A device that helps linked computers synchronize data transmission and provide error correction. digital video disc (DVD) A disk that can hold seven to twelve times the amount of data on a CD-ROM, transfer data faster than the fastest CD-ROM today, and record data at your computer.

A system component which allows communication over digital access facilities with a remotely located system connected to the public network over analog facilities. Converts incoming digital datastream containing PCM-encoded modem waveform into actual data contained in waveform at a data rate transmitted by far-end modem; performs inverse function for outgoing data stream. See also Modem.

A system component which allows modem users to communicate over digital access facilities. They work by converting the PCM-encoded digital data streams sent by analogue modem users into their original analogue waveform.

A communications device that acts as the intermediary between a digital device such as a computer or terminal and a digital communications channel, such as a high-speed network line, an ISDN circuit, or a cable TV system. Although a digital modem supports standard (analog) modem protocols, it is not a "typical" modem in the sense of being a device whose primary function is to modulate (convert digital to analog) before transmission and demodulate (convert analog to digital) after transmission. It uses advanced digital modulation techniques for changing data frames into a format suitable for transmission over a digital line. A 56 Kbps modem. Such a modem is not purely digital but does eliminate the tra-ditional digital-to-analog conversion for downstream transmissions-that is, transmissions moving from the Internet to the end user. A 56 Kbps modem is also digital in that it requires a digital connection, such as T1, between the telephone company and the user's Internet Service Provider (ISP) in order to achieve its highest speed.

Modem that sends and receives data and information to and from a digital telephone line such as ISDN or DSL. 9.28 Digital revolution, 1.2-4, 1.9