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v32biss.txt
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INTERNATIONAL TELECOMMUNICATION UNION
ITU-T RECOMMENDATION SUMMARY
Rec. No. : V.32 bis
Title : A duplex modem operating at data signalling rates of up to
14 400 bit/s for use on the general switched telephone network
and on leased point-to-point 2-wire telephone-type circuits
Study Group : XVII - Data Transmission over the Telephone Network
Version : New
Date of adoption : 1991
Notes :
Recommendation V.32 bis presents a modem which is intended for use on
connections on general switched telephone networks (GSTNs) and on
point-to-point 2-wire leased telephone-type circuits. The principal
characteristics of the modem are as follows:
a) duplex mode of operation on GSTN and point-to-point
2-wire leased circuits;
b) channel separation by echo cancellation techniques;
c) quadrature amplitude modulation for each channel with
synchronous line transmission at 2400 symbols/s;
d) the following synchronous data signalling rates shall be
implemented in the modem:
- 14 400 bit/s trellis coded,
- 12 000 bit/s trellis coded,
- 9600 bit/s trellis coded,
- 7200 bit/s trellis coded,
- 4800 bit/s uncoded;
e) compatibility with Recommendation V.32 modems at 9600 and
4800 bit/s;
f) exchange of rate sequences during start-up to establish the
data signalling rate;
g) a procedure to change the data signalling rate without
retraining.
Note 1 - On international GSTN connections that utilize circuits that
are in accord with Recommendation G.235 (16-channel terminal
equipments), it may be necessary to employ a greater degree of
equalization within the modem than would be required for use on most
national GSTN connections.
Note 2 - The transmit and receive rates in each modem shall be the
same. The possibility of asymmetric working remains for further study.
To order the complete text of this Recommendation, please use the
Order Form for ITU-T Recommendations. An electronic version of this
form is available on ITUDOC (Winword 2.0: UPI=ITU-5265; ASCII: UPI=ITU-2488).