Category 3 cable

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Category 3 cable, commonly known as Cat 3 or station wire, and less commonly known as VG or voice-grade (as, for example, in 100BaseVG), is an unshielded twisted pair (UTP) cable used in telephone wiring. It is part of a family of copper cabling standards defined jointly by the Electronic Industries Alliance and the Telecommunications Industry Association and published in TIA/EIA-568-B.

Although designed to reliably carry data up to 10 Mbit/s,[1] modern data networks run at much higher speeds, and Cat 5e or Cat 6 is now used for all new installations.


Cat3 was widely used in computer networking in the early 1990s for 10BASE-T Ethernet and, to a lesser extent, for 100BaseVG Ethernet, token ring and 100BASE-T4. The original Power over Ethernet 802.3af specification supports the use of Cat 3 cable, but the later 802.3at Type 2 high-power variation does not.[2]


From the early 2000s new structured cabling installations were almost invariably built with the higher performing Cat 5e cable required by 100BASE-TX. Cat 5e or Cat 6 is now used for all modern structured cabling installations. Many large institutions which require any repairs or additions to existing buildings that currently use Cat 3 have policies requiring upgrade to Cat 5e.[3]

See also[edit]


  1. ^ "CCNA: Network Media Types". Cisco Systems. Retrieved 2017-09-05. 
  2. ^ IEEE 802.3at-2009, clause 33.1.1c
  3. ^ "University of Wisconsin – Standards for the Installation of New Data/Voice Jacks". Retrieved 2013-09-17. 

External links[edit]