Twisted Pair (TP) wiring in an RJ45 connector

Straight through or crossover cable?

A straight through cable has wiring according to T568A in both end while a crossover cable has T568A wiring in one end and T568B in the other.

Straight through

Switch or Hub <-> Host
Switch or Hub <-> Router


Host <-> Host
Router <-> Router
Switch or Hub <-> Switch or Hub

Please note that lots of switches have a MDI/MDIX switch assigned to one port, ofter called UPLINK,  thus making it possible to use either a straight through or crossover cable. In some cases the switch is auto-sensing, so called Auto MDI/MDIX.

Wiring in an RJ45 connector (8P8C connector)



1    Orange / White
2    Orange
3    Green / White
4    Blue
5    Blue / White
6    Green
7    Brown / White
8    Brown



1    Green / White
2    Green
3    Orange / White
4    Blue
5    Blue / White
6    Orange
7    Brown / White
8    Brown

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