T-REC-T.38-200704-I!!PDF-E.pdf

I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T T.38 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2007) SERIES T: TERMINALS FOR TELEMATIC SERVICES Facsimile Group 3 protocols Procedures for real-time Group 3 facsimile communication over IP networks ITU-T Recommendation T.38 ITU-T T-SERIES RECOMMENDATIONS TERMINALS FOR TELEMATIC SERVICES Facsimile Framework T.0T.19 Still-image compression Test charts T.20T.29 Facsimile Group 3 protocols T.30T.39 Colour representation T.40T.49 Character coding T.50T.59 Facsimile Group 4 protocols T.60T.69 Telematic services Framework T.70T.79 Still-image compression JPEG-1, Bi-level and JBIG T.80T.89 Telematic services ISDN Terminals and protocols T.90T.99 Videotext Framework T.100T.109 Data protocols for multimedia conferencing T.120T.149 Telewriting T.150T.159 Multimedia and hypermedia framework T.170T.189 Cooperative document handling T.190T.199 Telematic services Interworking T.300T.399 Open document architecture T.400T.429 Document transfer and manipulation T.430T.449 Document application profile T.500T.509 Communication application profile T.510T.559 Telematic services Equipment characteristics T.560T.649 Still-image compression JPEG 2000 T.800T.849 Still-image compression JPEG-1 extensions T.850T.899 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. T.38 (04/2007) i ITU-T Recommendation T.38 Procedures for real-time Group 3 facsimile communication over IP networks Summary This Recommendation defines the procedures to be applied to allow Group 3 facsimile transmission between terminals where in addition to the PSTN or ISDN a portion of the transmission path used between terminals includes an IP network, e.g., the Internet. This revision of ITU-T Recommendation T.38 clarifies H.323, H.248.1, SIP and SDP call establishment and improves the compatibility between T.38 gateways and Group 3 facsimile. Source ITU-T Recommendation T.38 was approved on 6 April 2007 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. T.38 (04/2007) 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 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, 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 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 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 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 equivalents 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 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 received 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/ipr/. ITU 2008 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.38 (04/2007) iii CONTENTS Page 1 Scope . 1 2 Normative references. 1 3 Definitions. 2 4 Abbreviations. 2 5 Introduction . 3 6 Communication between gateways. 5 6.1 Internet protocol TCP or UDP. 5 6.2 Gateway facsimile data transfer functions . 5 7 IFT protocol definition and procedures. 6 7.1 General . 6 7.2 IFP packet format. 8 7.3 TYPE definitions. 9 7.4 The IFP DATA element . 11 7.5 Limitation of V.21 frame packet size. 13 8 IFP mes