100Mbps Ethernet on Twisted-Pair Cabling
During the 100Mbps Ethernet development effort, three separate teams of engineers pursued different technical approaches to pushing 100Mbps across twisted–pair cabling. As a result, three distinct twisted-pair physical specifications were written:
100BASE-TX—This version was marketed first and is by far the most popular. It runs across two pairs of wires, either Category 5 UTP cable or IBM Type 1 shielded twisted–pair cable.
100BASE-T4—This version runs across four Category 3 (or better) twisted pairs. Although far less popular than the TX version, it is useful for environments that do not have either Category 5 or shielded twisted-pair cabling. It has some shortcomings, however: The worst is ...