25 Pair Color Code
The 25-pair color code is used to identify individual conductors in a telecommunications twisted pair cable. The colors are marked on the conductors insulation. The first (or major) color is chosen from one group of five colors and the other (or minor) color from a second group of five colors, giving 25 combinations of two colors. The tip is always first, and pairs should never be split.
|Major colors:||Tip (+)||White||Red||Black||Yellow||Violet||'A' wire|
|Minor colors:||Ring (-)||Blue||Orange||Green||Brown||Slate||'B' wire|
Note: Telecom equipment is "positive ground": tip is 0 volt with respect to ground (earth), ring is -50 volt.
|No.||Pair||Major color / Tip (A)||Minor color / Ring (B)|