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INTRODUCTION
1.4
TECHNOLOGY OVERVIEW
1.4.1
100 Megabit/Second FDDI Over Copper
The migration of FDDI fiber optic technology to twisted pair
copper wire began with the desire to utilize inexpensive, and
previously installed twisted pair cable as a replacement for more
expensive vendor-specific media.
There are many benefits to be gained from operating FDDI
technology on twisted pair cable: increased bandwidth,
elimination of rewiring costs, reduced cost of new installations,
and simpler and less expensive transceivers.
In pursuit of these goals, Cabletron Systems is participating in the
standards process with the American National Standards Institute
(ANSI), creating a draft standard for the transmission of 100 Mb/s
FDDI data over twisted pair copper wire. The new standards,
Twisted Pair - Physical Media Dependent (
TP-PMD
) and Shielded
Twisted Pair - Physical Media Dependent (
STP-PMD
) define the
minimum performance requirements for both shielded and
unshielded twisted pair cable. The guidelines for the new standard
are set forth below:
•
Transmit distance of 100 meters for both UTP and STP cable.
•
The same Bit Error Rate as FDDI over fiber cable (2 x 10
-1
).
•
FCC Class A (commercial) certification.
•
European EN55022 Class A (commercial) certification.
•
UTP - Category 5 cable (as specified in EIA/TIA TSB-36).
•
STP - Type 1, individually and overall shielded, 150 ohm cable.
