CAT-5, short for Category 5, is a type of twisted pair cable commonly used in Ethernet networks and data communication applications.
Category 5 (CAT-5) cable is part of the family of standardized twisted pair cables used for transmitting data signals in local area networks (LANs) and other communication systems. It typically contains four pairs of insulated copper conductors twisted together to minimize electromagnetic interference (EMI) and reduce crosstalk between pairs. CAT-5 supports data transfer speeds up to 100 Mbps (Fast Ethernet) at frequencies up to 100 MHz, making it suitable for earlier generations of Ethernet-based systems.
Although largely replaced by newer categories such as CAT-5e, CAT-6, and CAT-6A, CAT-5 remains an important milestone in network cabling history. Its balance of performance and cost-efficiency made it a standard choice for commercial, industrial, and audiovisual installations throughout the 1990s and early 2000s. In AV environments, it was often used as a patch cable for connecting devices like switches, routers, and distribution systems, offering dependable signal transmission in moderate-bandwidth applications.
CAT-5 cables are defined by the Telecommunications Industry Association (TIA) under the TIA/EIA-568 standard. Compliance with these specifications ensures that CAT-5 cabling systems meet required performance levels for data rate, frequency, and signal integrity across Ethernet and structured cabling applications.
Introduced in the early 1990s, CAT-5 quickly became the benchmark for Ethernet networks, supporting 10Base-T and 100Base-TX (Fast Ethernet) protocols. As data demands increased, enhanced versions like CAT-5e were developed to handle higher transmission rates and improved crosstalk performance. Though now considered a legacy standard, CAT-5 cabling remains in operation within many older commercial systems and continues to inform modern network design principles.