Twisted Pair Physical Medium Dependent (TP-PMD) is an ANSI standard initiated in 1993. Working Group X3T9.5/93-223 specified TP-PMD for the transmission of FDDI data on TP cables up to a maximum distance of 100 meters.
At the physical layer, TP-PMD uses Multi Level Coding (MLC) and Multi Level Transmission (MLT-3). The TP-PMD standard provides for the use of UTP cables with 100 Ohm as well as STP cables with an impedance of
150 Ohm. TheRJ45
plugor the Sub-D plug can be used as connectors
. TP-PMD has the advantage that it builds on established standards and preserves the MAC layer. It is used in FDDI, Copper Distributed Data Interface (CDDI) and Twisted Pair Distributed Data Interface (TPDDI), among others.