Category 3 cable, commonly known as or station wire, and less commonly known as VG or voice-grade (as, for example, in
100BaseVG
100BaseVG is a 100 Mbit/s Ethernet standard specified to run over four pairs of category 3 cable (cable also known as voice grade, hence the "VG"). It is also called 100VG-AnyLAN because it was defined to carry both Ethernet and Token Ring ...
), is an
unshielded twisted pair (UTP) cable used in
telephone
A telephone is a telecommunications device that permits two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most efficiently the human voice, into e ...
wiring. It is part of a family of standards defined jointly by the
Electronic Industries Alliance (EIA) and the
Telecommunications Industry Association (TIA) and published in
TIA/EIA-568-B
ANSI/TIA-568 is a technical standard for commercial building cabling for telecommunications products and services. The title of the standard is ''Commercial Building Telecommunications Cabling Standard'' and is published by the Telecommunications I ...
.
Although designed to reliably carry data up to 10 Mbit/s, modern data networks run at much higher speeds, and or better cable is generally used for new installations.
Networking
was widely used in
computer network
A computer network is a set of computers sharing resources located on or provided by network nodes. The computers use common communication protocols over digital interconnections to communicate with each other. These interconnections are ...
ing in the early 1990s for
10BASE-T Ethernet and, to a much lesser extent, for
100BaseVG
100BaseVG is a 100 Mbit/s Ethernet standard specified to run over four pairs of category 3 cable (cable also known as voice grade, hence the "VG"). It is also called 100VG-AnyLAN because it was defined to carry both Ethernet and Token Ring ...
Ethernet,
Token Ring and
100BASE-T4
In computer networking, Fast Ethernet physical layers carry traffic at the nominal rate of 100 Mbit/s. The prior Ethernet speed was 10 Mbit/s. Of the Fast Ethernet physical layers, 100BASE-TX is by far the most common.
Fast Ether ...
. The original
Power over Ethernet
Power over Ethernet, or PoE, describes any of several standards or ad hoc systems that pass electric power along with data on twisted-pair Ethernet cabling. This allows a single cable to provide both data connection and electrical power to ...
802.3af specification supports the use of cable, but the later 802.3at Type 2 high-power variation does not.
[IEEE 802.3at-2009, clause 33.1.1c] In some use cases and for short distances, Cat 3 may be capable of carrying 100BASE-TX (2 pairs) or even 1000BASE-T (4 pairs). Such use cases include hobbyist retrofitting short home telephone Cat 3 networks for Ethernet.
Dedicated 100BASE-T4 networks, supporting 100 Mbit/s over Cat 3, appear to have been a rarity as very few network interface controllers and switches were ever released. Some examples include the
3com
3Com Corporation was an American digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others. Bill Krause joined as President in 1981. Metcalfe e ...
3C250-T4 Superstack II HUB 100,
IBM 8225 Fast Ethernet Stackable Hub and
Intel
Intel Corporation is an American multinational corporation and technology company headquartered in Santa Clara, California. It is the world's largest semiconductor chip manufacturer by revenue, and is one of the developers of the x86 ser ...
LinkBuilder FMS 100 T4. The same applies to
network interface controller cards. Bridging 100BASE-T4 with 100BASE-TX required additional network equipment.
Replacement
Starting in the mid-1990s, new
structured cabling
In telecommunications, structured cabling is building or campus cabling infrastructure that consists of a number of standardized smaller elements (hence structured) called subsystems. Structured cabling components include twisted pair and op ...
installations were often built with the higher performing cable required by
100BASE-TX. or is now used for all modern structured cabling installations. Many large institutions have policies that any upgrade to a network using must involve upgrading to .
See also
*
Copper cable certification
In copper twisted pair wire networks, copper cable certification is achieved through a thorough series of tests in accordance with Telecommunications Industry Association (TIA) or International Organization for Standardization (ISO) standards. T ...
References
External links
How Low Voltage Cable is Made - Cat5e, Cat6, Cat3 and OSP
{{DEFAULTSORT:Category 3 Cable
Ethernet cables