CWS HOME SECURITY USA

RJ-45

The RJ-45 connector is commonly used for network cabling and for telephony applications. It's also used for serial connections in special cases. Here's a look at it:

Pinout for Ethernet

Although used for a variety of purposes, the RJ-45 connector is probably most commonly used for 10Base-T and 100Base-TX Ethernet connections.

Pin #	Ethernet 10BASE-T 100BASE-TX	EIA/TIA 568A	EIA/TIA 568B or AT&T 258A
1	Transmit +	White with green strip	White with orange stripe
2	Transmit -	Green with white stripe or solid green	Orange with white stripe or solid orange
3	Receive +	White with orange stripe	White with green stripe
4	N/A	Blue with white stripe or solid blue	Blue with white stripe or solid blue
5	N/A	White with blue stripe	White with blue stripe
6	Receive -	Orange with white stripe or solid orange	Green with white stripe or solid green
7	N/A	White with brown strip or solid brown	White with brown stripe
8	N/A	Brown with white stripe or solid brown.	Brown with white stripe or solid brown

Because only two pairs of wires in the eight-pin RJ-45 connector are used to carry Ethernet signals, and both 10BASE-T and 100BASE-TX use the same pins, a crossover cable made for one will also work with the other.

Also, please note that it is very important that a single pair be used for pins 3 and 6. If one conductor from one pair is used for pin 3 and a conductor from another pair is used for pin 6, performance will degrade. See the following figure.