Cisco Systems UBR7100E manual Plant Wiring Guidelines, Interference Considerations

Chapter 2 Preparing for Installation

Site Requirement Guidelines

Note The Cisco uBR7100 series router installation must comply with all applicable codes and is approved for use with copper conductors only. If installing the router in a central office environment that requires Telcordia grounding, the ground bond fastening hardware should be of compatible material and preclude loosening, deterioration, and electrochemical corrosion of hardware and joined material. Attachment of the chassis ground to a central office or other interior ground system should be made with a minimum 6-AWG, copper ground conductor.

To satisfy Telcordia grounding requirements, the chassis provides two threaded chassis grounding receptacles, located on the sides near the rear of the chassis, which are intended to be bonded directly to the central offices or other interior ground system. The chassis ground requires 3.5 mm screws, which are included. See “Attaching the System Ground Connection” section on page 3-5for instructions on attaching the system ground.

Plant Wiring Guidelines

Following are guidelines for setting up the plant wiring and cabling at your site. When planning the location of the new system, consider the distance limitations for signaling, EMC, and connector compatibility, as described in the following sections.

Interference Considerations

When wires are run for any significant distance in an electromagnetic field, interference can occur between the field and the signals on the wires. This fact has two implications for the construction of plant wiring:

•Bad wiring practice can result in radio interference emanating from the plant wiring.

•Strong electromagnetic interference (EMI), especially when it is caused by lightning or radio transmitters, can destroy the signal drivers and receivers in the router, and can even create an electrical hazard by conducting power surges through lines and into equipment. (Review the safety warnings in the “Electrical Equipment Guidelines” section on page 2-3.)

Note To predict and remedy strong EMI, you may also need to consult experts in radio frequency interference (RFI).

If you use twisted-pair cable in your plant wiring with a good distribution of grounding conductors, the plant wiring is unlikely to emit radio interference. If you exceed the recommended distances, use a high-quality twisted-pair cable with one ground conductor for each data signal when applicable.

If wires exceed recommended distances, or if wires pass between buildings, give special consideration to the effect of a lightning strike in your vicinity. The electromagnetic pulse caused by lightning or other high-energy phenomena can easily couple enough energy into unshielded conductors to destroy electronic devices. If you have had problems of this sort in the past, you may want to consult experts in electrical surge suppression and shielding.

Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide

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