电信专业英英词典D-2（在线收听）

　　Delay - This is the wait time between to specific events, and regarding satellite communications, it is the time it takes for a signal to go from the transmission station up to orbit and through the satellite and back down to the receiving earth station (about 1/4 of a second).

　　Delete - This terms means to discard (i.e., destroy) information.

　　Delivery on-orbit - A contractual term describing a service to deliver the satellite at its intended orbital location in space.

　　Demodulation - This is the process of extracting the electrical signal (i.e., the data) from the carrier signal.

　　Demodulator - A satellite receiver circuit which extracts or "demodulates" the desired data from from the received carrier signal.

　　Deviation - The modulation level of an FM signal determined by the amount of frequency the signal is from the frequency of the main carrier signal.

　　Dial - This refers to the sending out of either pulses or tones with the intent of establishing a connection (i.e., a circuit) with another phone or modem.

　　Dialup Modem - This is a modem that is used over normal telephone lines (i.e., not DSL or cable)

　　Dial String - This is the string of characters used to contact another device over telephone lines.

　　Dial Tone - This sound signifies that a telephone is ready to receive instruction (i.e., make a call).

　　Dibit - This is group of two bits.

　　Digital - Referring to communications techniques whereby information and data are encoded as discrete elements in a binary language, as opposed to analog representation of information in variable, but continuous, wave forms.

　　DIP - This is the act of extracting particular information from a database.

　　Diplexer - This is a device which combines two transmitters onto one single transmission line.

　　Dipole - This is an antenna that is fed from the center (such as rabbit ears).

　　Disconnect - To break a connection (i.e., a circuit) so communication is no longer possible.

　　Domain - On the internet, a domain is a place to visit with your internet browser.

　　Door - This is a software program that allows BBS users to run a program while a user is simultaneously using the BBS.

　　Down - This is a general term that means that something is not currently working.

　　Downlink - The segment of a satellite circuit that extends from the satellite to the user terminal (such as, but not limited to, a television).

　　Download - This term means to receive data from another source.

　　Driver - This is a software program that provides instructions to a computer on how to communicate with peripheral devices, such as printers or modems.

　　DTE - see Data Terminal Equipment.

　　DTMF - see Dual Tone Multi-Frequency.

　　DTR - see Data Terminal Ready.

　　DTV - Stands for Digital Television.