CDDI is also known as TPDDI (Twisted-pair Distributed Data Interface). CDDI employs Cat 5 UTP as an inexpensive means of connecting workstations and peripherals to FDDI fiber optic backbone LANs. A transmission rates up to 100 Mbps may be achieved in this scheme.
The maximum allowable distance between hub and the device is not specified categorically but generally it is kept less than 20 meters. Cat 3 UTP often is used for 4 Mbps token ring LANs, cat4 UTP has a bandwidth of 20 MHz and commonly is used for 16 Mbps token ring LANs.