110 Glossary

D

DAA: Data Access Arrangement is a circuit that isolates a device

 

 

from phone lines.

 

data: Information that a computer can process. The word “data” is

 

actually plural for “datum,” meaning a single piece of

 

information.

 

data bits: A data communications parameter controlling the

 

number of bits used to represent a character. If data bits = 7, the

 

computer can generate 128 unique characters, if data bits = 8, the

 

computer can generate 256 unique characters.

 

DCE (Data Communications Equipment or Data Circuit-

 

terminating Equipment): A device that establishes, maintains and

 

terminates a session on a network. It may also convert signals for

 

transmission. It is typically the modem.

 

DCD signal: This signal tells the personal computer whether the

 

modem is receiving the carrier from the opposite station

 

DTE (Data Terminating Equipment): A communications device

 

that is the source or destination of signals on a network. It is

 

typically a terminal or computer.

 

dial tone: The tone that is heard from the handset when it is picked

 

up

 

dial mode: Dial mode covers pulse dial and tone dial. Pulse dial

 

means turning the dial or pressing the buttons to send pulse

 

signals to connect to the called party. Tone dial means pressing

 

the button to send tone signals to connect the modem to the called

 

party.

 

download: 1) To receive a file from another computer through a

 

modem. 2) To transmit font data from the computer to a printer.

 

See also upload.

 

DSP: A digital signal processor is a chip designed for real-time

 

applications. DSP techniques are used in PC processors as well as

 

media engines. For example, some high-end notebooks use a

 

DSP chip to provide Sound Blaster emulation for the internal

 

modem as well.