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INTERNATIONAL TELECOMMUNICATION UNION

 

TELECOMMUNICATION 

STANDARDIZATION SECTOR

STUDY PERIOD 1997 - 2000

COM 16-R 24-E

March 1998

Original: English

Questions 4
and 23/16

STUDY GROUP 16 REPORT
R 24

SOURCE*: STUDY GROUP
16 (GENEVA MEETING, 26 JANUARY - 6 FEBRUARY 1998)

TITLE: REPORT OF WORKING
PARTY 1/16 (LOW RATE SYSTEMS) 

 PART II B - DETERMINED RECOMMENDATION

________

TABLE
OF CONTENTS

Page

1. Draft revised ITU-T
Recommendation V.8<span class="TOC-00201--Char" style=" font-style: italic;
">bis   2

2. Draft new ITU-T Recommendation V90 (ex-V.pcm)  
3

Attention:
This is not an ITU publication made available to the public, but an internal
ITU Document intended only for use by the Member States of the
ITU and by its Sector Members and their respective staff and collaborators
in their ITU related work. It shall not be made available to, and used
by, any other persons or entities without the prior written consent
of the ITU.

 

1. Draft revised ITU-T Recommendation V.8<span
class="Heading-00201--Char" style=" font-style: italic;">bis

The text of draft revised ITU-T Recommendation V.8<span
class="Normal--Char" style=" font-style: italic;">bis (Procedures
for the identification and selection of common modes of operation between
data circuit-terminating equipments (DCEs) and between data terminal
equipments (DTEs) over the general switched telephone network and on
leased point-to-point telephone-type circuits.) will be provided by
the Rapporteur as a white contribution, to reach TSB prior to 11 May
1998, based on the text reproduced in Annex B to  

COM 16-R 23.

2. Draft new ITU-T Recommendation V.90 (ex
V.pcm)

The final text of draft new ITU-T Recommendation V.90
will be provided by the Rapporteur as a white contribution, to reach
TSB prior to 11 May 1998, based on the following text.

 

DRAFT NEW ITU-T RECOMMENDATION V.90 (EX-V.PCM)

A DIGITAL MODEM AND
ANALOGUE MODEM PAIR FOR USE ON THE PUBLIC SWITCHED TELEPHONE NETWORK
(PSTN) AT DATA SIGNALLING RATES OF UP TO 56000 BIT/S DOWNSTREAM AND
UP TO 33600 BIT/S UPSTREAM

1. Scope

This Recommendation specifies the operation between
two different modems, one a digital modem and the other an analogue modem,
both as defined in clause 3. The two modems are specified herein in
terms of coding, start-up signals and sequences, operating procedures
and DTE-DCE interface functionalities. The network interface of the
digital modem and the signalling rate that is used to connect the digital
modem locally to a digital switched network are considered to be national
matters and are hence not specified herein. The principal characteristics
of these modems are as follows:

duplex mode of operation on a PSTN and a switched
digital network;
ch</span><span class="List-0020Number-00202--Char" style=" font-family: 'Times New Roman', 'Arial';
font-size: 12pt;">annel separation by echo cancellation techniques;
PCM modulation in the downstream direction at a symbol
rate of 8000;
synchronous channel data signalling rates in the
downstream direction from 28000 bit/s to 56000 bit/s in increments of
8000/6 bit/s;
V.34 modulation in the upstream direction;
synchronous channel data signalling rates in the
upstream direction from 4800 bit/s to 28800 bit/s in increments of 2400
bit/s, with optional support for 31200 bit/s and 33600 bit/s;
adaptive techniques that enable th</span><span class="List-0020Number-00202--Char" style=" font-family: 'Times New Roman', 'Arial';
font-size: 12pt;">e modems to achieve close to the maximum data signalling
rates the channel can support on each connection;
fallback to full duplex V.34 operation if a connection
will not support V.pcm operation;
exchange of rate sequences during start-up to establish
the data signalling rate;
automoding to V.-Series modems supported by V.32 bis automode procedures and group 3 facsimile machines;
Use of V.8, and optionally V.8 bis, procedures during modem start-up or selection.

 

2. References

The following Recommendations contain provisions which,
through reference in this text, constitute provisions of this Recommendation.
At the time of publication, the editions indicated were valid. All Recommendations
are subject to revision; all users of this Recommendation are therefore
encouraged to investigate the possibility of applying the most recent
editions of the Recommendations listed below. A list of currently valid
ITU-T Recommendations is regularly published.

- ITU-T
(CCITT) Recommendation G.711:  1988, Pulse code modulation (PCM)
of voice frequencies.

- ITU-T
Recommendation T.30:  1996, Procedures for document facsimile transmission
in the general switched telephone network.

- ITU-T
Recommendation V.8:  1998, Procedures for starting and ending sessions
of data transmission over the public switched telephone network.

- ITU-T
Recommendation V.8 bis:  1996, Procedures for the identification and selection
of common modes of operation between data circuit-terminating equipments
(DCEs) and between data terminal equipments (DTEs) over the general
switched telephone network and on leased point-to-point telephone-type
circuits.

- ITU-T
Recommendation V.14:  1993, Transmission of start-stop characters
over synchronous bearer channels.

- ITU-T
(CCITT) Recommendation V.24:  1988, List of definitions for interchange
circuits between data terminal equipment (DTE) and data circuit-terminating
equipment (DCE).

- ITU-T
Recommendation V.25:  1996, Automatic answering equipment and general
procedures for automatic calling equipment on the general switched telephone
network including pro