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USRobotics V.34 User Manual

Page 216

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COURIER HIGH SPEED MODEMS

Glossary J-7

Error Control

Various techniques which check the reliability of characters
(parity) or blocks of data. V.42, MNP and HST error control
protocols use error detection (CRC) and retransmission of
errored frames (ARQ).

Facsimile

A method for transmitting the image on a printed page from
one point to another. Commonly referred to as Fax.

Fax Mode

The mode in which the fax modem is capable of sending and
receiving files in a facsimile format.

Flash ROM

Read Only Memory that can be erased and reprogrammed.

Flow Control

A mechanism that compensates for differences in the flow of
data input to and output from a modem or other device.

Frame

A data communications term for a block of data with header
and trailer information attached. The added information usu-
ally includes a frame number, block size data, error-check
codes, and Start/End indicators.

Full Duplex

Signal flow in both directions at the same time. In micro-
computer communications, may refer to the suppression of the
online Local Echo.

Half Duplex

Signal flow in both directions, but only one way at a time. In
microcomputer communications, may refer to activation of the
online Local Echo, which causes the modem to send a copy of
the transmitted data to the screen of the sending computer.