Cat-5 - Describes network cabling that consists of four twisted pairs of copper wire terminated by RJ-45 connectors and capable of supporting data speeds of AT LEAST 100 Mbps.

Most LAN cabling today is Cat-5 (or better) to the workstations. This means, if you're on a LAN, the LAN cable running out of the back of your computer is Category 5.

Cat-5 is based on the EIA/TIA 568 Commercial Building Telecommunications Wiring Standard developed by the Telecommunications Industry Association (TIA) leg of the Electronics Industries Alliance (EIA). Sometimes, the term category 5 is used to refer to complete wiring installations that meet TIA-568 certification tests.