Rochester, New Hampshire-based Cabletron Systems Inc says that its joint proposal with National Semiconductor Corp, Santa Clara for a 100Base-T standard for transmitting 100Mbps Fibre Distributed Data Interface signals over both shielded and data grade unshielded twisted pair cabling has been accepted by the American National Standards Committee’s X3T9.5 FDDI Physical Media Dependent Work Group as one of two proposals for developing the evolving FDDI standard. The 100Base-T proposal from NatSemi and Cabletron differs from the MLT-3 proposal under review by ANSI in that it incorporates a low-cost method for bringing the FDDI system to the desktop over copper cabling. The technique, called pre-compensation, shapes the signal at the transmission end of the cable to compensate for effects caused by the media. It uses FDDI’s existing Non Return to Zero Inverted standard two-level signal encoding technique to give greater noise immunity.
