Color Code and Wire Order in a
Twisted-Pair Network Cable
Last updated: 11/10/04
Q. Does the order of the colors of the wires in a straight-thru
twisted-pair network cable matter as long as both ends are the cable are
wired the same?
A. Yes. You can use either standard color code,
or invent your own, if desired. I use the 568A color code and it is the “preferred
standard.” The colors do not matter, but the choice of wires does. Simply
making both ends the same is not sufficient. The Ethernet interface uses
four of the eight pins in an RJ-45 plug. Each end of an Ethernet cable connects
to a transmitter and a receiver. A transmitter uses two pins and a receiver
uses two pins. The two pins (+ and -) on the transmitter have to be connected
to the corresponding pins (+ and -) of the receiver at the other end by wires
in the SAME twisted pair and vice versa. A transmitter is not connected to
a receiver by one wire from one pair and a second wire from a DIFFERENT pair.
As the pins that are used, 1, 2, 3, and 6, are not sequential, one cannot
simply match ends in a convenient manner and properly connect a transmitter
to a receiver with wires from the SAME twisted pair. If this description
seems a bit complicated or fuzzy, pictures can be found at http://duxcw.com/digest/Howto/network/cable/cable5.htm.