ITU-T V 90-1998 A Digital Modem and Analogue Modem Pair for Use on the Public Switched Telephone Network (PSTN) at Data Signalling Rates of Up to 56 000 BIT S Downstream and Up to cat.pdf
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1、STDmITU-T RECMN V-70-ENGL 1798 48b2571 0655707 T77 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU v.90 SERIES V: DATA COMMUNICATION OVER THE TELEPHONE NETWORK Simultaneous transmission of data and other signals (O 9/98) A digital modem and analogue modem
2、pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 O00 bitls downstream and up to 33 600 bitls upstream ITU-T Recommendation V.90 (Previously CCITT Recommendation) ITU-T V-SERIES RECOMMENDATIONS DATA COMMUNICATION OVER THE TELEPHONE NETWORK General Inte
3、rfaces and voiceband modems Wideband modems Error control I V.l-V.9 V. 10-V. 34 v.35-v.39 v.40-v.49 I Transmission quality and maintenance v.50-v.59 II Interworking with other networks Interface layer specifications for data communication Control procedures Modems on digital circuits v.lOO-v.199 V .
4、200-V .249 V.250-V.299 v.300-v.399 For further details, please refer to ITU-T List of Recommendations. ITU-T RECOMMENDATION V.90 A DIGITAL MODEM AND ANALOGUE MODEM PAIR FOR USE ON THE PUBLIC SWITCHED TELEPHONE NETWORK (PSTN) AT DATA SIGNALLING RATES OF UP TO 56000 bids DOWNSTREAM AND UP TO 33600 bis
5、 UPSTREAM Summary This Recommendation specifies the operation of a digital modem and analogue modem pair for use on the Public Switched Telephone Network (PSTN) at data signalling rates of up to 56 O00 bit/s in the downstream direction and up to 33 600 bit/s in the upstream direction. The two modems
6、 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 b
7、e national matters and are hence not specified herein. Source ITU-T Recommendation V.90 was prepared by ITU-T Study Group 16 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 25th of September 1998. Recommendation V.90 (09/98) 1 STD-ITU-T RECMN V-SO-ENGL 1798 48b2571 Ob55
8、710 581 D FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommuni- cations. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the IIU. The ITU-T is responsible for studying technical, operating and tarif
9、f questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce
10、Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS
11、0 and IEC. NOTE In this Recommendation the term recognized operating agency (ROA) includes any individual, company, corporation or governmental organization that operates a public correspondence service. The terms Administration, ROA and public correspondence are defined in the Constitution of ihe I
12、TU (Geneva, 1992). INTELLECTUAL PROPERTY RIGHTS The ITLJ draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of claimed
13、 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, the ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommend
14、ation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITU 1999 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mech
15、anical, including photocopying and microfilm, without permission in writing from the ITU. _. 11 Recommendation V.90 (09/98) STD-ITU-T RECMN V-SO-ENGL 1978 i8b2591 Ob55911 414 1 2 3 4 5 6 7 8 CONTENTS Scope References Definitions Abbreviations . Digital modem 5.1 Data signalling rates 5.2 Symbol rate
16、 . 5.3 Scrambler 5.4 Encoder . 5.4.1 Mapping parameters 5.4.2 input bit parsing 5.4.3 Modulus encoder . 5.4.4 Mapper 5.4.5 Spectral shaping 5.4.6 Sign assignment . 5.4.7 Mux . Analogue modem 6.1 Data signalling rates 6.3 Carrier frequencies 6.4 Pre-emphasis . 6.6 Framing . interchange circuits . 6.2
17、 Symbol rates 6.5 Scrambler 6.7 Encoder . 7.1 List of interchange circuits 7.2 Asynchronous character-mode interfacing Start-up signals and sequences . 8.1 8.2 8.3 8.4 Phase 1 Phase 2 8.2.1 A 8.2.2 B 8.2.3 INFO sequences Phase 3 signals for the analogue modem 8.3.2 MD 8.3.3 PP 8.3.4 S . 8.3.5 SCR .
18、8.3.6 TRN . Phase 3 signals for the digital modem . 8.4.1 DIL 8.4.2 Jd . 8.4.3 JA . 8.4.5 TRNld . 8.2.4 Line probing signals 8.3.1 Ja . 8.4.4 sd . Recommendation V.90 (09/98) Page 1 1 2 4 5 5 5 5 5 5 6 6 7 7 10 10 10 11 11 11 11 11 11 11 11 11 11 11 12 12 12 12 12 16 16 17 20 20 20 20 20 20 20 21 21
19、 21 22 . 111 8.5 Phase 4 signals for the analogue modem 8.5.1 B1 8.5.2 CP 8.5.3 E Phase 4 signals for the digital modem . 8.6.1 Bld 8.6.2 Ed 8.6.3 MP . 8.6.4 R 8.6.5 TRN2d . 8.6 9 Operating procedures 9.1 9.2 9.3 9.4 9.5 9.6 9.7 Phase 1 . Network interaction 9.1.1 Use of bits in Recommendation V.8 9
20、.1.2 Call modem . 9.1.3 Answer modem Phase 2 - Probinglranging 9.2.1 Digital modem . 9.2.2 Analogue modem Phase 3 - Equaliser and echo canceller training and digital impairment learning 9.3.1 Digital modem . 9.3.2 Analogue modem 9.4.1 Digital modem . 9.4.2 Analogue modem Phase 4 - Final training . R
21、etrains . 9.5.1 Digital modem . 9.5.2 Analogue modem Rate renegotiation . 9.6.1 Digital modem . 9.6.2 Analogue modem Cleardown . 1 O Testing facilities . 1 1 Gloss asr Appendix I - Overview Page 22 22 22 25 25 26 26 26 27 28 28 28 28 29 29 29 30 31 32 32 34 34 35 36 36 36 36 37 37 38 39 39 40 41 iv
22、Recommendation V.90 (09/98) STDVITU-T RECMN V*SO-ENGL 1978 111 48b259L Ob55713 290 W Recommendation V.90 A DIGITAL MODEM AND ANALOGUE MODEM PAIR FOR USE ON THE PUBLIC SWITCHED TELEPHONE NETWORK (PSTN) AT DATA SIGNALLING RATES OF UP TO 56000 bith DOWNSTREAM AND UP TO 33600 bis UPSTREAM (Geneva, 1998)
23、 1 Scope This Recommendation specifies the operation between two different modems, one a digitai 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 signais and sequences, operating procedures and DTE-DCE interface func
24、tionalities. The network interface of the digitai 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: dupl
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