1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.90 Amendment 3 (O 6/98) SERIES T: TERMINALS FOR TELEMATIC SERVICES Characteristics and protocols for terminals for telematic services in ISDN Amendment 3: Cause value for a G4 Fax fall-back ITU-T Recommenda
2、tion T.90 - Amendment 3 (Previously CCIll Recommendation) STD.ITU-T RECMN Te90 AND 3-ENGL 3998 4862593 Ob50625 703 ITU-T T-SERIES RECOMMENDATIONS TERMINALS FOR TELEMATIC SERVICES For further details, please refer to ITU-T List of Recommendations, - STDmITU-T RECMN T-90 AND 3-EMGL 1998 M 48b259L 0b50
3、b2b b4T M ITU-T RECOMMENDATION T.90 CHARACTERISTICS AND PROTOCOLS FOR TERMINALS FOR TELEMATIC SERVICES IN ISDN AMENDMENT 3 Cause value for a G4 Fax fall-back Summary Amendment 3 describes cause value for a G4 fall-back to G3-mode. Ten values are added in a table of fall-back codes to be added in I.
4、1 iii)/T.90 and are used for automatic fail-hack G4 to G3 mode. Source Amendment 3 to ITU-T Recommendation T.90, was prepared by ITU-T Study Group 8 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 18th of June 1998. Recommendation T.90/Amd.3 (06/98) 1 FOREWORD ITU (Inte
5、rnational 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 ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Reco
6、mmendations 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 Recommendations on these top
7、ics. 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 IS0 and IEC. NOTE In this Reco
8、mmendation, 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 possibility that the practice or implementation of this Recommendation may involve th
9、e 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 the Recommendation development process. As of the date of approval of this Recomm
10、endation, 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 latest information and are therefore strongly urged to consult the TSB patent database
11、. O ITU 1998 Ail 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 the ITU. ii Recommendation T.90/Amd.3 (06/98) STD-ITU-T RECMN T.90 AMD 3-ENGL 19
12、98 m 4862593 Ob50b28 432 m Introduction and background Most G4 facsimile provides fall-back function from G4-mode to G3-mode. When the call with G4-mode is disconnected with pre-defined cause values, of ISDN service, G4 facsimile tries to make the second call with G3-mode automatically. But, dependi
13、ng on the reason for failure and the specific interworking used by each Operator, it is possible to get different network reactions. Consequently, different cause valu can be received. So, it is needed to show the range of cause values for which G4 Fax 5 should fall back. This new range of cause val
14、ues was proposed and it was decided to add them in Recommendation T.90 at the October 1997 meeting of Study Group 8. . Recommendation T.90/Amd.3 (06/98) 111 STD.ITU-T RECMN T-70 AMD 3-ENGL 1998 m 4862571 0650627 359 m Cause Code 3 Recommendation T.90 Meaning No route to destination CHARACTERISTICS A
15、ND PROTOCOLS FOR TERMINALS FOR TELEMATIC SERVICES IN ISDN 57 58 AMENDMENT 3 Cause value for a G4 Fax fall-back (Geneva, 1998) Bearer capability not authorized Bearer capability not presently available Subclause 1.1 Replace the existing item iii) by: iii) A terminal which supports both G2/G3 and G4 f
16、acsimile function should release the call: - If interworking ISDN to PSTN has been indicated, or causes shown in Table 1.1 for calls within the ISDN, when the call has been rejected, the terminal which supports both G2/G3 and G4 facsimile function may initiate a re-attempt in the G2/G3 mode. It shou
17、ld use the 3.1 kHz audio bearer capability and should provide the HLC information element with high layer characteristics identification “facsimile Group 2/3”. If interworking ISDN, to switched 64 kbit/s non-ISDN network, has been indicated when the call has been rejected, actions according to item
18、ii) may be appropriate. NOTE-For evolution, further study is also required to eliminate the method which may result in unsuccessful calls caused by incompatibility. - 63 65 Table 1.1 - Fall-back codes Service or option not available, unspecified Bearer capability not implemented 70 I 18 I NO user re
19、sponding I Only restricted digital information bearer Capability is available 88 127 Incompatible destination Interworking, unspecified Recomrnenda tion T.90/Amd.3 (06/98) 1 STDmITU-T RECMY T.90 AMD 3-ENGL 1998 W Y862591 Ob50630 070 - ieries A ;enes B ;enes C jeries D Series E Series F Series G Seri
20、es 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 RECOMMENDATIONS SERIES Organization of the work of the ITU-T Means of expression: definitions, symbols, classification General telecommu
21、nication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non-telephone telecommunication services Transmission systems and media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network
22、 Transmission of television, sound programme and other multimedia signais Protection against interference Construction, installation and protection of cables and other elements of outside plant TMN and network maintenance: intemational transmission systems, telephone circuits, telegraphy, facsimile
23、and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring equipment Telephone transmission quality, telephone 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 Programming languages Printed in Switzerland Geneva, 1998
