CDDI

Short for Copper Distributed Data Interface, CDDI is officially called the Twisted-Pair Physical Medium Dependent (TP-PMD) standard and is a data transmission standard that uses either shielded twisted-pair (STP) or unshielded twisted-pair (UTP) copper wire. The standard is based on FDDI (Fiber Distributed Data Interface) which uses fiber optic lines instead of copper wires.

CDDI can be utilized for distances up to 200 meters and allows for a dual-ring capacity of 200 Mbps, unlike FDDI, which can be utilized for distances much greater than 200 meters, but only allows for a capacity of 100 Mbps. It conforms to the OSI model and is defined by the American National Standards Committee X3-T9.5. CDDI was adopted into the X3-T9.5 standard in 1994.

Also see: Network definitions