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  CommServ > Infrastructure > Standards > History > Physical Components
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The major underground cables between manholes are located in the major north-south and east-west axes of campus and referred to as backbone cables.
The large 3800 twisted pair, 1800 pair, and 1100 pair cables in these axes make-up the telephone backbone cable route. The coaxial cables that appear in these routes also function as backbones for the broadband and cable television systems. These backbone cables use a branching tree topology.

It is noted that the broadband coaxial network was shut-down in June of 1999 and that only the CATV coaxial backbone is currently supported along with the telephone and fiber cable plants.

The underground fiber cables on campus are not configured using a backbone (and feeder) configuration. All underground fiber cables are placed in point-to-point (entrance-to-entrance) configurations.

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Twisted pair and coaxial cables which branch off of the backbone cables and run on smaller north-south and east-west axes are referred to as feeder cables. The twisted pair telephone feeder cables distribute the capacity of the larger backbone cables into smaller cables which are attached to building entrance cables. The coaxial cables extend broadband and cable television services into routes accessed by building attachment cable. The designation of "subfeeder" cables is sometimes used to further distinguish branching feeder cables.

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Twisted pair and coaxial cables which connect the feeder cables to building main terminals are referred to as (building) entrance cables. The size (number of pairs) of a twisted pair entrance cable determines the number of dedicated twisted pair circuits available to the building. Coaxial entrance cables extend the same capacity for broadband and cable television as is available at any other building or coaxial cable attachment. Again, fiber cables are entrance-to-entrance and do not follow the backbone, feeder, and entrance cable designations.

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Once entrance cables are terminated at a building's main terminal, distribution of service is accomplished by riser and lateral cables. Risers are those cables which connect between floors (vertically) in a building to distribute services to each floor. Twisted pair riser cables are configured in two ways. One configuration provides the identical cable pair counts to each floor using multiple appearances. A second configuration provides differentiated counts at each floor. Both configurations may be achieved by use of a single cable with individual floor splices and drops, or by dedicated individual cables to each floor.

Coaxial riser cables are configured similarly to backbone or feeder cables in that all service is available at all floors by a single cable. The single cable appearance may be configured as drops or as a dedicated cable from the main terminal to each floor.

Fiber riser cables are placed as point-to-point cables from floor to floor. Dedicated fiber strands to each floor or sub-terminal is accomplished by patching of strands between main and floor fiber cable segment terminations, as required. Logically, this patching can make fiber distribution appear as point-to-point or drop and insert configurations.

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In single story buildings and within each floor of a multiple story building, cables placed between wiring closets on a common floor are referred to as lateral distribution cables. Twisted pair cables placed in laterals function identically to riser distribution cables. The same count or different counts may appear at different sub-terminals on the same floor.

Coaxial lateral cables function identically to riser cables, providing all services at all locations.

Fiber lateral cables function identically to riser cables, providing patching arrangements for point-to-point or drop and insert configurations.

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Jumper cables are cables which interconnect the individual components of a specific circuit. Cables which are placed between the wallplate and the workstation terminal or personal computer are referred to as jumper cables. Similarly, cables which are placed in sub-terminals to connect a workstation cable to a wiring hub or lateral cable termination are also called jumpers. For a unique telephone number, jumpers are placed at the switch room distribution frame to connect the switch to a wire pair in the outside cable plant, at a building main terminal to connect a pair in the entrance cable to a pair in the riser or lateral distribution cable, at the sub-terminal to connect the lateral or riser pair to a workstation cable, and at the workstation location to connect the workstation to the wall plate.

Coaxial cable jumpers may connect a tap or splitter to an individual workstation.

Fiber jumpers are used to "patch" one fiber strand to another or a fiber strand to a piece of equipment.

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Workstation cables are those which are placed between a workstation wallplate and the supporting subterminal.


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Last modified: 10/19/2007