Networking Guide : Cat 5 Wiring Scheme

Picture: 568A vs. 568B
Pin and pair designation in two EIA/TIA standards.

A Cat 5 cable is terminated with RJ-45 connectors. RJ-45 connector is a modular connector that has 8 pins. Pins 1, 2, 3, and 6 are used for transmit and receive. Pins 4, 5, 7, and 8 are unused. The picture above shows wiring in RJ-45 connector with the pins on the top and the tab on the bottom. In this position, Pin 8 is the rightmost and Pin 1 is the leftmost.

Picture: Two RJ-45 connectors terminates a Cat 5 cable.
Cat 5e and Cat 6 cables are also terminated with RJ-45 connectors.

If you buy a Cat 5 cable that hasn't been terminated and decide to install RJ-45 connectors on your own, you may need a crimping tool to help you cut the wires and insert the wires tips into the pins.

Picture: Crimping Tool

Video: DIY making a network cable