Altitude Requirements; Dust And Particulate Requirements; Minimizing Electromagnetic And Radio Frequency Interference - Cisco Nexus 9336PQ Hardware Installation Manual

Altitude Requirements

Altitude Requirements
If you operate a switch at a high altitude (low pressure), the efficiency of forced and convection cooling is
reduced and can result in electrical problems that are related to arcing and corona effects. This condition can
also cause sealed components with internal pressure, such as electrolytic capacitors, to fail or to perform at a
reduced efficiency. This switch is rated to operate at altitudes from 0 to 13,123 feet (0 to 4,000 meters).

Dust and Particulate Requirements

Exhaust fans cool power supplies and system fans cool switches by drawing in air and exhausting air out
through various openings in the chassis. However, fans also ingest dust and other particles, causing contaminant
buildup in the switch and increased internal chassis temperature. A clean operating environment can greatly
reduce the negative effects of dust and other particles, which act as insulators and interfere with the mechanical
components in the switch.
In addition to regular cleaning, follow these precautions to avoid contamination of your switch:
• Do not permit smoking near the switch.
• Do not permit food or drink near the switch.

Minimizing Electromagnetic and Radio Frequency Interference

Electromagnetic interference (EMI) and radio frequency interference (RFI) from the switch can adversely
affect other devices such as radio and television (TV) receivers operating near the switch. Radio frequencies
that emanate from the switch can also interfere with cordless and low-power telephones. Conversely, RFI
from high-power telephones can cause spurious characters to appear on the switch monitor.
RFI is defined as any EMI with a frequency above 10 kHz. This type of interference can travel from the switch
to other devices through the power cable and power source or through the air as transmitted radio waves. The
Federal Communications Commission (FCC) publishes specific regulations to limit the amount of EMI and
RFI that can be emitted by computing equipment. Each switch meets these FCC regulations.
To reduce the possibility of EMI and RFI, follow these guidelines:
• Cover all open expansion slots with a blank filler plate.
• Always use shielded cables with metal connector shells for attaching peripherals to the switch.
When wires are run for any significant distance in an electromagnetic field, interference can occur between
the field and the signals on the wires with the following implications:
• Bad wiring can result in radio interference emanating from the plant wiring.
• Strong EMI, especially when it is caused by lightning or radio transmitters, can destroy the signal drivers
Cisco Nexus 9336PQ ACI-Mode Switch Hardware Installation Guide
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and receivers in the chassis and even create an electrical hazard by conducting power surges through
lines into equipment.
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