Any of several fast ethernet 100 mbps csma/cd standards for twisted pair cables, including: 100BaseTx (100 Mbps over two-pair cat5 or better cable), 100BaseT4 (100 Mbps over four-pair cat3 or better cable), 100BaseT2 (in committee; 100 Mbps over two-pair Cat3 or better cable). All are standards (or planned standards) under ieee 802.3.