电信专业英英词典D-1_电脑电信

　dama - stands for demand-assigned multiple access. this is a way to instantaneously assign telephony channels in a transponder according to the immediate traffic demands.

　dash - this is the the character "-".

　data - this term typically refers to anything that is not a voice, and it is, according to at&t, "a representation of facts, concepts or instructions in a formalized manner, suitable for communication, interpretation or processing."

　database - this term refers to a collection of data that is catalogued in a logical way to ensure quick and reliable access.

　data carrier detect (dcd) - this is a hardware signal that indicates when a modem is online and capable of transmission.

　data communications equipment (dce) - this is a device that translates a digital signal from data terminal equipment (dte) into a form acceptable to the receiving device.

　data compression - this is when data file size is reduced by elimination unnecessary information.

　data grade circuit - this is a circuit, such as a phone line, that is capable and suitable for transmitting data.

　data link - this term describes communications paths that are used for data transmissions.

　data set - (1) according to at&t a data set is modem, but (2) according to ibm, a data set is a collection of data.

　data set ready (dsr) - this is a control signal that says that says a modem is ready to begin initial stages of transmission (i.e., configuration).

　data terminal equipment (dte) - this is equipment that only receives information (i.e., no transmission), such as a printer.

　data terminal ready (dtr) - this is another control signal that says that modems have completed their initial configuration session and are ready for transmission.

　dbs - this stands for direct broadcast satellite, and refers to service that uses satellites to broadcast multiple channels of television programming to home mounted small-dish antennas, such as those provided by directv or dish network.

　dbi - the db power relative to an isotropic source.

　dbw - the ratio of the power to one watt; it is expressed in decibels.

　dcd - see data carrier detect.

　dce - see data communications equipment.

　decibel (db) - the standard unit used to express the ratio of two power levels. in the communications field, it is used to express either a gain or loss in power after the signal has traveled between the input and output devices.

　declination - the offset angle of an antenna from the axis of its polar mount.

　decoder - also called a receiver, this is a television-top device that converts an electronically scrambled television picture into a signal viewable on the tv.

　deemphasis - reinstatement of a uniform baseband frequency response following demodulation.

　default - this is the factory setting or configuration of software or hardware.