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Copper Access Network

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INTRODUCTION TO TELECOMMUNICATION NETWORK

WHAT IS TELECOMMUNICATIONS?

To be able to communicate at long distance through electrical or optical signals.

OR

A long distance communication via integration of information sharing networks all tied together.

TELECOMMUNICATION NET WORK

A set of nodes and links that provides connections b/w two or more defined points to carry out exchange of information b/w them

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Public Switched Telephone Network (PSTN)

PSTN is the combination of:

Terminal Equipments

Access Network

Switching Network

Transmission Network

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Terminal Equipments

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Access Network

(Connectivity of Subscriber with Exchange)

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• Local exchange • Remote subscriber switch • Tandem exchange. • Transit exchange. • International gateway exchange.

TYPES OF EXCHANGES

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Call example in PSTN Following steps are involved in the establishment and

subsequent release of a call on PSTN:

1. DETECTION OF HOOK OFF

2. PROVISION OF DIAL TONE

3. DIALING OF DIGITS

4. RESERVATION OF RESOURCES FOR CALL

5. RINGING OF CALLED PARTY AND RING BACK TO CALLING

PARTY

6. DETECTION OF ANSWER FROM CALLED PARTY

7. NECESSARY CHARGING INITIATION

8. SPEECH

9. INITIATION OF CALL TERMINATION FROM EITHER END

10. CALL END, RELEASE OF ALL RESERVED RESOURCES

11. NECESSARY ACTION REGARDING BILLING

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1 Off Hook

2 Dial Tone

3 Digits Dial

4 Siezure 5a Ringing

5b Ring Back

6 Off Hook

7 Charging Started 8 Conversation / Speech

9 Call End

10 Release Resources 10 Release Resources 10 Release Resources

11 Charging Stopped

GENERAL CALL SETUP

Local Exchange

Local Exchange A B

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PSTN- A typical Network

LE LE

NT

IGW

NT

LT

LE LE

IGW

LT

TRUNK

ACCESS NETWORK ACCESS NETWORK ACCESS NETWORK ACCESS NETWORK

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Access Network

LE END USER

EX

EX

AN is called “the last mile of Telecom Network”

Access Network

INTRODUCTION TO ACCESS NETWORK

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Components and Structure of Access Network

MDF

user

Connection

Cabinet

Distribution

Box(DP)

Primary cable

Copper Cables Based

Secondary cable Drop Wire

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COMPONENTS OF ACCESS NETWORK

MDF:- MDF stands for Main Distribution Frame. It is an

interface or test point between a telephone exchange

and subscriber local loop. There are Two sides,

horizontal and vertical side.

Horizontal Side: For Exchange Side

Vertical Side: For External Cable

Horizontal and Vertical sides connected via jumper wire.

Cabinet: Terminating Box where primary and Secondary

cables are terminated.

DP: Stands for Distribution point, Secondary cable

distributes at DP .

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COMPONENTS OF ACCESS NETWORK

Primary Cable: From MDF to Cabinet

Secondary Cable: From Cabinet to DP

Drop wire: From DP to Subscriber premises.

Rosette is a connector that use to connect the

telephone wire with an output of RJ 11

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Role of AN in the Operator’s Business

• Final tool for service delivery to the end users

Quality & flexibility of AN determine the speed and quality of service to the end users

• Major cost factor for the operator

Accounts for about 40~50% of total telecom network investment

• Very important in a competitive environment

End user oriented, generates revenue for operators

Services

node Access Network

End user

Services

Motive: revenue

Good AN, Better Services, More Revenue !

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CABLES, TYPES OF CABLES &

COLOUR SCHEME

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COPPER CABLE

Definition:

It is collection of insulated conductors

arranged in particular color scheme in

a single core and covered with several

protective layers.

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KINDS OF CABLE

1. AERIAL CABLE

2. UNDERGROUND CABLE

3. SUBMARINE CABLE

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KINDS OF UNDER GROUND COPPER CABLE

1. COAXIAL CABLE.

2. OPTICAL FIBRE CABLE.

3. POLYETHELENE (PE) CABLE.

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CONSTRUCTION OF P.E CABLE

1. ARMOURED 2. UNARMOURED

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21

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FOUR IMPORTANT PART OF COPPER CABLE

1. CONDUCTOR

2. INSULATION

3. PROTECTIVE LAYER

4. COLOUR SCHEME

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CONDUCTOR

Any material that easily permits the flow of

electric current.

For example: Copper, Silver and Aluminum etc.

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INSULATION

Any material that does not permit the flow of

electric current.

For example: Plastic, Paper and Glass etc.

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PROTECTIVE LAYERS.

PROTECT THE CABLE FROM

MECHANICAL DAMAGES

MAGNETIC EFFECTS

ELECTRICAL INTERFERENCE

ENVIRONMENTAL EFFECTS

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COLOR SCHEME OF P.E CABLE.

25 PAIR COLOR SCHEME IN ONE GROUP

A- WIRE B-WIRE

1. WHITE BLUE

2. WHITE ORANGE

3. WHITE GREEN

4. WHITE BROWN

5. WHITE GRAY

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COLOR SCHEME OF P.E CABLE.

25 PAIR COLOR SCHEME IN ONE GROUP

A- WIRE B-WIRE

6. RED BLUE

7. RED ORANGE

8. RED GREEN

9. RED BROWN

10. RED GRAY

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COLOR SCHEME OF P.E CABLE

25 PAIR COLOR SCHEME IN ONE GROUP

A- WIRE B-WIRE

11. BLACK BLUE

12. BLACK ORANGE

13. BLACK GREEN

14. BLACK BROWN

15. BLACK GRAY

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COLOR SCHEME OF P.E CABLE

25 PAIR COLOR SCHEME IN ONE GROUP

A- WIRE B-WIRE

16. YELLOW BLUE

17. YELLOW ORANGE

18. YELLOW GREEN

19. YELLOW BROWN

20. YELLOW GRAY

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COLOR SCHEME OF P.E CABLE

25 PAIR COLOR SCHEME IN ONE GROUP

A- WIRE B-WIRE

21. VIOLET BLUE

22. VIOLET ORANGE

23. VIOLET GREEN.

24. VIOLET BROWN.

25. VIOLET GRAY.

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1. GROUP is of 25 pairs

2. UNIT is of 50 pairs

3. SUPER UNIT is of 100 pairs

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PRIMARY CABLE

The cable laid from MDF to cabinet is called

primary cable.

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CAPACITY OF PRIMARY CABLE

1. 200 pair.

2. 300 pair.

3. 400 pair. not used in Pakistan.

4. 600 pair.

5. 900 pair.

6. 1200 pair.

7. 1500 pair.

8. 1800 pair.

9. 2400 pair. not used in Pakistan.

10. 3200 pair. not used in Pakistan

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SECONDARY CABLE.

The cable laid between cabinet to D.P is

called secondary cable.

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CAPACITY OF SECONDARY CABLE

1. 10 pair.

2. 20 pair.

3. 30 pair.

4. 50 pair.

5. 100 pair.

6. 200 pair.

7. 300 pair.

8. 400 pair. Not used in Pakistan.

9. 600 pair.

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MDF, Cabinet, DP, Cable

Terminations & Record

Keeping

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Terminations

There are five positions of termination in the

Access Network

Main Distribution Frame (MDF)

Cross Connection Cabinets (CCC)

Distribution Point (DP)

Terminating Box

Rossette / Socket

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The major connection frame in a telephone exchange

on which the local cable pairs and exchange cable

are terminated.

Here any cable pair can be cross-connected to any

exchange cable (number)

MDF Types

– Floor type

– Wall type

Main Distribution Frame (M.D.F)

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Main Distribution Frame (M.D.F)

The M.D.F. must be installed in a separate

room nearest to the switch room

The frame must be supported with proper

nuts and bolts for disconnection strips and

fuse strips.

The M.D.F must be supported by the wall

brackets.

The M.D.F must be properly earthed.

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Types of Wiring on M.D.F.

On mini strips the under ground installation cable is terminated on left/front side of M.D.F

Switch board cable from exchange side is terminated on right/rear side of the M.D.F

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MDF JUMPERING

The jumper wires of 0.4 mm dia must be used

for jumpering.

The jumper wires must be used through

guide clamps

The underground cables/jumpers terminated

on the mini strips must be punched properly

using punching tool.

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MINI STRIP

Mini strip consists upon 100 pairs and

counted from left side because cable side is

also on left side and right side is exchange

side .

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TERMINATION OF JUNCTION CABLES

Cables connecting any two exchanges are called

junction cables.

Extreme ends of junction cables are terminated on

MDF’s (Main Distribution Frames) of each exchange.

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TERMINATION OF PRIMARY CABLES

Primary cables connect MDF of an exchange to CCC’s (Cross Connection Cabinets) installed at suitable points of feeding areas.

Starting end of the cable (generally called NEAR END) is terminated on the MDF and remote end (called FAR END) is terminated on CCC (Cross Connection Cabinets) terminal blocks.

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Main Distribution Frame (MDF)

MDF is a junction of switching system and

outside plant.

The cables coming from switches are

terminated on horizontal tag blocks mounted

on one side of the MDF.

Cables coming from outside are terminated on

vertical side terminal blocks/strips.

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MDF (Cont..)

Horizontal side of the MDF is called switching

side and the vertical side is called

“Geographical side”.

Any switching side pair can be connected to

any pair of outside cable through jumper

wire.

100 pair mini strip is used on MDF.

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MDF (Cont..)

A vertical row (Bay) can accommodate 800

pair termination of network cable.

The network cables are terminated on the left

side of the strip and right side is used for

jumping.

These strips also provides measuring &

testing facility for network cables.

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TERMINATION OF SECONDARY CABLES

Secondary cables connect the CCC (Cross

Connection Cabinets) to DPs (Distribution Points)

may be pole mounted DPs or wall mounted indoor

DPs or pillar type DPs.

Starting end generally called near end) of secondary

cables is terminated on terminating blocks of CCC

and the remote ends (called Far Ends) of secondary

cables are terminated on 10 pair terminal blocks of

any kind of DPs.

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CROSS CONNECT CABINET

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CROSS CONNECTION CABINET (CCC)

It is a component of the Out Side Plant installed at the junction of Primary and Secondary cables

Standard size CCC can accommodate termination of 1200 pairs.

Some of the cabinet designs are double sided and cables can also be terminated on the other side of the cabinet. It doubles its termination capacity

Usually the ratio of 5:7 is maintained between primary cables & secondary cable pairs.

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CROSS CONNECTION CABINET (CCC) (Cont..)

The cabinet is installed on a pre-cast RCC base.

Minimum height of the base plate of the cabinet shall

be 30 cm above the ground/road level (whichever is

higher).

The doors shall be water tight and the location of the

cabinet shall be such that it does not block the traffic

or pedestrians.

Sufficient working space ( 1m minimum) shall be

available on the back side of the cabinet.

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Space Distribution Plan Of Primary & Secondary Termination

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Record Keeping of Cabinet

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DISTRIBUTION POINT

There are three types of DPs in use by the PTCL.

i) Pole Mounted DPs (External DPs)

ii) Wall mounted (Internal DPs

iii) Piller type DPs

The capacity of DP is generally 10 pairs. In case load is

concentrated (office buildings etc.) the termination capacity can

be increased up to 20, 30 or even 50 pairs in case of internal

DPs.

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DISTRIBUTION POINT. D.P

DEFINITION

D.P means distribution point. It is

fixed on A4BC post. It is the last point in the

local cable network from where subscriber line

(loop) is extending to subscriber premises.

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DISTRIBUTION POINT. D.P

CONSTRUCTION.

The D.P consists of

1. Housing/ body.

2. Terminal block

3. Cover

4. Earth Terminal.

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DISTRIBUTION POINT. D.P

TYPE OF D.P.

There are three type of D.P.

1. Pole type D.P.

2. Wall type D.P.

3. Pillar type D.P.

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POLE TYPE D.P

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POLE TYPE D.P

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DISTRIBUTION POINT. D.P

WALL TYPE D.P.

10 pair D.P. box is installed with wall at about 8 feet high from the ground level Underground cable 10 pair runs through the 10 feet. G.I. pipe 1” dia up to C.T. Box 8 feet out land two feet in the ground. G.I. pipe is clipped with wall at three places from internal D.P.

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.WALL TYPE D.P

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POLE/

WALL TYPE D.P

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POLE/ WALL TYPE D.P

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DISTRIBUTION POINT. D.P

PILLAR TYPE D.P.

This is a special D.P used in Islamabad.

Underground cable is terminated on 10 pair

C.T. box

fixed at top in the D.P on back side.

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PILLAR TYPE D.P

PILLAR TYPE D.P.

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Record Keeping of DP

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DP Post, Post Types & Accessories,

Drop wire & SSA Cable Accessories

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POLES

DEFINITION:

THE POST OR POLES USED TO SUPPORT

FOR OVER HEAD LINES.

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POST

TYPE OF POST:

1. Tubular Post.

2. Rail Post.

3. Wooden Post.

4. Coupled Post.

5. Concrete Post.

6. Bridger fixture Post.

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POST

TUBULAR POST.

These Post consist of Tubes made of steel

sheets fitted together to give a post of the height

and strength required.

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POST

ADVANTAGES OF TUBULAR POST.

1. It is light and strong.

2. Easy for transportation.

3. Easy in fitting and dismantling.

4. Damaged parts can be easily changed.

5. Any type of post in length and strength can be

made according to our requirements.

6. It is durable being made of steel with

galvanized surface.

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POST

TYPES OF TUBES & SIZES.

8 feet. T Tube

8 feet. A Tube

8 feet. B Tube

8 feet. C Tube

8 feet. D Tube

8 feet. E Tube

8 feet. F Tube

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POST

4 feet. A 4 Tube.

4 feet. B 4 Tube.

4 feet. C 4 Tube.

5. TYPES OF TUBES & SIZES OF TUBES & SIZESTYPES

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POST

D.P POST (A4BC) & ITS PARTS.

Five parts are there in D.P / A4BC Post.

1. Lightening Spike.

2. Cap.

3. A4BC Tube.

4. Socket.

5. Sole plate.

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D.P BOX

CAP

A4 TUBE

B-TUBE

SOLE PLATE

SOCKET

D.P BOX

G.I. PIPE

VENT HOLE

C-TUBE STAINLESS STEEL BAND

LIGHTING SPIKE

G.I. PIPE

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DROPWIRE

DEFINITION

Drop wire is a self-supporting aerial cable

capable of sustaining the span load and

wind pressure and greatly resistive to

climate and environmental effects.

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DROPWIRE

USES.

It is used for extending exchange loop to

subscriber’s premises and erected from

distribution point (D.P) to subscriber’s office.

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DROPWIRE

CONSTRUCTION.

Its construction is simple. It contains two

wires of hard drawn cadmium wire, bronze

wire or copper weld wire.

copper weld wire is more common in use.

The wire are enclosed in a jacket-cum

insulation of polyethylene.

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DROPWIRE

STANDARDS.

Roll length 500 meters

Roll Weights 15 KG

Attenuation loss 0.87 db / Km

Dip 1 Cm/ Meter

Headway on main road 20 feet

Headway on branch road 16 feet

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DROPWIRE

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DROPWIRE

ADVANTAGES OF DROPWIRE.

1. Easy to erect.

2. Takes less times in erection.

3. Less labour is required.

4. Used to provide emergency circuits.

5. Can be used on electric posts, trees and wall

,etc.

6. Less exposed to faults due to contacts, kite

strings, vegitation etc.

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DROPWIRE

7. Strongly resistive to climatic and weather effects.

8. Costly fittings are not required like

insulator, bracket etc.

9. Working connection are not interrupted when

new drop wires are being erected.

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DROP WIRE ACCESSORIES.

ROSETTE.

It is provide in between ceiling rose and

subscriber’s instrument it links instrument with

line card.

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DROP WIRE ACCESSORIES

G.I PIPE.

It used on distribution post and band with the

help of stainless steel band and seal to protect

cable from damage at D.P. (Its usual length will

be 10 feet).

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DROPWIRE

GENERAL INSTRUCTION FOR DROPWIRE.

1. The length of the Drop wire section should be

kept as short as possible.

2. Crossing of main road highway as well as

railway by Drop wire should be avoided.

3. The Drop wire should be suspended properly in

any case as per specification.

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DROPWIRE

4. Loose placing of Drop wire on balconies, roofs,

etc. should be avoided. The standard span of

Drop wire should be kept 50 meters and in

exceptional case it can be up to 70 meters.

5. The Parallel installation of more than three Drop

wire should be avoided. For more than three

lines in parallel it is better to used self

supporting aerial cable

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DROPWIRE JOINTING

Drop wire joints have to

be avoided.

Only one joint shall be

allowed in one span.

Not more than two joints

in a complete drop wire

service line are allowed.

.

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SELF SUPPORT AERIAL CABLE

DEFINITION.

An aerial cable whose conductors as well

as the guard wire are closed in one jacket and

can be suspended directly on the support.

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AERIAL CABLE

CONSTRUCTION

Aerial cable consist of

Annealed copper twisted wire.

Polyethelene insulation.

Plastic paper.

Aluminium foil.

Earth wire.

Polyethelene sheath-cum-jacket.

Guard wire.

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SURVEYING OF AERIAL CABLE

1. Choose the short route.

2. The strength, height and spacing of poles must

carefully be planned.

3. The proposed route must be surveyed.

4. Cable type and size should be selected.

5. Stay arrangement must be worked out.

6. Keep distance from electric wire .

7. The provision period for aerial cable is 7 years.

At the end of provision period the cable should

be relieved rather than replaced.

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Subscriber Office Installation

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Subscriber Office Installation

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Connectors

Connector types:

R J - 11

R J - 45

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Cables

Cable types

STP & UTP

Coaxial

Ethernet

Optical Fiber

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JOINTING OF UNDERGROUND CABLE

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CROSS SECTION OF UNDERGROUND CABLE

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CABLE CONSTRUCTION

CABLE CONSTRUCTION CONDUCTOR

Fully annealed high quality solid copper , the conductor sizes are 0.4, 0.5, 0.6 & 0.9 mm.

INSULATION

Color High Molecular Weight Solid High Density Polyethylene.

COLOUR CODING

Cables are fully color coded in accordance with PIC even count color code.

PAIRING

Two colored insulated conductors are uniformly twisted together to form a pair. Varying lay length is designed to minimize the cross talk and capacitance unbalance.

STRANDING / CABLING

Twisted pairs are assembled into unit of 10, 20, 25, 50 or 100 pairs. When desired for lay-up reason, the units are divided into two or more sub-units, which are bind with durably colored Polyethylene Tapes to form a compact and circular cable core.

FILLING COMPOUND

The water resistant filling compound is applied to fill the air spaces within the cable core

CORE COVERING

A non-hygroscopic and dielectric Polyester Tape and Water Blocking Tape are applied helically having a suitable overlap.

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FLOODING COMPOUND

Sufficient flooding compound is applied between the core wrap and shield.

MOISTURE BARRIER INNER SHEATH

An Aluminum Tape with Co-polymer coating is applied over the cable core and sheath with Black Polyethylene Compound.

ARMOUR (OPTIONAL)

A Tin Coated Steel Corrugated Tape is applied longitudinally directly over the Inner Sheath with suitable flooding compound.

JACKET

Black High Molecular Weight Low Density Polyethylene Compound.

IDENTIFICATION

An identification Tape durable marked with the manufacturer’s name, year of manufacturing and cable size, if required, is placed under the Core Covering Tape. Alternatively, these details may be printed on the outer jacket of cable with length marking.

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Cable Faults and Localization, Testing Equipment, Test parameters

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TYPES OF MAINTENANCE

Preventive maintenance, is conducted to keep

equipment working and/or extend the life of the

equipment.

Corrective maintenance, sometimes called

"Repair", is conducted to get equipment working

again.

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TESTING POINT OF ACCESS NETWORK

There are five testing points in Copper Access Network for fault localization:

1. Main Distribution Frame (MDF)

2. Divisional Cabinet / Cross Connection Cabinet

3. Distribution Point (DP)

4. Termination Box

5. Rossette / Socket

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INSULATION RESISTANCE

Definition:

Insulation resistance is the resistance of the

insulation, which separates the conductors.

It is the total resistance of all the leakage path

throughout the cable.

Insulation resistance is inversely proportional to

length of the cable. i.e. Insulation resistance

decrease with the increases in length of cable.

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INSULATION RESISTANCE (cont’d)

The low Insulation Resistance causes.

(a) Electricity Leakage in the Line,

(b) Heavy Loss of Energy,

(c) Weaken Signals.

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INSULATION RESISTANCE (cont’d)

Unit of Insulation Resistance:

Insulation resistance is measured in

Mega ohm and expressed as

Mega Ohm / km (MΩ / km)

one mega ohm =1,000,000 ohms

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INSULATION RESISTANCE (cont’d)

Standard Insulation Resistances are.

PE CABLE 10,000 mega ohm/km

DROP WIRE 10,000 mega ohm/km

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INSULATION RESISTANCE (cont’d)

Equipment used for measuring insulation resistance:

1. Meggar 100V DC – 100 M ohm

500V DC – 500 M ohm

500V DC – 1000 M ohm

2. Insulation Tester.

3. Meggar ohm meter.

4. Digital Meggar.

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DC LOOP RESISTANCE

• Telephone line consist of two wire (a & b wire)

• DC loop resistance is the total resistance of

telephone line conductors.

DC Loop Resistance = Resistance of A & B wire.

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DC LOOP RESISTANCE (cont’d)

o It is expressed as ohm / km.

o Its value mainly depends on the diameter of

conductor of the cable.

o DC loop resistance decrease by the increase in

diameter of conductor.

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DC LOOP RESISTANCE (cont’d)

Standards of DC Loop Resistance of PE Copper

Cable:

• 0.4 mm conductor diameter 290 ohm/km.

• 0.5 mm conductor diameter 184 ohm/km.

• 0.6 mm conductor diameter 126 ohm/km.

• 0.7 mm conductor diameter 92 ohm/km.

For Drop-wire

• 1.0 mm conductor diameter 144 ohm/km.

113

DC LOOP RESISTANCE (cont’d)

Equipment used for measuring of DC Loop

Resistance:

a) Bridge Meggar.

b) Digital Multimeter.

114

SIGNAL TO NOISE RATIO (SNR)

The ratio of signal to noise, an indication of

signal quality in analog system.

For DSL SNR > 7

For IPTV SNR > 10

115

CROSSTALK / TWISTED PAIR

The noise on a line caused by signals traveling

along another line.

Electromagnetic interference from one pair, can

create a noise over others pairs.

For the solution for this problem, is that the wire

pairs are twisted around each other at regular

intervals (between 2 and 12 twist per foot).

116

TYPES OF FAULTS

Insulation is that property of insulating material that

opposes the leakage of electricity through it .

Earth is touching of A or B wire with such a point which

resists flowing of current likely with each other or cabling

sheath.

A

B

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Break of A or B wire from anywhere is known as Break

Fault.

Contact is touching of A or B wire with each other of

same pair

Cross Contact Joining of A or B wire of one pair to the

other pair

Types of Faults (Cont’d)

A

B

A

B

A

B

A

B

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LOCALIZATION & RECTIFICATION

For the rectification of any faults different tests

are performed for the localization of fault, after

which these faults are removed. These are:

1. Insulation Test

2. Earth Test

3. Cross / Cross Contact Test

4. Break Test

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INSULATION TEST

High resistance in case of good insulation.

Minimum Standard Insulation of underground

Cable is 5000 Mega Ohms/km

120

EARTH TEST

Low resistance in case of good earth

121

CONTACT/CROSS CONTACT TEST

In case of contact between two wires current

get the short alternate path hence low

resistance.

122

BREAK TEST

Current didn’t find a path to flow hence high

resistance.

123

TESTING INSTRUMENTS

Digital Meggar

Cable Fault Locator (mTDR-070)

Cable Route Locator

Digital Earth Tester

Multimeter

LQT (Line Quality Tester)

124

DIGITAL MEGGAR

Meggar is a high voltage, low

current insulation tester, which is

used for two basic insulation tests.

Insulation to Ground

Insulation between Conductors

125

NanoTronix CABLE FAULT LOCATOR (mTDR-070)

Time Domain Reflectometer

transmitting high frequency

pulses which are reflected by any

impedance defect in the cable

under test. The signature of the

fault are interpreted by moving

the curser at the beginning of the

curve and the distance to the fault

is indicated.

126

NanoTronix Cable Fault Locator

(mTDR-070)

It can test following faults of cable from a remote distance

• complete open & short,

• partial open & short,

• loose connection,

• broken lines

Break Fault _____

Contact/Earth ……..

127

NanoTronix Cable Fault Locator

(mTDR-070)

128

ROUTE LOCATOR (Metrotech 9800 Series)

This device is used to locate the route and the

depth of underground cable.

This meter consists of two parts

A Transmitter and a Receiver

129

DIGITAL EARTH TESTER

Earth is a easy path for the flow

of high current, which is tested

by Digital Earth Tester.

Standard Parameter to be

tested:

Exchange

(x Lines)

Earth Resistance

(Ohms)

500 10

1000 5

2000 2.5

Above 2000 0.5

130

MULTIMETER

Used for measuring resistance, DC/AC

Voltage and current.

• [1] Function/Range Switch: selects the

function (voltmeter, ammeter, or ohmmeter)

and the range for the measurement.

• [2] COM Input Terminal: Common ground,

used in ALL measurements.

• [3] V Input Terminal: for voltage or

resistance measurements.

• [4] 200 mA Input Terminal: for small

current measurements.

• [5] 10 A Input Terminal: for large current

measurements.

• [6] Low Battery LCD: appears when the

battery needs replacement

131

LQT (Line Quality Tester)

XGXC XG204

Automatically match with the ADSL

line standards

Support ADSL2+ and ADSL2

Testing Parameters:

SNR for DSL Line > 10

Attenuation < 45dB

132

Line Qualification Criteria

Test

Parameters

Recommended

Values

Comments

Attenuation

(Downstream/

Upstream)

Less than 45 dB < 30 dB is excellent

30-40 dB is very good

40-45 dB – Little or no connectivity issues

45-60 dB – Connectivity issues

progressively become worse

> 60 dB – will experience no synch or

intermittent synchronization problems

Signal to

Noise Ratio

Greater than 10 < 6 – will experience no synch or

intermittent synch problems

6 - 10 – does not leave much room for

variances in condition

10 - 20 – Little or no synch problems

> 20 dB is excellent

133

Cable Route, Ducts, Manhole and their types

134

CABLE ROUTES

Before laying cable route be selected with proper

inspections, surveys and testing. At regular

intervals test pits be dig out to check underground

installations and hindrances. The road and other

local authorities may be consulted and their

existing and further planning maps be studied.

Proper selected cable prolonged the life of cable

and reduces the laying cost.

135

INSTRUCTION FOR SELECTION OF CABLE ROUTES

It should be short as possible

Other underground installations may be avoided

as much as possible.

Road and Railway crossing may be avoided.

Route should be earth and be free from chemical

injuries.

Route should follow the approved road and

streets.

Route should be as far away from the edge of

the metal road as possible.

136

INSTRUCTION FOR SELECTION OF CABLE ROUTES

The route may not pass through the private land

and expansion of building be taken under

consideration.

Narrow streets and congested bazaars may be

avoided.

Low cost of execution and reinstatement.

Less hindrance to traffic.

Safety to the workman during operation.

137

TYPES OF CABLE DUCTS

Cement concrete (precast and cast-in-site) re-

enforced or non-reinforced ducts.

Cement asbestos.

Earthenware or burnt clay ducts.

Fiber ducts.

Steel ducts.

Pipe/PVC conduit.