copper distributed data interface (FDDI) (CDDI)

Copper Distributed Data Interface (CDDI) is the implementation ofFDDI transmission technology with TP cables, therefore this approach is sometimes also referred to as Twisted Pair Distributed Data Interface( TPDDI).

CDDI offers itself as a cost-effective alternative to the considerably more expensive fiber optic cabling in the front-end area. Both shielded 100-ohm four- wire cables( STP) in Type 1A quality according to the IBM cabling systemIVS and unshielded cables( UTP) according to EIA/ TIA 586 Category 5 can be used. Distances of up to 150 m to the FDDI node can be bridged with the STP cables; up to 50 m with UTP cables. The familiar RJ45 connector is used as the plug technology.

CDDI uses PR4 coding, which stands for Partial Response Class 4, as the coding method. With CDDI implementations, only the connection of SAS stations in the terminal area is possible. CDDI is not standard-compliant.