Cat5, or Category 5, is a type of twisted pair cable used for networking and telecommunications. It supports data transmission speeds of up to 100 Mbps and is commonly used in local area networks (LANs). The cable consists of four pairs of wires twisted together to reduce interference and improve signal quality. Introduced in the 1990s, Cat5 cables are often used for connecting computers, routers, and switches. While they have largely been replaced by faster standards like Cat5e and Cat6, they are still found in many older installations and can effectively support basic internet and network functions.