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 strip  |
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 strip |
White with brown strip |
| 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.
