Network Router User's Manual

2-4
Cisco MGX 8260 Hardware Installation Guide
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Chapter 2 Safety and Compliance
Equipment Location and Environmental Requirements
Preventing Interference
When wires are run for any significant distance in an electromagnetic field, induced interference can
distort the signals on the wires. The potential presence of interference has two implications for the
construction of plant wiring:
• Poor wiring practice can result in radio interference.
• Strong electromagnetic interference (EMI), especially that caused by lightning, radio transmitters
or induction start motors, can destroy the signal drivers and receivers in servers and controllers. EMI
can even create an electrical hazard by conducting power line surges. For more information on the
effects of EMI, review the safety guidelines in the “Preventing Electrostatic Discharge Damage”
section on page 2-3.
Follow these guidelines to reduce the possibility of extraneous interference and damage from EMI
pulses:
• Use twisted-pair cable in your plant wiring with good earthing distribution. If you must exceed the
recommended wiring distances, use a high-quality twisted-pair cable with one ground conductor for
each data signal.
Note Shielded twisted pair (STP) cabling must be used from the rear of the MGX 8260 to the
demarcation point for all DS1 spans. Coaxial cable must be used from the rear of the
MGX 8260 to the demarcation point for all DS3 spans.
• If wires exceed recommended distances or pass between buildings, consider 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, consider consulting experts in electrical
surge suppression and shielding.
• Use dedicated power circuits to feed each Cisco MGX 8260 node. If possible, avoid tapping master
AC power feeds that also service high-current, motor-driven devices such as air conditioners or
elevators.
Note Refer to the documentation shipped with the Cisco MGX 8260, as well as published
interface and wiring standards for detailed requirements.
Note To predict and remedy strong EMI, you might also need to consult experts in radio frequency
interference (RFI).
Equipment Location and Environmental Requirements
Proper location of the MGX 8260 chassis and careful layout of the equipment rack is essential for
successful operation. Equipment placed too close together or inadequately ventilated can cause system
overtemperature conditions. In addition, chassis panels made inaccessible by poor equipment placement
can make system maintenance difficult. For environmental information pertaining to temperature,
humidity, and altitude, refer to Table B-3 on page B-2.