Category 4 cable

Category 4 cable (Cat 4) is a cable that consists of four unshielded twisted pair (UTP) copper wires supporting signals up to 20 MHz.[citation needed] It is used in telephone networks which can transmit voice and data up to 16 Mbit/s.[1]

For a brief period it was used for some token ring,[2] 10BASE-T, and 100BASE-T4 networks, but was quickly superseded by Category 5 cable. It is no longer common or used in new installations and is not recognized by the current version of the TIA/EIA-568 data cabling standards.