100BASE−T2 never was implemented in products. Nonetheless, the technology is of some interest because much of it was borrowed for 1000BASE−T, so it will be described here briefly.
Like 100BASE−T4, 100BASE−T2 was designed to run on Category 3 or better wiring. However, unlike 100BASE−T4, 100BASE−T2 requires only two twisted−pair cables and supports full−duplex links as well as half−duplex operation.
A station with a 100BASE−T2 interface could be connected to a half−duplex environment by linking it to a hub, or it could run in full−duplex mode when connected to another station or a switch.
A 100BASE−T2 link actually always physically operates in a full−duplex manner. After an autoconfiguration negotiation that establishes the ...