Category 3 Cable


Category 3 cable, commonly known as Cat 3, is an unshielded twisted pair (UTP) cable designed to reliably carry data up to 10 Mbit/s, with a possible bandwidth of 16 MHz. It is part of a family of copper cabling standards defined jointly by the Electronic Industries Alliance and the Telecommunications Industry Association. Category 3 was a popular cabling format among computer network administrators in the early 1990s, but fell out of popularity in favor of the very similar, but higher performing, Cat 5 standard. Now that Cat 5 is obsolete, most new structured cable installations are built with Cat 5e or Cat 6 cable. Cat 3 is currently still in use in two-line telephone systems, although Cat 5 or higher could do the same work and allow transition to VOIP.


Note that unlike Cat 1,2,4, and 5 cables, Cat 3 is still recognized by TIA/EIA-568-B, its defining standard.

Category 3 saw some extra longevity due to the 100baseT4 standard which achieved speeds of 100 Mbit/s by using all 4 pairs of wires. This allowed businesses that were already wired for Cat 3 to keep their current wiring but still upgrade to 100 Mbit/s.

Other categories of network cables
  • Cat 1: Currently unrecognized by TIA/EIA. Previously used for POTS telephone communications, ISDN and doorbell wiring.
  • Cat 2: Currently unrecognized by TIA/EIA. Previously was frequently used on 4Mbit/s token ring networks.
  • Cat 3: Current cable standard, used for data networks utilizing frequencies up to 16 MHz. Popular for 10 Mbit/s Ethernet networks.
  • Cat 4: Currently unrecognized by TIA/EIA. Provided performance of up to 20 MHz, and was frequently used on 16Mbit/s token ring networks.
  • Cat 6: Defined by the ANSI TIA/EIA 568B-2.1. It provides performance of up to 250 MHz, more than double category 5 and 5e.
  • Cat 6a: Operates at frequencies up to 500MHz and provides up to 10Gbit/s
  • Cat 7: Draft standard, proposed to include four individually-shielded pairs (ScTP) inside an overall shield. Designed for transmission at frequencies up to 650 MHz.