Short for Category 5, a common type of twisted pair cable. Cat 5 cable is used in many networking environments for high speed data transfer. It is the current standard (replacing the former standard, Cat 3 cable) for Ethernet and fast Ethernet networks, where it is generally terminated with an RJ-45 type connector (similar to the connector many telephones use). The “category 5” standard states the twisted pairs must have at least 8 twists per foot. There are other category standards with different specifications, but Cat 5 is the most widely known and used at the consumer level right now. Most modern computers have RJ-45 type connectors built in to them for networking connections. Since this configuration has become such a common standard, component parts are widely available and inexpensive, which has caused even more widespread usage. As such we are beginning to see these connectors and cables used on more and more music equipment for certain types of communication.