Dell PowerEdge 4400 - Manual (Page 44)

system.
l
Keep components in their antistatic packaging until they are installed.
l Avoid wearing clothing made of wool or synthetic materials.
Electromagnetic and Radio Frequency Interference
Electromagnetic interference (EMI) and radio frequency interference (RFI) from a system can adversely affect devices such as radio and television
(TV) receivers operating near the system. Radio frequencies emanating from a system can also interfere with cordless and low-power telephones.
Conversely, RFI from high-power telephones can cause spurious characters to appear on the system's monitor screen.
RFI is defined as any EMI with a frequency above 10 kilohertz (kHz). This type of interference can travel from the system 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 Dell system meets these FCC regulations.
To reduce the possibility of EMI and RFI, follow these guidelines:
l
Operate the system only with the system cover installed.
l 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.
l Ensure that the screws on all peripheral cable connectors are securely fastened to their corresponding connectors on the back of the system.
l Always use shielded cables with metal connector shells for attaching peripherals to the system.
To prevent the possibility of RFI from a system affecting TV reception, follow these guidelines:
l Keep any TV set at least 6 ft away from the system.
l Use cable TV when possible.
l
Use a directional outdoor TV antenna.
l Attach line filters to the TV set.
l Use 75-ohm coaxial cable for the TV set rather than twin-lead antenna wire.
l
If interference occurs, rotate the system 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:
l Monitors
l TV sets
l
Printers
l Telephones with real bells
l 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 even after withstanding a minimum of six consecutively executed shock pulses in the positive and negative x, y, and z axes (one
pulse on each side of the system). Each shock pulse can measure up to 41 gravities (G) for up to 2 milliseconds (ms). In storage, the system can
withstand shock pulses of 71 G for 2 ms.
Excessive vibration can cause the same problems as mentioned earlier for shock, as well as causing 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
Systems are especially sensitive to variations in voltage supplied by the AC power source. Over-voltage, 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: