scope:

General

This Recommendation describes a lossless data compression procedure for use with V-series data circuit-terminating equipment (DCEs).

The principal characteristics of the data compression procedure are:

a) a compression procedure based on an algorithm that encodes strings of characters input from data terminal equipment (DTE) as binary codes of variable length;

b) a decoding procedure that recovers the strings of characters from received binary codes of variable length;

c) a string-building mechanism that rapidly extends existing strings;

d) an automatically invoked transparent mode of operation when uncompressible data are detected.

Annex B describes the implementation of this data compression procedure in packet networks.

A summary of the set of parameters used in this Recommendation is given in clause 8.

Clause I.7 summarizes the main differences between the algorithms of ITU-T V.44 and V.42 bis.

This Recommendation contains examples for illustrative purposes; in any case in which an example appears to contradict the normative text, the normative text shall take precedence.