I used to have a telephone manuel from the late 30'searly 40's that had the standard (current) Color code. The determining factor for using the colors that they did, had to do with the ease of identification along with the availability of dyes for cloth cordage. IE they wanted cheap easy to use dyes that were easy to identify. .In cable constructions containing more than 25pair, the colors are repeated as necessary. Color coded binders are used to identify 25pair groups of color coded pairs. Pair Identification Colors Pair Number Tip Color Ring Color 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 telephone cable color chart
Colour Chart for Telephone Wiring over CAT5 cables (UK US) If you haven't already done so, check out Dr. Gadget's Wiring Wizard, which may save you the need to get into this level of detail. . I hope you find the charts below useful.
4SProducts Copper Cable Assemblies Technical Data Sheet Color Code Charts Copper Cables Color code schemes are used to identify wires within a cable. You may encounter two different wire color schemes while working on your phone wiring. The simplest color scheme is used on normal station cable (what your phone tech may call JK ), which has only two pairs of wire. The first pair has one green wire ( tip ) and one red wire ( ring ).telephone cable color chart Technical Information Telecommunications Color Code Chart PLASTIC INSULATED COMMUNICATION CABLES 25 PAIR UNIT COLORS PAIR NUMBER RING COLOR TIP COLOR PAIR NUMBER RING COLOR TIP COLOR 1 Blue White 13 Green Black 2 Orange White 14 Brown Black 3 Green White 15 Slate Black 4 Brown White 16 Blue