Channel Associated Signaling

(CAS) where a set of bits is used to replicate opening and closing the circuit. Tone signaling may also

be used and this is passed through on the voice circuits themselves. More recent systems use Common

Channel Signaling (CCS) such as ISDN or Signaling System 7 (SS7) which sends short encoded

messages containing call information such as the caller ID. Several options are specified in the

original CEPT standard for the physical transmission of data. However an option or standard known

as HDB3 (High-Density Bipolar-3 zeros) is used almost exclusively.

E1 Applications and standards:

The E-carrier standards form part of the overall Synchronous Digital Hierarchy (SDH) scheme. This

allows where groups of E1 circuits, each containing 30 circuits, to be combined to produce higher

capacity. E1 to E5 are defined and they are carriers in increasing multiples of the E1 format. However

in reality only E3 is widely used and this can carry 480 circuits and has an overall capacity of 34.368

Mbps.

Physically E1 is transmitted as 32 timeslots and E3 has 512 timeslots. Unlike Internet data services

which are IP based, E-carrier systems are circuit switched and permanently allocate capacity for a

voice call for its entire duration. This ensures high call quality because the transmission arrives with

the same short delay (Latency) and capacity at all times. Nevertheless it does not allow the same

flexibility and efficiency to be obtained as that of an IP based system.

In view of the different capacities of E1 and E3 links they are used for different applications. E1

circuits are widely used to connect to medium and large companies, to telephone exchanges. They

may also be used to provide links between some exchanges. E3 lines are used where higher capacity

is needed. They are often installed between exchanges, and to provide connectivity between countries.

5.9 Difference in Hub, Switch, Bridge, & Router In an Ethernet network there are 4 devices that from the outside look very similar.

Hubs

Switches

Bridges

Routers

Hub:

A hub is the simplest of these devices. Any data packet coming from one port is sent to all other ports.

It is then up to the receiving computer to decide if the packet is for it. Imagine packets going through

a hub as messages going into a mailing list. The mail is sent out to everyone and it is up to the

receiving party to decide if it is of interest. The biggest problem with hubs is their simplicity. Since

every packet is sent out to every computer on the network, there is a lot of wasted transmission. This

means that the network can easily become bogged down. Hubs are typically used on small networks

where the amount of data going across the network is never very high.

Bridge: A bridge goes one step up on a hub in that it looks at the destination of the packet before sending. If

the destination address is not on the other side of the bridge it will not transmit the data. A bridge

only has one incoming and one outgoing port. To build on the email analogy above, the bridge is

allowed to decide if the message should continue on. It reads the address bob@smith.com and decides

if there is a bob@smith.com on the other side. If there isn’t, the message will not be transmitted.

Bridges are typically used to separate parts of a network that do not need to communicate regularly,

but still need to be connected.

Switch: A switch steps up on a bridge in that it has multiple ports. When a packet comes through a switch it is

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read to determine which computer to send the data to. This leads to increased efficiency in that

packets are not going to computers that do not require them. Now the email analogy has multiple

people able to send email to multiple users. The switch can decide where to send the mail based on

the address. Most large networks use switches rather than hubs to connect computers within the same

subnet.

Router:

A router is similar in a switch in that it forwards packets based on address. But, instead of the MAC

address that a switch uses, a router can use the IP address. This allows the network to go across

different protocols. The most common home use for routers is to share a broadband internet

connection. The router has a public IP address and that address is shared with the network. When data

comes through the router it is forwarded to the correct computer. This comparison to email gets a little

off base. This would be similar to the router being able to receive a packet as email and sending it to

the user as a fax.

Network Patch Panels: Patch panels are most commonly found in Ethernet networks. Cat5e patch panels and Cat 6 patch

panels are the most common but patch panels can be used in many other applications. A patch panel

sometimes referred to as a patch bay or a jack field is a panel designed for the management of cable

connections. On the front side of a patch panel there are jacks designed to receive short patch cables

(RJ45), while on the back of the panel there are either jacks or punch down blocks THAT HAVE

connections of longer and more permanent cables. The assembly of hardware is arranged so that a

number of circuits appear on jacks for monitoring, interconnecting, and testing in a convenient and

flexible way. This offers the convenience of allowing techs to quickly change the circuit of select

signals without the use of expensive dedicated switching equipment. Patch panels are typically rack

mountable.

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6. Alcatel

6.1 LOCATION: Alcatel 1000 El0 is the digital switching system developed by Alcatel CIT. Multi-application, Alcatel

1000 El0 could be used for the entire range of switch, from the smallest local exchanges to the largest

transit gateway switches. It adapts to every type of habitat, from dense urban environment, to sparsely

populated areas, and to every type of climate, from Polar Regions to the hot and humid climates of

Equatorial Africa and the tropics. System operation and maintenance can be local or common to

several switches, or both at the same time.

Alcatel 1000 El0 provides all modern communication services: Basic Telephony, ISDN (Integrated

Services Digital Network), Centrex, digital cellular radiotelephony and all the Intelligent Network

applications. It handles all accepted signaling systems in a current total of over 80 countries and is

built in accordance with recognized international standards. Alcatel CIT actively contributes to

definition of those standards.

SYSTEM APPLICATIONS (NON-EXHAUSTIVE LIST):

• Remote subscribers unit.

• Local subscribers exchange

• Transit exchange (local, trunk or international gateway).

• Hybrid local/transit exchange.

• Tandem exchange.

• Centrex (private or public).

Fig: 1 Alcatel 1000 E10 location in the telephone network

S: Remote line unit

L: Local subscriber exchange

TR: Transit exchange

CID: Outgoing international exchange

CIA: Incoming international exchange

CTI: International transit exchange

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6.2 Block Diagram of Alcatel BWP:

6.3 MAIN CONTROL STATION (SMC):

Location:

The Main Control Station is linked to the following communication media

• The Interstation Multiplex (MIS): it carries out interchanges of information with the other Main

Control Stations (SMC) and with the SMM station,

• The Main Control Station Access Multiplexes (MAS): 1 to 4 they carry out interchanges of

information with the Auxiliary Equipment Control (SMA), Trunk Control Station (SMT) and

Matrix Control Station (SMX) connected on those multiplexes

• The Alarm Multiplex (MAL): this transmits power alarms from the station to the SMM station.

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Role (Function) of SMC: The Main Control Station (SMC) supports the following functions

• MR (Call handler): call processing,

• CC (Communication Control): processing of the SSP application,

• TR (Translator): database,

• TX (Charging): charging for communications,

• MQ (Message Distributor): message distribution,

• GX (Matrix System Handler): management of connections,

• GS (Services management): SSP application,

• PC (SS7 Controller): signaling network management.

According to the configuration and the traffic to be handled, one or more of these functions may be

supported by the same Main Control Station

Functional Architecture:

General architecture of a multiprocessor station

• Philosophy of multiprocessor derived from Alcatel 8300 system concepts one or more than one

processor, one or more than one intelligent coupler, interconnected by a bus and interchanging

data through a common memory.

• Two-way communication between subassemblies coordinated by the basic system.

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BSM = Multiprocessor Station Bus

A multiprocessor station can include:

• one or more than one multiplex coupler,

• one or more than one processor unit,

• a common memory,

• Specific couplers for switching functions or data processing inputs/outputs.

SMC Architecture:

The Main Control Station includes:

• a main multiplex coupler (CMP),

• a main processor unit (PUP),

• a common memory (MC),

• 1 to 4 secondary processor units (PUS),

• 1 to 4 secondary multiplex couplers (CMS).

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Physical Form of SMC:

The Main Control Station (SMC) is organized around a standardized Multiprocessor Station Bus

(BSM). The size of this bus is 16 bits.

The different boards are connected to this bus and it is used by them as a means of communication.

Thirteen boards can be connected onto the Multiprocessor Station Bus within a Main Control Station:

• an ACAJA board is responsible with its associated ACAJB to manage interchanges between the

Interstation Multiplex (MIS), and the BSM,

• four ACAJA are responsible with their associated ACAJB boards to manage interchanges

between the MAS and the BSM,

• three ACMCQ boards which carry out the Common Memory function, or only one ACMCS(1)

• an ACUTR board which carries out the Main Processor function (PUP),

• four ACUTR boards which carry out the Secondary Processor functions

• (PUS),

The ACALA board, which is not connected on Multiprocessor Station Bus, is responsible for

collecting and transmitting power alarms of the Main Control Station. It is connected to the Alarm

Multiplex (MAL).

• 5 types of cards:

UC 68020 or 68030 ACUTR

16 MB memory ACMCQ

MIS/MAS coupling module ACAJA/ACAJB

Alarms coupling module ACALA

• SMC station (max. 17 cards + 2 converters).

• Estimated maximum consummation at 5V < 160W

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Location Assembly:

6.4 Auxiliary Equipment Control Station (SMA):

Role of SMA:

The Auxiliary Equipment Control Station (auxiliaries’ multiprocessor station) supports the following

functions:

• ETA: Auxiliary Equipment Manager: Management of tone and of auxiliary equipments,

• PUPE: SS7 Protocol Handler: Processing of CCITT No. 7 Protocols.

According to the configuration and the traffic to be handled, one SMA can support an auxiliary

equipment manager software machine (ETA), a SS7 Protocol Handler Software Machine (PUPE), or

both.

The auxiliary equipment control station contains auxiliaries of the OCB 283 exchange. These are:

• Frequency receivers/generators,

• Conference circuits,

• Tone generators,

• Clock management,

• CCITT No. 7 signaling receivers/transmitters.

Location of SMA: The Auxiliary Equipment Control Station is linked to:

• The connection network by a set of 8 matrix links. It is via the connection system that the

auxiliary equipment control station receives basic time distributions from the STS,

• The Main Control Station Access Multiplex (MAS). It carries out interchanges of information

between the auxiliary equipment control station and the command components of the OCB

283,

• Alarms Multiplex (MAL).

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Functional Architecture:

The Auxiliary Equipment Control Station is connected to the Host Switching Matrix by 8 matrix links

equipment:

The SMA may have the following boards:

• A main multiplex coupler (CMP),

• According to call-handling capacity power necessary:

A main processor unit (PUP),

A secondary processor unit (PUS),

A common memory (MC),

• 1 to 12 couplers:

Processing of speech signals (CTSV),

Multiprotocol signaling (CSMP),

Clock management (CLOCK)

The CTSV can process functions of the following types:

• Frequency receiving generation,

• Conference,

• Tone generation,

• Testing of sundry modulations, psophometer.

The CSMP can process protocols such as No. 7 signaling or other HDLC protocols.

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Physical Form of SMA: The Auxiliary Equipment Control Station is organized around a standardized Multiprocessor Station

Bus (BSM). This is a 16-bit bus. The different boards are connected to this bus, which is used by them

as a means of communication. Sixteen boards can be connected to the multiprocessor station bus:

• an ACAJA board is responsible with associated ACAJB board to manage interchanges via the

Main Control Station Access Multiplex (MAS),

• an ACMCQ or ACMCS board which supports the bulk memory of the station,

• an ACUTR board: main processor function (PUP),

• an ACUTR board which carries out the secondary processor functions (PUS),

• At most 12 boards which carry out the specific operations for which the. Auxiliary Equipment

Control Station is responsible:

o one or more ICTSH board,

o one or more ACHIL board,

o An ICHOR board.

The following are inserted within the station but not connected to the multiprocessor station bus:

• A pair of ICID boards. These are the SAB interface between the branches of the connection

matrix and the auxiliary equipment control station,

• An ACALA board which is responsible for collecting and transmitting alarms appearing on

auxiliary equipment control station.

The structure chosen has the advantage of permitting a wide variety of configurations or, at the same

time, call-handling capacities (put into physical form by the number of ACUTR). The operational

capacity (according to the number and the type of application boards) can be adjusted to a wide

variety of needs.

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9 types of boards

CMP coupler ACAJA/ACAJB

Main processing unit, secondary processing unit ACUTR

Common memory ACMCS

Speech signal processing coupler ICTSH

Clock coupler ICHOR

Alarms coupler ACALA

Branch section function ICID

Multiprotocol processing coupler ACHIL

Auxiliary Equipment Control Station: (maximum of 20 boards + 2 CV)

Maximum consumption on 5V < 120 W

Functions of ICTSH Board:

ICTSH BOARD:

• It can generate 32 voice frequency signals/timings e.g. Ring tone, Busy tone etc. Signals are

sequences of mono, bi, tri or quadric frequencies. A sequence consists of maximum eight

“transmission/silence” sequences.

• Can manage 8 RGF terminals.

• Can provide 8 conf. Circuits 4 subs on each.

• Supervise the process of recorded announcements.

Functions of MLETA: 1) Call processing:

• Reception of frequency dialing

• Transmission of frequencies according to instructions.

• Management of ICTSH boards

• Provision of conf. Circuits.

• Provision of tones

• Indication of call waiting.

2) Observations (load of ICTSH resources)

3) Clock Management

4) Maintenance

• LA continuity check

• To check the modulation of announcements.

• On line test of ICTSH & ICHOR board.

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Location and Rack Assembly:

6.5 TRUNK CONTROL STATION (SMT):

Role of SMT:

� It provides functional interface between PCM & the switching centre. These PCM come from:-

� Other switching centers.

� A Remote subscriber Digital Access Unit (CSND).

� A Remote Electronic Satellite concentrator (CSED).

� The digital recorded announcement equipment.

� To control the PCM, MLURM is implemented on SMT which performs:

I. In PCM to switching centre direction:

� HDB-3 conversion to binary

� Extraction of CAS signaling.

� Management of C7 signaling.

� Cross-connection of channels between POCM & LR

II. In Switching centre to PCM direction:

� Binary to HDB-3 conversion

� Transmission (injection) of CAS in T.S. 16

� Management of C7 signaling.

� Cross connection of channels between LR & PCM.

Location of SMT:

The Trunk Control Station is connected to:-

� CSND, CSED, digital announcement equipment & other switching centers by max. 32 PCM.

� SMX through up to 32 LR (4GLR)

MAS is used to communicate with other stations

� Stations alarm ring (MA2).

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General Architecture:

• 32 PCM are divided in 8 groups of 4 PCM each.

• Each group of 4 PCM is processed by a software module MRM (multiplex connection

module) or MRS (Satellite connection Module)

• All these eight modules are managed by logic: (LOGUR-0 or LOGUR-1) which is the pilot

logic.

Physical Form of SMT:

� 2 Sub-racks for 1 complete SMT.

� 12 types of boards.

o Main Multiplex coupler ACAJ A, ACAJ B.

o 6 types of board for PCM controller ICPRO, ICD1M, ICMEC, ICCTM, ICSDT,

ICCLA.

o Acquisition logic ICMOD.

o PCM termination ICTR1

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o Alarm Coupler ACALA

o Branch selection function ICID

� Maximum outfitting 49 boards + 4 converters.

Location and Rack Assembly:

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7. TRANSMISSION:

Transmission is the action of conveying signals from one point to one or more other points while

media describes the cabling and various media used to send data b/w multiple points of a network.

Transmission media is the physical path between transmitter and receiver.

7.1 Types of transmission Media:

7.2 Guided media:

• Conductive metal

Twisted pairs, coaxial cable

• Glass or plastic

Fiber optics

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Electromagnetic spectrum:

The above picture shows the EM spectrum and indicates the frequencies at which various guided

media and transmission technique operate.

a. Twisted pairs:

Since straight copper wires tend to act as antennas and pick up extraneous signal. The

twisting help reduce the amount of outside interferences. Twisted pairs often are bundled together and

wrapped in a protective coating. Each pair has twist length, reducing the interference b/w them

(crosstalk).

b. UTP:

UTP is a primary choice for a 10 Base T and 100BaseT Ethernet network that use UTP cabling at 10

Mbps and 100Mbps respectively. B/c is lacks shielding, UTP is not good at blocking noise and

interference as STP.

c. STP:

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STP can handle high speed transmissions. Cable itself is relatively expensive, can be quite bulky and

heavy. STP is used in ARC net and token ring networks.

d. Coaxial cable:

Coaxial cable is a popular for cable television transmission and for creating LAN such as Base

Operates at 10Mbps.

RG-6: Drop cable for CATV, 75 ohm impedance

RG-8: Thick Ethernet LAN (10 Base 5), 50 ohm

RG-11: Main CATV truck, 75 ohm impedance

RG-58: Thin Ethernet LAN (10 Base 2), 50 ohm

RG-59: ARC net, 75 ohm

e. Optical fiber: Fiber optic cable or optical fiber provides a medium for signals using light rather than electricity.

Light waves are immune to EM interference and crosstalk. Optical fiber can be used for much longer

distance before the signal must be amplified. Data Transmission using optical fiber is many faster

than electrical methods.

7.3 Wireless (Unguided Media) Transmission:

• Microwave, satellite, Radio

a. Microwave:

Microwave links are widely used to provide communication links when it is impractical or too

expensive to install physical transmission media. Two properties of microwave transmission place

restriction on its use. 1st microwave travels in straight line and will not follow the earth curvature. 2

nd

atmosphere conditions and solid objects interfere with microwaves. For example, they cannot travel

through buildings. Typical microwave distances before repeaters are necessary:

Frequency (GHz) Approx. distance (miles)

2-6 30

10-12 20

18 7

23 5

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SRAL:

Microwave systems cover most of connectivity needs especially in the lower layers of the

transmission networks, consolidating their role of reliable, easy-to-install and cost-effective access

solution. Siemens, used to be one of the frontrunners in this market segment, is ready to match the

expectations of the new incoming telecommunication era characterized by broadband and mobility

convergence.

Nowadays, the new challenge launched by operator’s aims to increase link density and capacity,

leaving spectrum occupancy practically unchanged. Siemens, always ready to acknowledge market

indications and trends, adds to its extensive microwave portfolio the new line of point to point low

capacity digital radio: SRAL XD.

Siemens expertise covers most of the outstanding technologies which current applications are based

on: switching, cellular technology, radio and networking, voice and data over IP and ATM.

An outstanding turnkey project management capability, the ownership of a so wide range of in-house

product lines and a worldwide field proven experience, represent the unequaled Siemens business

card.

Units:

SRAL has two units IDU (indoor Unit) and ODU (outdoor Unit). There functions are

IDU Basic Functions:

ODU Basic Functions:

System interface to external world Modulation of baseband signal

Baseband digital signal processing Up-conversion to RF signal

IDU-ODU cable interface management Down-conversion of received RF signal

System supervision and configuration Mngt. Demodulation to baseband signal

Equipment power supply ODU supervision and config. Mngt

IDU-ODU cable interface Mngt

Applications:

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SRAL XD line is primarily designed four ban networks, but is also suitable in regional networks

meeting all the requirements of access and trunk applications.

• Mobile Networks: in the 3G Mobile ATM based network, typically SRAL XD is used to collect

traffic conveying from Node B to Hub stations; in the 2G networks it is already implemented to

provide access to core networks. In the next future, the overlay of the two mobile networks will

certainly benefit from SRAL XD upgrading facilities, rewarding operators with flexible and versatile

infrastructures.

• Mobile Networks: in the 3G Mobile ATM based network, typically SRAL XD is used to collect

traffic conveying from Node B to Hub stations; in the2G networks it is already implemented to

provide access to core networks. In the next future, the overlay of the two mobile networks will

certainly benefit from SRAL XD upgrading facilities, rewarding operators with flexible and versatile

infrastructures.

• Fixed services Networks: SRAL XD supports ATM/IP networks, LAN and WAN.

a. Satellite:

Satellite transmission is microwave transmission in which one of the stations is a satellite orbiting the

earth. A microwave beam is transmitted to the satellite from the ground. This beam is received and

retransmitted to predetermined destination. Receiver and transmitter are known as transponder.

The optimum frequency range for satellite is the range 1 to 10 GHz. Below 1GHz, there is significant

noise from natural sources, atmospheric noise, and noise from electronic devices. Above 10 GHZ, the

signal is attenuated by atmospheric absorption.

Satellite bands:

Freq. Bands Uplink Downlink Use

4/6 C 5.925-6.425 3.7-4.2 Commercial

7/8 X 7.9-8.4 7.9-8.4 Military

11/14 Ku 14-14.5 11.7-12.2 Commercial

20/30 Ka 27.5-30.5 17.7-21.2 Military

20/44 Q 43.5-45.5 20.2-21.32 Military

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b. Radio:

A radio transmitter is placed at the fixed wired terminal point, providing a wireless link b/w each

terminal and central site. The coverage area of a base station is restricted by limiting its power o/p so

that it provides only sufficient channels to support the total load in that area. Wider coverage area is

achieved by arraying multiple base stations in a cell structure.

Each base station operates using different band of frequencies from its neighbors. Since the field of

coverage of each base station is limited, it is possible to reuse its frequency band in other parts of

network.

DRS (Digital Radio system):

Digital radio system is used to provide telecommunication, connection b /w destination point of

exchanges, sources and drops, nodes and terminating points of the PTCL network point to point

transport of voice and data. In order commission and links the expansion of local telephone exchange

system detailed engineering studies is made to determine the requirements of the transmission media

keeping in view the existing system. Up gradation of the existing DRS links is too made for the

replacement with high capacity links.

Transmission developing work:

• Establishment of new Digital Radio Links to connect new exchanges.

• Up-gradation of Digital Radio Links for enhanced requirement.

• Towers at new exchanges / repeaters for DRS links.

• Power plant including rectifiers, batteries, solar modules and diesel engine generators.

• Construction of building for repeater stations.

Equipment Architectures:

• Indoor unit (ODU)

• Coaxial cable

• Outdoor unit (ODU)

• Antenna

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7.4 Factors to select media Cost

Data rate/ bandwidth

Distance

Twisted pairs Coaxial Optical fiber Microwave

Data rate

(Mbps)

1-100 10 400-500 200-300

Interference Electrical Electrical Immune Solid object

Distance( miles) Up to 1 2-3 20-30 20-30

8. References: • Supervisors at Central exchange Bahawalpur

• www.google.com.pk

• www.wikipedia.com

• www.ptcl.com.pk