IEEE 802.3 100Base-T2
A consortium of IBM and Booktree has developed 100 Mbps technology(100Base-T) on simple Category 3 UTP cable, over two pairs of wires; hence the T2 designation.
Since this technology was previously considered unfeasible, a working group was set up in the IEEE to promote the standardization of this 100 Mbit/s technology over Cat 3 cables. This topic is particularly topical in the USA, where there is a broad base of installed 10Base-T connections over such Cat-3 cables.
For transmission, a pulse amplitude modulation, the PAM5x5 method, with five different levels is used. With simultaneous transmission on two lines, 25 different signal points can thus be transmitted.