Information Technology Reference
In-Depth Information
FIGURE 3.4
A typical workstation outlet for Type 2 cable. (Courtesy of Hubbell Premise Wiring, Inc.)
Several other variations of IBM cabling system wire may be found, the most
common being Type 3, Type 6, and Type 9 cable. Type 6 and Type 9 are 26-gauge
nonplenum and plenum versions of Type 1 cable. Type 3 wire is 105-ohm, 24-gauge,
unshielded, twisted 4-pair cable that meets IBM's specifications. It is available in
plenum and nonplenum insulation and is similar but not identical to Category 3
cable. When Type 3 wire is used as station cable, a special adapter cable (called a
media filter
) must be used to match the 105-ohm cable to 150-ohm device inter-
faces, such as Token-Ring interfaces. Some newer Token-Ring interfaces also have a
105-ohm modular jack, which eliminates the need for the media filter. Similar media
filters may be used with 100-ohm Category 3, 4, 5 cable.
Note:
Older media filters
may support only 4 Mbps Token-Ring and will fail when used with 16 Mbps rings.
