Telecom: 25-Pair Cable Colors

In voice system wiring, 25-pair cables are common. 25 pairs is a T1's worth of circuits, with a spare. A 25-pair cable is usually terminated with a 50-pin amphenol connector, and it clamps right onto a 66-block. Many PBXs also have this type of connector for their outside connections.

A 25-pair cable contains 5 groups of 5 pairs each, color coded to show the pair numbers. The first group of 5 has the following colors (the first 4 pairs are the same colors as you find in a 4-pair Cat-5 cable):

Pair Colors

1 blue and white (or blue and white/blue)

2 orange and white (or orange and white/orange)

3 green and white (or green and white/green)

4 brown and white (or brown and white/brown)

5 grey and white (or grey and white/grey)

and so on where the second group of 5 is red instead of white, third group with black, fourth is yellow and fifth is violet. (See also this site - www.cabling-design.com).

  $Log: paircolr.htm,v $
  Revision 1.1  2000/06/21 05:09:59  lars
  Added cross-references, and supporting links.
  Added 25-pair color code.

Pair	Colors
1	blue and white (or blue and white/blue)
2	orange and white (or orange and white/orange)
3	green and white (or green and white/green)
4	brown and white (or brown and white/brown)
5	grey and white (or grey and white/grey)