|  | 8.5 | Planning Structured Cabling: Horizontal and Backbone Cabling
| 8.5.7 | Maximum distances for backbone cabling

As you have already learned, the maximum distances for cabling runs varies from one type of cable to another. For backbone cabling, the maximum distance for cabling runs can also be impacted by how the backbone cabling is to be used. To understand what this means, assume that a decision has been made to use single-mode fiber-optic cable for the backbone cabling. If the networking media is to be used to connect the HCC to the MCC, as described above, then the maximum distance for the backbone cabling run would be 3,000 m.

At times the maximum distance of 3000m for the backbone cabling run must be split between two sections. This occurs when the back bone cabling is to be used to connect the HCC to an ICC and the ICC to the MCC. When this occurs, the maximum distance for the backbone cabling run between the HCC and the ICC is 500 m. The maximum distance for the backbone cabling run between the ICC and the MCC is 2,500 m.

The Figure lists TIA/EIA-568-A specifications for maximum distances for backbone cabling runs for each type of networking media.

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