Straight and crossover cable color code
UTP has 4 twisted pairs of wires, we’ll now look at the pairs to see what colour codes they have:
As you can see in the picture above, the 4 pairs are labeled. Pairs 2 & 3 are used for normal 10/100Mbit networks, while Pairs 1 & 4 are reserved. In Gigabit Ethernet, all 4 pairs are used.
UTP CAT5, 5e & 6 cable is the most common type of UTP around the world ! It’s flexible, easy to install and very reliable when wired properly.
There are two wiring standards for these cables, called “T568A” (also called “EIA”) and “T568B” (also called “AT&T” and “258A”). They differ only in connection sequence – that is, which color is on which pin, not in the definition of what electrical signal is on a particular color.
Pin Number Designations for T568B-T568B
Note that the odd pin numbers are always the white with stripe color (1,3,5,7). The wires connect to RJ-45 8-pin connectors as shown below:
Color Codes for T568B
Pin????? Color? Pair Name
1??? white/orange (pair 2)? TxData +
2??? orange (pair 2)?????????? TxData –
3??? white/green (pair 3)??? RecvData+
4??? blue (pair 1)
5??? white/blue (pair 1)
6??? green (pair 3)???????????? RecvData-
7??? white/brown (pair 4)
8??? brown (pair 4)
Pin Number Designations for T568A
The T568A specification reverses the orange and green connections so that pairs 1 and 2 are on the centre 4 pins, which makes it more compatible with the telecom voice connections. (Note that in the RJ-11 plug at the top, pairs 1 and 2 are on the centre 4 pins.) T568A goes