1、INTERNATIONAL TELECOMMUNICATION UNION ITWT TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU v.91 Corrigendum 1 (071200 1 ) SERIES V: DATA COMMUNICATION OVER THE TELEPHONE NElWORK Simultaneous transmission of data and other signals A digital modem operating at data signalling rates of up to 64 O00 bit
2、/s for use on a 4-wire circuit switched connection and on leased point-to-point 4-wire digital circuits Corrigendum 1 ITU-T Recommendation V.91 - Corrigendum 1 (Formerly CCITT Recommendation) ITU-T V-SERIES RECOMMENDATIONS DATA COMMUNICATION OVER THE TELEPHONE NETWORK General Interfaces and voiceban
3、d modems Wideband modems Error control Trammission quality and maintenance Ki smission of networks Interface layer specifications for data communication Control procedures Modems on digital circuits v. 1-v.9 V.10-V.34 v.35-v.39 v.40-v.49 v.50-v.59 v.100-v.199 V.200-V.249 V.250-V.299 V.300-V.399 Forj
4、rther details, please refer to the list of ITU-T Recommendations. ITU-T Recommendation V.91 A digital modem operating at data signalling rates of up to 64 O00 bids for use on a 4-wire circuit switched connection and on leased point-to-point 4-wire digital circuits CORRIGENDUM 1 Summary This corrigen
5、dum provides corrections to 8.2.1.6 and to 8.2. Source Corrigendum 1 to ITU-T Recommendation V.91 was prepared by ITU-T Study Group 16 (2001 -2004) and approved under the WTSA Resolution 1 procedure on 29 July 2001. ITU-T V.9l/Cor.l(07/2001) i FOREWORD The International Telecommunication Union (IT)
6、is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. IT-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizi
7、ng telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered
8、by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and lEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate
9、both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the
10、 evidence, validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which
11、may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest idormation and are therefore strongly urged to consult the TSB patent database. o ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in an
12、y form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. 11 IT-T V.9UCor.l (07/2001) ITU-T Recommendation V.91 A digital modem operating at data signalling rates of up to 64 O00 bit/s for use on a 4-wire circuit switched connecti
13、on and on leased point-to-point 4-wire digital circuits CORRIGENDUM 1 1) Clause 8.2 Modifi the first paragraph of 8.2 as follows: 8.2 V.91 start-up The modem may initiate a retrain at any time during start-up (e.g. error events) or data mode according to 8.4.1. Examples of V.91 start-up procedures a
14、re shown in Figures 1 , 2, and 3. 2) Clause 8.2.1.6 Modi3 8.2. I. 6 as follows: 8.2.1.6 The modem shall then send PHIL until it has the information necessary to provide the DIL requested by the peer modem. If it already has the information necessary to provide the DIL requested by the peer modem, it shall proceed to 8.2,1.7 without transmitting PHIL. If the modem is receiving J and it fails the CRC check, the modem shall initiate a retrain according to 8.4.1. ITU-T V.Bl/Cor.l (07/2001) 1 -
