Definition: CAT5 is an Ethernet network cable standard defined by the Electronic Industries Association and Telecommunications Industry Association (commonly known as EIA/TIA). CAT5 is the fifth generation of twisted pair Ethernet technology and the most popular of all twisted pair cables in use today.
CAT5 cable contains four pairs of copper wire. It supports Fast Ethernet speeds (up to 100 Mbps). As with all other types of twisted pair EIA/TIA cabling, CAT5 cable runs are limited to a maximum recommended run length of 100m (328 feet). A newer specification for CAT5 cable – CAT5 enhanced (CAT5e) – supports networking at Gigabit Ethernet speeds (up to 1000 Mbps) over short distances by utilizing all four-wire pairs, and it is backward compatible with ordinary CAT5.