CAT5e Wiring Diagram
Pin |
Name |
Description |
EIA/TIA 568A cable colors |
EIA/TIA 568B cable colors (most common) |
1 | TX+ | Transmit Data+ |
Green / White |
Orange / White |
2 | TX- | Transmit Data- |
Green |
Orange |
3 | RX+ | Receive Data+ |
Orange / White |
Green / White |
4 | n/c | Not connected |
Blue |
Blue |
5 | n/c | Not connected |
Blue / White |
Blue / White |
6 | RX- | Receive Data- |
Orange |
Green |
7 | n/c | Not connected |
Brown / White |
Brown / White |
8 | n/c | Not connected |
Brown |
Brown |
- Length of CAT5 cable runs should not exceed 100 meters.
- It is very important that a single pair be used for pins 1 and 2; 3 and 6. If not, performance will degrade.
CAT5 Splitter Trick
Given that Pins 4-5,7-8 are not used in a standard 100MB connection, it is possible to attach a second RJ45 jack which places these wires in the 1-2,3-6 position in the jack. This allows you to run 2 connections over a single cable. While this trick works, it is probably not ideal and could cause packet loss. I have done this for non-critical equipment such as network printers. This trick does not work with Gigabit links as they require all 8 pins.