T568A/B RJ45 Wiring

Pin	T568A Pair	T568B Pair	Wire	T568A Color	T568B Color	Pins on plug face (jack is reversed)
1	3	2	tip
2	3	2	ring
3	2	3	tip
4	1	1	ring
5	1	1	tip
6	2	3	ring
7	4	4	tip
8	4	4	ring

Note that the only difference between T568A and T568B is that pairs 2 and 3 (orange and green) are swapped. Both standards wire the pins "straight through", i.e., pins 1 through 8 on one end are connected to pins 1 through 8 on the other end. Also, the same sets of pins are paired in both standards: pins 1 and 2 form a pair, as do 3 and 6, 4 and 5 and 7 and 8. And although many cables implement some small electrical differences between pairs, these effects are negligible, so cables wired to either standard are interchangeable. UTP cables terminated according to T568A on one end and T568B on the other end are known as Ethernet crossover cables.

 

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Category 5 cable".