Ethernet 10/100Base-T ( RJ-45) connector pinout

Nowdays ethernet is a most common networking standard for LAN (local area network) communication, officially standardized by IEEE standard 802.3. Nowdays ethernet runs at 10Mb, 100Mb or 1Gb per second. It was originally developed by Xerox Corporation in cooperation with DEC and Intel in 1976. Ethernet uses a bus (old coaxial cable) or star topology (standard UTP cable). Most ethernet networks use unshielded twisted pair (UTP) cable. Category 5 (CAT5) cable widely used, but other variations are available. EIA/TIA specifies RJ-45 connectors - properly called 8P8C - (ISO 8877) for UTP (unshielded twisted pair) cable. (RJ45 refers to a set of connectors beyond the 8P8C standard but the former has replaced the latter in common usage).

Pin	Name	Description	EIA/TIA 568A cable colors	EIA/TIA 568B or AT&T 258A cable colors
1	TX+	Transmit Data+	White with green stripe	White with orange stripe
2	TX-	Transmit Data-	Green with white stripe or solid green	Orange with white stripe or solid orange
3	RX+	Receive Data+	White with orange stripe	White with green stripe
4	n/c	Not connected	Blue with white stripe or solid blue	Blue with white stripe or solid blue
5	n/c	Not connected	White with blue stripe	White with blue stripe
6	RX-	Receive Data-	Orange with white stripe or solid orange	Green with white stripe or solid
7	n/c	Not connected	White with brown stripe	White with brown stripe
8	n/c	Not connected	Brown with white stripe or solid brown	Brown with white stripe or solid brown

Length of CAT5 cable runs should not exceed 100 meters.

Note: TX & RX are swapped on Hubs (see crossover cable). Also, please note that it is very important that a single pair be used for pins 1 and 2; 3 and 6. If not, performance will degrade.