Cabletron Systems MCC-16, User Manual

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C-1
APPENDIX C
MEDIA SPECIFICATIONS
This appendix describes design and performance specifications for each
of the media types used with Token Ring.
C.1 TWISTED PAIR COPPER CABLE
Twisted pair copper cable is used for baseband data transmission. It
consists of multiple pairs of entwined solid copper wire strands that are
each encased in an insulating material within an outer protective sheath.
In contrast to unshielded twisted pair (UTP), shielded twisted pair (STP)
cable pairs are also encased in a metallic, conducting material designed to
block out intrusive outside electrical signals that can interfere with signal
traffic on the cable.
C.1.1 UTP
Lobe ports support UTP cable categories 3, 4, and 5, which are described
as follows:
• Category 3 UTP cable consists of four unshielded twisted pairs of 24
AWG solid wire for data or voice communication. It is typically used
to wire cable runs within the walls of buildings. Because it does not
meet the minimum Near-End Crosstalk (NEXT) tolerance for 16
Mbps Token Ring transmission, it is not recommended for installation.
•
Category 4 and 5 are enhanced versions of twisted pair. Both are
composed of the same wire gauge as Category 3, but demonstrate
superior performance due to improvements in design (e.g., more twists
per foot). Because of their ability to filter crosstalk and noise at 16
Mbps, they are recommended for Token Ring installation.
Table C-1 lists performance specifications for UTP cable categories 3, 4,
and 5 at Token Ring operating frequencies of 4 and 16 MHz. The values
listed include the maximum attenuation of the cables, connectors, patch
panels, and reflection losses due to impedance mismatches in the
segment.