Dust And Particulate Requirements; Minimizing Electromagnetic And Radio Frequency Interference - Cisco Nexus 7702 Hardware Installation Manual

Dust and Particulate Requirements

reduced efficiency. This switch is rated to operate at altitudes from –500 to 13,123 feet (–152 to 4,000 meters).
You can store the switch at altitudes of –1,000 to 30,000 feet (–305 to 9,144 meters).
Dust and Particulate Requirements
Exhaust fans cool power supplies and system fan trays 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.
If you are using this switch in a nonclean environment, you can order and install an optional air filter.
Note
This air filter requires that you also order the optional front door for the chassis.
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 like 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 metal filler.
• 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 and cause 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 7702 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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