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 frame types. 100BaseVG was originally proposed by Hewlett-Packard, ratified by the IEEE in 1995 and was practically extinct by 1998. In 2001 IEEE recorded the status of its 100BaseVG standard as being a "Withdrawn Standard" (defined as "A standard which is no longer maintained and which may contain significant obsolete or erroneous information.") Standardization 100BaseVG started in the IEEE 802.3 committee as Fast Ethernet. One faction wanted to keep carrier-sense multiple access with collision detection (CSMA/CD) in order to keep it pure Ethernet, even though the collision domain problem limited the distances to one tenth that of 10BASE-T. Another faction wanted to change to a polling architecture from the hub (they called it "Demand Priority Protocol") in order to maintain the 10BASE-T distances, and also to make it a deterministic protocol. The first faction argued that, since IEEE 802.3 was the Ethernet committee, it was not the place to develop a different protocol. Thus, the IEEE 802.12 committee was formed and standardized 100BaseVG. Physical layer The physical layer requires four twisted pairs of "voice-grade" cabling for a link, so category 3 cables or better can be used. While control signaling uses two pairs for each direction simultaneously, all four pairs are switched to a single direction during data transmission, as required and defined during control signaling. This makes 100BaseVG an inherently half-duplex medium like e.g. 10BASE5 (yet faster) but without the CSMA/CD drawbacks. 100BaseVG also supports full-duplex operation over optical fiber or over two pairs of shielded twisted pair. 100VG-AnyLAN vs. Fast Ethernet Multiplexing Instead of following the Fast Ethernet standard for twisted pair cabling by using only 2 pairs of wires, 100VG-AnyLAN used all four pairs in either Category 3 or Category 5 twisted pair cable. The design goals were to avoid the radio frequency radiation emitted at the higher frequencies required by Fast Ethernet and to leverage existing wiring installations of Category 3 cabling that most organizations had recently installed to support 10 megabit twisted-pair Ethernet. This had the additional advantage of being less susceptible to external sources of RF interference such as other network cables, fluorescent lights, and high power lines. They multiplexed the signal