TIA/EIA 568A
Standard for terminating 100 Ohm Unshielded Twisted Pair (UTP) cable on RJ-45 Connector
Terminating 100 Ohm Unshielded Twisted Pair (UTP) cable for use with Ethernet to be terminated on RJ-45 connectors. Wiring standard released in 1991. This was updated in 1995 to TIA/EIA-568B. The only difference between T568A and T568B is that pairs 2 and 3 (orange and green) are swapped.