Assessments - 2, GPA: 4
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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. C-. Dell PowerEdge 4350 Systems User.s Guid. To reduce the possibility of EMI and RFI, follow these guidelines. . Operate the system only with the system 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 system. . 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. . Keep any TV set at least 6 ft away from the 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 system or the TV set 9. degrees.. 0DJQHWLV. Because they store data magnetically, diskettes and hard-disk drives are extremely. susceptible to the effects of magnetism. Diskettes should never be stored near mag. netic sources such as the following. . Monitor. . TV set. . Printer. . Telephones with real bell. . Fluorescent lights. 6KRFNDQG9LEUDWLR. Excessive shock can damage the function, external appearance, and physical struc. ture 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 50 gravities (G) for up to . milliseconds (ms). In storage, the sys. tem can withstand shock pulses of 92 G for 2 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. Maintaining the Syste. C-. Each Dell system, when operating, is designed to withstand 0.25 G (half-sine wave) at. a sweep of 3 to 20. hertz (Hz) for 15 minutes. In storage, the system can withstand. 0.5 G at 3 to 200 Hz for 15 minutes. 3RZHU6RXUFH,QWHUUXSWLRQ. 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 prob. lems, 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,. .Power Protection Devices.. . 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 machine. . Air conditioner. . Vacuum cleaner. . Space heater. . Power tools. . Teletype machine. . Adding machine. . Laser printer. . Facsimile machine. . Any other motorized equipmen. Besides these appliances, the greatest threat to a system.s supply of power are. surges or blackouts caused by electrical storms. Whenever possible, turn off the sys. tem and any peripherals and unplug them from their power sources during. thunderstorms.. If a blackout occurs.even a temporary one.while the system is turned on, turn off. the system immediately and disconnect it from its power source. Leaving the system. on may cause problems when the power is restored; all other appliances left on in the. area can create large voltage spikes that can damage the system. C-. Dell PowerEdge 4350 Systems User.s Guid. 3RZHU3URWHFWLRQ'HYLFH. A number of devices are available that protect against power problems, such as. power surges, transients, and power failures. The following subsections describe. some of these devices. 6XUJH3URWHFWRU. Surge protectors are available in a variety of types and usually provide a level of pro. tection commensurate with the cost of the device. Surge protectors prevent voltage. spikes, such as those caused during an electrical storm, from entering a system. through the AC power source. Surge protectors, however, do not offer protection. against brownouts, which occur when the voltage drops more than 20 percent below. the normal AC line voltage level. /LQH&RQGLWLRQHU. Line conditioners go beyond the overvoltage protection of surge protectors. Line con. ditioners keep a system.s AC power source voltage at a fairly constant level and,. therefore, can handle brownouts. Bec...