Cabletron Systems 100BASE-FX, Руководство по кабельной продукции

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Cabling Types 9-5
Token Ring Media
Type 9
Type 9 cable is similar in construction to Type 6 cable, and is intended to be used
for the same purposes. The center strands of a Type 9 cable are made of either
solid or stranded 26 AWG conductors.
Unshielded Twisted Pair (UTP)
Unshielded Twisted Pair cabling (referred to here as UTP) is commonly made up
of two or four pairs of 22, 24, or 26 AWG unshielded copper solid or stranded
wires. These pairs of wires are twisted together throughout the length of the
cable. These twisted pairs of wire within the UTP cable are broken up into
transmit and receive pairs. The UTP cable used in network installations is the
same type of cable used in the installation of telephone lines within buildings.
UTP cabling is differentiated by the quality category of the cable itself, which is an
indicator of the type and quality of wire used and the number of times the wires
are twisted around each other per foot. The categories range from Category 1 to
Category 5, with Category 5 cabling being of the highest quality.
The wires that make up a length of UTP cable are numbered and color coded.
These color codes allow the installer of the networking cable to determine which
wires are connected to the pins of the RJ45 ports or patch panels. The numbering
of the wires in USOC
standard cables is based on the color of the insulating jacket
that surrounds the core of each wire.
Each jacket will have an overall color: brown, blue, orange, green, or white. In a
4-pair UTP cable (the typical UTP used in networking installations) there will be
one wire each of brown, blue, green, and orange, and four wires whose overall
color is white. The white wires will be distinguished from one another by
periodically placed (usually within 1/2 inch of one another) rings of the other
four colors.
Wires with a unique base color are identified by that base color: blue, brown,
green, or orange. Those wires that are primarily white are identified as
white/<color>, where <color> indicates the color of the rings of the other four
colors in the white insulator.
The association of pairs of wire within the UTP cable jacket are decided by the
specifications to which the cable is built. There are two main specifications in use
around the world for the production of UTP cabling: EIA/TIA 568 and USOC.
The two wiring standards are different from one another in the way that the wires
are associated with one another throughout the cable.
The arrangement of the wires in the two specifications does not affect the
usefulness of the resultant cables for Token Ring networking. The arrangement of
the wires and pairs in the EIA/TIA and USOC specifications is discussed in the
UTP Cable
portion of the Connector Types section of this chapter.