1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.140 Addendum 1 (02/2000) SERIES T: TERMINALS FOR TELEMATIC SERVICES Protocol for multimedia conversation Addendum 1 a p p I i ca t io n text ITU-T Recommendation T.140 - Addendum 1 (Formerly CCITT Recommend
2、ation) ITU-T Recommendation T.140 Protocol for multimedia application text conversation ADDENDUM 1 Summary This addendum adds a marker for missing text to T. 140. Source Addendum 1 to ITU-T Recommendation T.140 was prepared by ITU-T Study Group 16 (1997-2000) and approved under the WTSC Resolution N
3、o. 1 procedure on 17 February 2000. ITU-T T.140/Add.l (02/2000) 1 FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is r
4、esponsible 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 Conference (WTSC), which meets every four years, establishes the topics for study by
5、 the ITU-T Study Groups which, in their turn, produce 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 s
6、tandards are prepared on a collaborative basis with IS0 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 The ITU draws attention to the pos
7、sibility 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 Intellectual Property Rights, whether asserted by ITU members or others outside of
8、 the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not 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 late
9、st information 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 any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing fi-
10、om the ITU. 11 ITU-T T.140/Add.l (02/2000) CONTENTS Addendum 1 . Subclause 6.2 . Presentation protocol functions 1) 2) 8.9 Missing text marker Clause 7 . Code elements . Clause 8 . Detailed coding procedures . 3) ITU-T T.14OIAdd.l (02/2000) Page 1 1 1 . 111 ITU-T Recommendation T.140 Protocol for mu
11、ltimedia application text conversation Missing text marker ADDENDUM 1 Marks missing text Introduction The following amendments are essential for implementations of ITU-T Recommendation T. 140, especially when used over unreliable channels. 1) Add the following as the last row in Table 2: Subclause 6
12、.2 - Presentation protocol functions 2) Add the following control sequence at the end of the list: Replacement Character FFFD16 Marker for missing text. Clause 7 - Code elements 3) Add the following new subclause: Clause 8 - Detailed coding procedures 8.9 Missing text marker Purpose: To mark in the
13、text the position of lost character(s). Coding: OxFFFD Graphical representation: A white question mark in a black diamond (see IS0 10646-1). Procedure: The Missing Text Marker “Replacement Character“ should be inserted in the T. 140 data stream by any protocol entity who has discovered a data loss a
14、ffecting some T.140 data. ITU-T T.140/Add.l (02/2000) 1 Series A Series B Series C Series D Series E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V Series X Series Y Series Z ITU-T RECOMMENDATIO
15、NS SERIES Organization of the work of the ITU-T Means of expression: definitions, symbols, classification General telecommunication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmis
16、sion systems and media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network Transmission of television, sound programme and other multimedia signals Protection against interference Construction, installation and protection of cables and other elements
17、of outside plant TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, teleph
18、one installations, local line networks Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communications Global information infrastructure and Internet protocol aspects Languages and general software aspects for telecommunication systems Printed in Switzerland Geneva, 2001
