100Base-T4 Operation; 100Base-Fx Operation - 3Com 10/100BASE-T4 User Manual

100BASE-T4 Operation

100BASE-T4 is the IEEE 802.3 specification for Ethernet
signaling for 100 Mbps over four pairs of Category 3 or better
UTP cable.This physical layer standard was specifically defined
to allow 100BASE-T to be deployed over the large installed
base of Category 3 voice-grade UTP.
100BASE-T4 uses four pairs of Category 3, 4, or 5 UTP cable, at
distances of up to 100 meters. Transmission requires four pairs
of cable to lower emissions and meet FCC requirements. You
must have four pairs of UTP available for each node to run
100BASE-T4.

100BASE-FX Operation

100BASE-FX is the IEEE 802.3 specification for 100 Mbps Ethernet
signaling over two strands of fiber cabling. 100BASE-FX is used
for transmissions over extended distances (up to 2 kilometers
[1.24 miles] between nodes), downlinks, and backbones, and is
especially useful in any environment subject to electrical
interference.
100BASE-T Standard A-5