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Maintaining the CSACS-1121, Cisco SNS-3400 Series, and Cisco SNS-3500 series Appliances
Maintaining the CSACS-1121 Series Appliance
Altitude
Operating an appliance at high altitudes (low atmospheric pressure) reduces the efficiency of forced and convection
cooling which can result in electrical problems related to arcing and corona effects. This condition can also cause sealed
components with internal pressure, such as electrolytic capacitors, to fail or perform at reduced efficiency.
Electrostatic Discharge
Electrostatic discharge (ESD) results from the buildup of static electricity on the human body and certain other objects.
This static electricity is often produced by simple movements, such as walking across a carpet.
ESD is a discharge of a static electrical charge that occurs when a person whose body contains such a charge touches
a component in the appliance. This static discharge can cause components, especially ICs, to fail. ESD is a problem
particularly in dry environments where the relative humidity is below 50 percent.
To reduce the effects of ESD, you should observe the following guidelines:
Wear a grounding wrist strap. If a grounding wrist strap is unavailable, touch an unpainted metal surface on the
appliance chassis periodically to neutralize any static charge.
Keep components in their anti-static packaging until they are installed.
Avoid wearing clothing made of wool or synthetic materials.
Electromagnetic and Radio Frequency Interference
Electromagnetic interference (EMI) and radio frequency interference (RFI) from an appliance can adversely affect devices
such as radio and television receivers operating near the appliance. Radio frequencies emanating from an appliance can
also interfere with cordless and low-power telephones.
RFI is defined as any EMI with a frequency above 10 kHz. This type of interference can travel from the appliance 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 emitted by
computing equipment. Each appliance meets these FCC regulations.
To reduce the possibility of EMI and RFI, follow these guidelines:
Operate the appliance only with the appliance cover installed.
Ensure that the screws on all peripheral cable connectors are securely fastened to their corresponding connectors
on the back of the appliance.
Always use shielded cables with metal connector shells for attaching peripherals to the appliance.
Magnetism
Hard disk drives are susceptible to the effects of magnetism as they store data magnetically. Hard disk drives should
never be stored near magnetic sources such as:
Monitors
Printers
Telephones with real bells
Fluorescent lights
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