Category 4 cable (Cat 4) is a cable that consists of eight copper wires arranged in four unshielded twisted pairs (UTP) supporting signals up to 20 MHz.[1] It is used in telephone networks which can transmit voice and data up to 16 Mbit/s.[2]
For a brief period it was used for some Token Ring,[3] 10BASE-T, and 100BASE-T4 networks, but was quickly superseded by Category 5 cable.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 ANSI/TIA-568 data cabling standards.