Glossary

error control

A variety of techniques that check the reliability of characters (parity) or blocks of data. V.42 and MNP error-control protocols use error detection (CRC) and retransmission of flawed frames (ARQ).

facsimile

A method for transmitting the image on a page from one point to another. This is commonly referred to as fax.

fax mode

The mode in which the faxmodem is capable of sending and receiving files in a facsimile format. See definitions for V.17, V.27ter, V.29.

flow control

A mechanism that compensates for differences in the flow of data into and out of a modem or other device. See commands &Hn, &In, &Rn.

frame

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

full duplex

These signals will flow in both directions at the same time. In microcomputer communications, may refer to the suppression of the on- line local echo.

half duplex

These signals will 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.

Hz

Hertz is a frequency measurement unit used internationally to indicate one cycle per second.

46 56K Voice Faxmodem Internal - User’s Guide

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3Com 1.024.1644-00 manual Glossary Error control, Facsimile, Fax mode, Flow control, Frame, Full duplex, Half duplex