Introduction  

The aim of this document is to standardise the cable specifications and colour codes used for all new computer installations using equipment supplied by the EDP Group of companies.

In the past, Customers and their Agents, have not followed or have not supplied with relevant information relating to cable specifications and interface cable installation requirements. This failure has resulted in the impaired operation of their computer system and the subsequent waste of both the customers and EDP's time whilst remedial action took place.

If a Customer, or their Agents, fail to comply with the requirements of this document then EDP may require full payment to cover both time expended and materials used whilst engaged in remedial action.

It is strongly recommend that customers arrange for trained EDP Personnel to terminate their interface cables.

Arrangements can be made by contacting EDP's Service Centre on 01908 249700.

THE CABLE SPECIFICATIONS DETAILED IN THIS DOCUMENT SUPERCEDE ALL PERVIOUS RELEASES.
Cable Installation Requirements
  1. The EDP Group of companies only recommend the use of FTP(Foil Screened Twisted Pairs) for all CAT 5 and subsequent, Structured cabling. This is also to include all patch and fly leads. This is a requirement of EDP's suppliers and is mandatory.
  2. EDP recommend the following specifications for CAT 5 cabling connected to equipment
    • Category 5 enhanced FTP 4 pair patch cable
    • 4 twisted pairs
    • Foil shrouded with earth wire
    overall size
    5.7mm
    conductors
    7/0.18mm
    Characteristic Impedance
    100
    Resistance
    110 /km
    Capacitance per m
    56pF
    Attenuation per 100m @ 1 MHz 
    3.2Db

  1. For general use, non-structure, the EDP Group of Companies only recommend the use of the above category 5 enhanced FTP 4 pair patch cable, Belden 9504, Belden 8723 or equivalent. For most applications 4 pair cable is mandatory

4. For each conductor within a cable specification a colour code has been assigned i.e

White             Black from white
Red                Yellow/ Blue
Black              White with Orange
Green             etc.
The failure to comply with this colour code could cause intermodulation between conductors and subsequent machine failure. It is mandatory that this colour coding is adhered to unless a "structured cabling system" is being installed.

  1. The original cable specifications were written with the colour coding of Belden 9504 if you are using the cat 5 cable the following cross reference chart must be used for colour coding. The complete cable specifications will not be reissued with the revised colours.
Existing Belden colours
New CAT 5 colours
Red
Black paired with Red
Orange
White / Orange
Blue
Black paired with Blue
Blue
White / Blue
Green
Black paired with Green
Green
White / Blue
White
Black paired with White
Brown
White / Brown
  1. It is mandatory that only screened cable is used. The screen or foil must be connected to earth at one point only, and this is usually Pin 1 on a 25D-Type connector at the peripheral end. The screen should be DC continuous for the length of the cable run. Where building structured cabling is used the following assumption is made. THERE IS NO CONTINUOUS DC PATH BETWEEN THE METAL SHIELDS OF THE RJ45 CONNECTORS. Therefore each cable supplied must have its screen earthed separately and independently from the shield, which must be connected to an earth. The Fly Lead (Wall Socket to Peripheral), has it's screen earthed via the peripheral, usually at Pin 1 on a 25D-Type connector.

If the above assumption does not hold true, then the screen earthing may have to be modified to suit the particular site. Failure to comply with this could result in interference radio frequency pick-up and subsequent failure of the computer system.

  1. The plugs and sockets must be soldered to the interface cable. EDP does not recommended the use of the crimped cable ends. There should not be any stray strands of wire or solder splashes; as these could cause permanent or intermittent short circuits; which could result in either failure of the computer system or the corruption of data.

  2. Where a Customer supplies their own plugs and sockets care should be taken to ensure they can be securely retained when fitted the computer system, wall socket, or peripheral

  3. it is strongly recommended Customers obtain plugs and sockets from EDP. Orders can be placed with EDP's Supplies Division on: 01908 249797

  4. EDP will be happy to assist you with any problem relating to interface cable installation

  5. For assistance please contact Engineering Services on: 01908 249700