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 over variations are available. EIA/TIA specifies RJ-45 connectors (ISO 8877) for UTP (unshielded twisted pair) cable.

Pin	Name	Description	EIA/TIA 568A cable colors	EIA/TIA 568B or AT&T 258A cable colors
1	TX+	Tranceive Data+	White with green strip	White with orange stripe
2	TX-	Tranceive 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 strip or solid brown	White with brown strip or solid brown
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 Hub's (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.