RJ-45 (Registered Jack - Type 45) connectors look almost like standard telephone connectors.
They house eight wires as against four wires in a telephone connector. The actual concept was that the central two pins would be one pair, the next two the second pair, and so on until the outer pins of an eight-pin connector would be the fourth twisted pair.
Also, signal shielding was optimised by alternating the "live" and "earthy" pins of each pair. This pattern for the eight-pin connector resulted in a pinout where the outermost pair are then too far apart to meet the electrical requirements of high-speed LAN protocols.
RJ-45
|
Pin |
Signal Description |
Pin |
Signal Description |
|
1 |
Request To Send |
5 |
Ground |
|
2 |
Data Terminal Ready |
6 |
Receive Data |
|
3 |
Transmit Data |
7 |
Data Set Ready |
|
4 |
Ground |
8 |
Clear To Send |
