The 25 pair color code is a color code used to identify individual conductors in a kind of electrical communication wiring known as twisted pair cables. The colors are applied to the insulation that covers each conductor. The first color is chosen from one group of five colors and the other from a second group of five colors, giving 25 combinations of two colors.
The first group of colors is, in order: 'white, red, black, yellow, violet'.
The second group of colors is, in order: 'blue, orange, green, brown, slate'.
(The color violet is more commonly called purple, but in the telecommunications industry it is always referred to as violet. Similarly, slate is a particular shade of gray.)
One of the most common uses of the codes is in Category 5 computer network wiring, as used for structured cabling for switched Ethernet installations, where only the codes for the first four pairs are used.
Sometimes each wire in a pair will have a colored stripe matching the color of its paired wire. This makes it easy to identify which pair a given wire belongs to. Otherwise, to determine which pair a wire belongs to one has to note which color codes are physically twisted together.
Pair # | First wire | Second wire |
---|---|---|
1 | White | Blue |
2 | White | Orange |
3 | White | Green |
4 | White | Brown |
5 | White | Slate |
6 | Red | Blue |
7 | Red | Orange |
8 | Red | Green |
9 | Red | Brown |
10 | Red | Slate |
11 | Black | Blue |
12 | Black | Orange |
13 | Black | Green |
14 | Black | Brown |
15 | Black | Slate |
16 | Yellow | Blue |
17 | Yellow | Orange |
18 | Yellow | Green |
19 | Yellow | Brown |
20 | Yellow | Slate |
21 | Violet | Blue |
22 | Violet | Orange |
23 | Violet | Green |
24 | Violet | Brown |
25 | Violet | Slate |