APPENDIX
Industry-Standard Wiring Plans B-1
B
Industry-Standard Wiring PlansWhen you order multiple internetwork systems, you face the problem of organi ze d wiring. In
response to this problem, AT&T has devised a uni form wiring scheme for the telephone industry.
The wiring scheme uses two color codes—one for a large number of wires that are organized int o
pairs, and one for a smaller number of wires that might also be or ganiz ed int o pairs . We recommend
the use of this wiring scheme whenever possible.
For large numbers of wires, each pa ir is as signed a two-color code. The col o r s ar e sel ected from 2
groups of 5, resulting in what is called a binder-group of 25 pairs. The colors used for a group are
white, red, black, yellow, and violet. The colors used for “pair wi thin group” a re bl ue , ora nge, green,
brown, and slate.
Each pair must have a unique color combination. One wire within each pair has a solid background
of its group color and stripes of the “pair within group” color; the second wire has the colors
reversed. TableB-1 lists the sequences. Note that red-brown and red-orange wires can be easily
confused.
TableB-1 Telephone Industry 25-Pair Color Code and Pin Numbers
Pair Number Wire Number Solid Color Stripe Color Pin Number
1 1 White Blue 26
1 2 Blue White 1
2 1 White Orange 27
22OrangeWhite 2
31WhiteGreen 28
32GreenWhite 3
41WhiteBrown29
42BrownWhite 4
51WhiteSlate 30
5 2 Slate White 5
61RedBlue 31
62BlueRed 6
7 1 Red Orange 32
72OrangeRed 7
81RedGreen 33
82GreenRed 8