8 pin RJ45 (8P8C) female connector at the network interface cards/hubs
8 pin RJ45 (8P8C) male connector at the cables.
10BASE-T (IEEE 802.3i, 1990) and 100BASE-TX (IEEE 802.3u, 1995) are the most common forms of Ethernet over twisted-pair copper, both using the 8-position 8P8C modular connector usually called RJ-45. Each uses two of the four pairs — pins 1 & 2 for transmit and pins 3 & 6 for receive — over Category 3 (10BASE-T) or Category 5 (100BASE-TX) cable, with a maximum segment length of 100 m. The connector and wiring are the same as for 1000BASE-T gigabit Ethernet, which additionally uses the remaining two pairs.
| Pin | Name | Description | TIA/EIA 568A | TIA/EIA 568B |
|---|---|---|---|---|
| 1 | TX+ | Tranceive Data+ | 
white/green | 
white/orange |
| 2 | TX- | Tranceive Data- | 
green | 
orange |
| 3 | RX+ | Receive Data+ |
white/orange |
white/green |
| 4 | n/c | 
blue |
blue | |
| 5 | n/c | 
white/blue |
white/blue | |
| 6 | RX- | Receive Data- |
orange |
green |
| 7 | n/c | 
white/brown |
white/brown | |
| 8 | n/c | 
brown |
brown |
Notes
- T568A and T568B are the two color codes used for wiring eight-position RJ45 modular plugs. Both are allowed under the ANSI/TIA/EIA wiring standards. The only difference between the two color codes is that the orange and green pairs are interchanged. T568A wiring pattern is recognized as the preferred wiring pattern for this standard because it provides backward compatibility to both one pair and two pair USOC wiring schemes. The T568B standard matches the older ATA&T 258A color code and is/was(?) the most widely used wiring scheme. It is also permitted by the ANSI/TIA/EIA standard, but it provides only a single pair backward compatibility to the USOC wiring scheme. The U.S. Government requires the use of the preferred T568A standard for wiring done under federal contracts.
- Length of CAT5 cable runs should not exceed 100 meters.
- TX and RX signals are swapped on Hub’s. 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.