ITU-T V.22 BIS PDF

Introduction

These modems are intended for use on connections on the GSTN and on point-to-point 2-wire leased telephonetype circuits (see Note). The principal characteristics of these modems are as follows:

a) duplex mode of operation on the GSTN and point-to-point leased circuits,

b) channel separation by frequency division,

c) quadrature amplitude modulation for each channel with synchronous line transmission at 600 baud (nominal),

d) inclusion of a scrambler,

e) inclusion of an adaptive equalizer and a compromise equalizer,

f) inclusion of test facilities,

g) data signalling rates of:

2400 bit/s synchronous,

2400 bit/s start-stop,

1200 bit/s synchronous,

1200 bit/s start-stop,

h) it is compatible with a V.22 modem operating in Modes i) or ii) at the 1200 bit/s signalling rate and includes automatic bit rate recognition.

Note - In certain countries the use of such modems over the GSTN may not be allowed.