Glossary 111

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DSR signal: This signal tells the personal computer whether the modem is ready for communication.

DTR signal: This signal tells the modem whether the personal computer is ready for communication.

duplex: The method used to transmit data in both directions between two devices. Synonymous with full duplex. See also half duplex, full duplex.

echo: Displays keyboard entry on the computer terminal.

EIA: Electronic Industries Association is a manufacturers group that sets standards for data communications equipment.

error control: Detection of errors in data communication. Requests retransmission of data in which errors were found.

Error control: Detection of errors in data communication. Requests retransmission of data in which errors were found.

escape: 1) To cancel the task currently in progress. 2) A code (ASCII code 27, generated by the Esc key) telling the computer that what follows are commands, not data. Used with peripheral devices such as printers and modems.

Escape control: This code is used to return to the command state without disconnecting the line when the internal modem is online.

FIFO: First-In/First-Out means the first data that enters a buffer is the first to be retrieved.

Fallback: Reduction of a modem’s speed. If the remote modem cannot communicate as fast as the local modem, the local modem will reduce its speed.

firmware: A set of instructions built into a chip to control its activities.