1、 INTERNATIONAL TELECOMMUNICATION UNION ITU-T V.92 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1 (07/2001) SERIES V: DATA COMMUNICATION OVER THE TELEPHONE NETWORK Simultaneous transmission of data and other signals Enhancements to Recommendation V.90 Amendment 1 ITU-T Recommendation V.9
2、2 Amendment 1 (Formerly CCITT Recommendation) ITU-T V-SERIES RECOMMENDATIONS DATA COMMUNICATION OVER THE TELEPHONE NETWORK General V.1V.9 Interfaces and voiceband modems V.10V.34 Wideband modems V.35V.39 Error control V.40V.49 Transmission quality and maintenance V.50V.59 Simultaneous transmission o
3、f data and other signals V.60V.99 Interworking with other networks V.100V.199 Interface layer specifications for data communication V.200V.249 Control procedures V.250V.299 Modems on digital circuits V.300V.399 For further details, please refer to the list of ITU-T Recommendations. ITU-T V.92/Amd.1
4、(07/2001) i ITU-T Recommendation V.92 Enhancements to Recommendation V.90 AMENDMENT 1 Summary This document provides an amendment to the 2000 edition of ITU-T V.92. Source Amendment 1 to ITU-T Recommendation V.92 was prepared by ITU-T Study Group 16 (2001-2004) and approved under the WTSA Resolution
5、 1 procedure on 29 July 2001. ii ITU-T V.92/Amd.1 (07/2001) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible
6、 for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing 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 s
7、tudy groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recommendations is covered 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 bas
8、is with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of
9、this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the 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 d
10、ate of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult t
11、he TSB patent database. ITU 2001 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from ITU. ITU-T V.92/Amd.1 (07/2001) 1 ITU-T Recommendation V.92
12、Enhancements to Recommendation V.90 AMENDMENT 1 1) Table 18/V.92 Replace Table 18 with the following: Table 18/V.92 Definition of bits in INFO1aif PCM upstream is selected INFO1abits LSB:MSB Definition 0:3 Fill bits: 1111 4:11 Frame sync: 01110010, where the left-most bit is first in time 12:13 Numb
13、er of filter sections in precoder and prefilter 0 = p1(i) and z2(i) are supported 1 = z1(i), p1(i) and z2(i) are supported 2 = p1(i), p2(i) and z2(i) are supported 3 = z1(i), p1(i), p2(i) and z2(i) are supported 14:15 Integer number indicating the maximum number of coefficients supported by analogue
14、 modem in multiples of 64 starting at 192 Ltot LZ1+ LP1+ LZ2+ LP20 = 192; 1 = 256; 2 = 320; 3 = 384 16:17 Integer number indicating the maximum number of coefficients supported by analogue modem for each filter section in multiples of 64 starting at 128 Lmax max LZ1, LP1, LZ2, LP2 0 = 128; 1 = 192;
15、2 = 256; 3 = 320 18:24 Length of MD to be transmitted by the analogue modem during Phase 3. An integer between 0 and 127 gives the length of this sequence in 276 symbol (34.5 ms) increments 25:31 UINFO: Ucode of the PCM codeword to be used by the digital modem for the 2-point train. The power of thi
16、s point shall not exceed the maximum digital modem transmit power. UINFOshall be greater than 66 32:33 Reserved for the ITU: These bits are set to 0 by the analogue modem and are not interpreted by the digital modem 34:36 Symbol rate of 8000 to be used by the analogue modem: The integer 6 37:39 Symb
17、ol rate of 8000 to be used by the digital modem: The integer 6 40:49 Reserved for the ITU: These bits are set to 1 by the analogue modem and are not interpreted by the digital modem (Note) 50:65 CRC 66:69 Fill bits: 1111 NOTE These bits are set to 1 to avoid generating a tone. 2 ITU-T V.92/Amd.1 (07
18、/2001) 2) Table 19/V.92 Replace Table 19 with the following: Table 19/V.92 Definition of bits in INFO1aif V.34 upstream is selected during short Phase 2 INFO1abits LSB:MSB Definition 0:3 Fill bits: 1111 4:11 Frame sync: 01110010, where the left-most bit is first in time 12:17 Reserved for the ITU: T
19、hese bits are set to 0 by the analogue modem and are not interpreted by the digital modem 18:24 Length of MD to be transmitted by the analogue modem during Phase 3. An integer between 0 and 127 gives the length of this sequence in 35 ms increments 25:31 UINFO: Ucode of the PCM codeword to be used by
20、 the digital modem for the 2 point train. The power of this point shall not exceed the maximum digital modem transmit power. UINFOshall be greater than 66 32 Reserved for the ITU: This bit is set to 0 by the analogue modem and is not interpreted by the digital modem 33 Set to 1 indicates that the hi
21、gh carrier frequency is to be used in transmitting from the analogue modem to the digital modem 34:36 Symbol rate to be used in transmitting from the analogue modem to the digital modem. An integer between 3 and 5 gives the symbol rate, where 3 represents 3000 and 5 represents 3429 37:39 Symbol rate
22、 of 8000 to be used by the digital modem: The integer 6 40:49 The integer 512 indicating that this field is to be ignored 50:65 CRC 66:69 Fill bits: 1111 3) Clause 8.7.6/V.92 Replace 8.7.6 with the following: 8.7.6 TRN2uTRN2uis a 4- or 8-point constellation signal as requested by the digital modem v
23、ia Jpbits 48 and 49. TRN2uconsists of scrambled binary ones. The mapping of the scrambler output to symbols shall be done according to the rules defined in Tables 28 and 29. The scrambler shall be reset at the beginning of TRN2u, except for the second TRN2uin a rate renegotiation with silence. The s
24、ign bit of TRN2uis differentially encoded by modulo 2 addition of the present sign bit with the previously transmitted sign bit. The differential encoder memory shall be initialized with the last transmitted sign bit of the preceding E1usequence during initial train or retrain. It shall be initializ
25、ed with zero for the first TRN2uof a rate renegotiation. It shall be initialized with the last transmitted sign bit of the preceding E2usequence for the second TRN2uof a rate renegotiation. TRN2ushall be an integer multiple of 12 symbols in length. TRN2umay be used to estimate the analogue channel f
26、or upstream. ITU-T V.92/Amd.1 (07/2001) 3 4) Table 31/V.92 Replace Table 31 with the following: Table 31/V.92 Definition of bits in SUVdSUVdbits LSB:MSB Definition 0:16 Frame Sync: 11111111111111111 17 Start bit: 0 18 SUVd: 1 19:31 Reserved for the ITU: These bits are set to 0 by the digital modem a
27、nd are not interpreted by the analogue modem 32 Set to 1 indicates that a silent period is requested. This may be used during rate renegotiation (see 9.8.1.1) 33 Acknowledge bit: 0 = modem has not received CPufrom the analogue modem, 1 = received CPufrom the analogue modem 34 Start bit: 0 35:50 CRC
28、51 Fill bit: 0 52: Fill bits: 0s to extend the SUVdsequence length to the next multiple of 6 symbols 5) Clause 8.6.6/V.92 Replace 8.6.6 with the following: 8.6.6 SCR SCR is a sequence of the PCM codeword whose Ucode is UINFOwith signs generated by applying binary ones to the input of the scrambler a
29、nd then differentially encoding the output of the scrambler. The scrambler shall not be initialized at the beginning of SCR. The differential encoder shall be initialized with the last transmitted sign bit of the preceding Jp sequence at the beginning of SCR. A sign of 0 represents a negative voltag
30、e and a sign of 1 represents a positive voltage. SCR shall be an integer multiple of 6 symbols long. 6) Clause 9.11/V.92 Replace 9.11 with the following: 9.11 Cleardown The cleardown procedure shall be used to terminate a connection. Cleardown is indicated by setting drn to 0 in CPt, CPu, or CPusby
31、the analogue modem or in CPdby the digital modem. This may be signalled at any time that a modem sends a rate sequence. To cleardown from data mode, a modem shall initiate either a rate renegotiation or a fast parameter exchange in order to send a rate sequence with drn = 0. The initiating modem sha
32、ll not request silence in the rate renegotiation and should wait until it receives a CP sequence with the acknowledgement bit set or 100 ms plus 1 round-trip delay after sending its CP sequence before disconnecting from the line. The responding modem should wait 100 ms plus 1/2 round-trip delay afte
33、r sending its CP sequence with the acknowledgement bit set before disconnecting from the line. 4 ITU-T V.92/Amd.1 (07/2001) 7) Table 32/V.92 Replace Table 32 with the following: Table 32/V.92 Definition of bits in MH sequences MH bits LSB:MSB 0:3 Fill bits: 1111 4:11 Frame sync: 01110010, where the
34、left-most bit is first in time Signal indication bits: 0011 MHreq Request remote modem to go on-hold 0101 MHack Indicate agreement to go on hold and timeout 0111 MHnack Deny on-hold, request cleardown or fast reconnect 1001 MHclrd Request cleardown 1011 MHcda Acknowledge cleardown 12:15 1101 MHfrr R
35、equest fast reconnect Information bits: For signals MHreq, MHcda and MHfrr repeat signal indication bits For MHack: 16:19 T1 Timeout period for on-hold For MHclrd: 16:19 16:19 0101 Cleardown due to incoming call 0110 Cleardown due to outgoing call 1010 Cleardown due to other reason For MHnack: 16:19
36、 0101 The current request for Modem-on-hold has been denied. Future requests for Modem-on-hold will also be denied. Therefore, the modem should not initiate another Modem-on-hold request due to an outgoing call request during this session. 0111 The current request for Modem-on-hold has been denied.
37、The modem initiates for another Modem-on-hold request later. 20:35 CRC 36:39 Fill bits: 1111 NOTE 1 Bit combinations not defined in bits 12-15 are reserved for the ITU. MH sequences with undefined bit combinations should be ignored. NOTE 2 Bit combinations not defined in bits 16-19 for MHclrd and MH
38、nack are reserved for the ITU and should not be interpreted by the receiving modem. ITU-T V.92/Amd.1 (07/2001) 5 8) Clause 9.10.1/V.92 Replace 9.10.1 with the following: 9.10.1 Transmission of MH sequences If Tone RT is transmitted before an MH sequence, its duration shall be at least 20 ms if the t
39、one was preceded by another MH sequence, or at least 50 ms otherwise. The transition from data mode to an initiating MH sequence shall be performed by transmitting 70 5 ms of silence followed by an optional Tone RT. MH sequences shall be transmitted repeatedly, with the first 4 fill bits immediately
40、 following the last 4 fill bits of the preceding sequence. Each transmitted sequence shall be completed before transmitting other signals. 9) Figure 20/V.92 Replace Figure 20 with the following: T1610060-0170 5 ms80 msRT MHreqRT MHack ANSamDATA50 ms or 0DATAFigure 20/V.92 Modem-on-hold request ackno
41、wledgedGeneva, 2001 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series B Means of expression: definitions, symbols, classification Series C General telecommunication statistics Series D General tariff principles Series E Overall network operation, telephone service, se
42、rvice operation and human factors Series F Non-telephone telecommunication services Series G Transmission systems and media, digital systems and networks Series H Audiovisual and multimedia systems Series I Integrated services digital network Series J Cable networks and transmission of television, s
43、ound programme and other multimedia signals Series K Protection against interference Series L Construction, installation and protection of cables and other elements of outside plant Series M TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile an
44、d leased circuits Series N Maintenance: international sound programme and television transmission circuits Series O Specifications of measuring equipment Series P Telephone transmission quality, telephone installations, local line networks Series Q Switching and signalling Series R Telegraph transmi
45、ssion Series S Telegraph services terminal equipment Series T Terminals for telematic services Series U Telegraph switching Series V Data communication over the telephone network Series X Data networks and open system communications Series Y Global information infrastructure and Internet protocol aspects Series Z Languages and general software aspects for telecommunication systems
