1、 International Telecommunication Union ITU-T T.30TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU Amendment 1(01/2007) SERIES T: TERMINALS FOR TELEMATIC SERVICES Procedures for document facsimile transmission in the general switched telephone network Amendment 1: Extension of silence period during fa
2、llback from V.34 ITU-T Recommendation T.30 (2005) Amendment 1 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) i ITU-T Recommendation T.30 Procedures for document facsimile transmission in the general switched telephone network Amendment 1 Extension of silence period during fallback from V.34 Summary This Rec
3、ommendation defines the procedures used by Group 3 facsimile terminals as defined in ITU-T Rec. T.4. These procedures enable documents to be transmitted on the general switched telephone network, international leased circuits and the Integrated Services Digital Network (ISDN). Further, these procedu
4、res allow communication to be manual or automatic and for document transmission to be requested alternatively with telephone conversation. Amendment 1 specifies the extension of silence period when the fallback from V.34 fax to normal G3 fax happens in order that the fallback works well. With this r
5、evision, the colour spaces defined in ITU-T Rec. T.30 will be aligned with those in ITU-T Rec. T.44. Additionally, the scope and applicability of T.30 and T.44-based facsimile applications are expanded. The following methods are defined for introducing T.44 YCC colour space to T.30. 1) New negotiati
6、on bit 119 “T.44 colour space“ is added with new Note 83. 2) Note 39 (for bit 74 custom illuminant) and Note 40 (for bit 75 custom gamut range) are modified to reflect the addition of bit 119. Source Amendment 1 to ITU-T Recommendation T.30 (2005) was approved on 13 January 2007 by ITU-T Study Group
7、 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) 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
8、permanent organ of ITU. ITU-T is responsible 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, est
9、ablishes 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 by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary s
10、tandards are prepared on a collaborative basis 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. Compliance with this Recommendation is voluntary. However, the
11、Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalent
12、s are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed
13、 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 date of approval of this Recommendation, ITU had rece
14、ived notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ip
15、r/. ITU 2007 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) 1 ITU-T Recommendation T.30 Procedures for document facsimile transmission in the general switched telephone n
16、etwork Amendment 1 Extension of silence period during fallback from V.34 Modifications introduced by this amendment are shown in revision marks. Unchanged text is replaced by ellipsis (). Some parts of unchanged texts (clause numbers, etc.) may be kept to indicate the correct insertion points. 6.1.3
17、 After receiving a valid CM, the terminal shall follow the procedures described in ITU-T Rec. V.8. However, if the ANSam time-out expires, the answer terminal shall proceed with the binary coded signalling procedures described in clause 5 using the basic 300 bit/s modulation. Bit 6 of the DIS frame
18、shall be set to “1“. When the answer terminal falls back to a normal G3 procedure (e.g., it does not receive CM after sending ANSam, etc.), in order to re-enable echo cancellers, it must wait 450 50 ms before the fallback procedure. The value comes from 250 150 ms described in clause 7.8 “Release ti
19、me“ of ITU-T Rec. G.168. NOTE The terminals which conform to the 2005 and the previous version of this Recommendation may not wait so long. F.5 Examples of sequences 2 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) T0829870-00/d114CNG CI CM CJANSam DIS DIS ANSam JM75 20 msStartCall TerminalAnswer Terminalto
20、 Line Probing Phaseto Line Probing Phase(Note) (Note)NOTE Bit 6 is set to “1“.3 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) Figure F.5-8/T.30 Manual sending 4 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) 5 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) T0829880-00/d115CNG CIANSamCMJMCJCNGCNGANSamDIS75 20 msCall Termin
21、alAnswer TerminalStart(Note)to Line Probing Phaseto Line Probing PhaseNOTE Bit 6 is set to “1“.Figure F.5-9/T.30 Manual receiving 6 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) 7 ITU-T Rec. T.30 (2005)/Amd.1 (01/2007) T0826950-97/d116Call TerminalAnswer TerminalNOTE V.21 modulation modeCNGANSamCMJMCJImage
22、 Data(e.g., Rec. V.17)Training andTCF(TSI) DCS(Note)CFR( Note)(NSF) ( CSI) DIS(Note)75 5msRec. V.8 Normal T.30 ProcedureFigure F.5-10/T.30 Normal T.30 procedure from ITU-T Rec. V.8 Printed in Switzerland Geneva, 2007 SERIES OF ITU-T RECOMMENDATIONS Series A Organization of the work of ITU-T Series D
23、 General tariff principles Series E Overall network operation, telephone service, service 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 Integrate
24、d services digital network Series J Cable networks and transmission of television, sound 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 Telecommunication managem
25、ent, including TMN and network maintenance 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 S
26、eries R Telegraph transmission 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, open system communications and security Series Y Global information infrastructure, Internet protocol aspects and next-generation networks Series Z Languages and general software aspects for telecommunication systems
