Magnetism, Power source interruptions – Cisco 4490 User Manual
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Chapter 5 Maintaining the Cisco Global Site Selector 4490
Maintaining Your Site Environment
5-6
Cisco Global Site Selector 4490 Hardware Installation Guide
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Magnetism
Because they store data magnetically, hard disk drives are extremely susceptible
to the effects of magnetism. Hard disk drives should never be stored near magnetic
sources such as the following:
•
Monitors
•
TV sets
•
Printers
•
Telephones with real bells
•
Fluorescent lights
Power Source Interruptions
Systems are especially sensitive to variations in voltage supplied by the AC power
source. Overvoltage, undervoltage, and transients (or spikes) can erase data from
memory or even cause components to fail. To protect against these types of
problems, power cables should always be properly grounded and one or both of
the following methods should be used:
•
Use one of the power protection devices described in the
section.
•
Place the system on a dedicated power circuit (rather than sharing a circuit
with other heavy electrical equipment). In general, do not allow the system to
share a circuit with any of the following:
–
Copier machines
–
Air conditioners
–
Vacuum cleaners
–
Space heaters
–
Power tools
–
Teletype machines