A-1
Cisco 7204 Installation and Configuration Guide
OL-5101-02
A P P E N D I X
A
Industry-Standard Wiring Plans
When you install more than a few terminals, you face the problem of organizing the wiring. AT&T has
devised a uniform scheme for dealing with large numbers of wires for the telephone industry. The
scheme uses two color codes—one for large numbers of wires organized in pairs and the other for smaller
numbers of wires that may also be organized in pairs. We recommend the use of this wiring scheme
whenever possible.
For large numbers of wires, each pair is assigned a two-color code. The colors are selected from two
groups of five, 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 within group” are blue, orange, 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.
Table A-1
lists the sequences. Note that red-brown and red-orange wires can be easily confused.
Table A-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
2
2
Orange
White
2
3
1
White
Green
28
3
2
Green
White
3
4
1
White
Brown
29
4
2
Brown
White
4
5
1
White
Slate
30
5
2
Slate
White
5
6
1
Red
Blue
31
6
2
Blue
Red
6
7
1
Red
Orange
32
7
2
Orange
Red
7
8
1
Red
Green
33
8
2
Green
Red
8
