Dell Precision 610 User Manual
Page 111
other devices through the AC 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 Dell system meets these FCC regulations.
To reduce the possibility of EMI and RFI, follow these guidelines:
Operate the system only with the computer cover installed.
Ensure that all expansion slots are covered either by a card-mounting bracket or by a metal filler bracket and that all drive
bays have a drive and/or a metal insert installed. These brackets and metal inserts are available from Dell.
Ensure that the screws on all peripheral cable connectors are securely fastened to their corresponding connectors on the
back of the computer.
Always use shielded cables with metal connector shells for attaching peripherals to the computer.
To prevent the possibility of RFI from a computer affecting TV reception, follow these guidelines:
Keep any TV set at least 6 ft away from the computer system.
Use cable TV when possible.
Use a directional outdoor TV antenna.
Attach line filters to the TV set.
Use 75-ohm coaxial cable for the TV set rather than twin-lead antenna wire.
If interference occurs, rotate the computer or the TV set 90 degrees.
Magnetism
Because they store data magnetically, diskettes and hard-disk drives are extremely susceptible to the effects of magnetism.
Diskettes should never be stored near magnetic sources such as the following:
Monitors
TV sets
Printers
Telephones with real bells
Fluorescent lights
Shock and Vibration
Excessive shock can damage the function, external appearance, and physical structure of a system. Each Dell system has been
designed to operate properly after withstanding a minimum of six consecutively executed shock pulses in the positive and negative
x, y, and z axes. Each shock pulse can measure up to 50 gravities (G) (half-sine wave) for up to 2 milliseconds (ms). In storage,
the system can withstand shock pulses of 110 G (half-sine wave) for 2 ms or 27 G (square wave) for 15 ms.
Excessive vibration can cause the same problems as mentioned earlier for shock, as well as cause components to become loose
in their sockets or connectors. Systems can be subject to significant vibration when being transported by vehicle or when operated
in an environment with machinery that causes vibration.
Each Dell system, when operating, is designed to withstand 0.25 G (half-sine wave) at a sweep of 3 to 200 hertz (Hz) for 30
minutes. In storage, the system can withstand 0.5 G at 3 to 200 Hz for 30 minutes.
Power Source Interruptions
Computer 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 following section, "
".
Place the system on a dedicated power circuit (rather than having it share a circuit with other heavy electrical equipment). In
general, do not allow the system to share a circuit with any of the following:
- Kitchen appliances