1、ITU-T RECMN*Q-b04 93 4862591 0584591 TO5 INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU INTERWORKING OF SIGNALLING SYSTEMS Q.604 (03/93) INTERWORKING OF SIGNALLING SYSTEMS - INFORMATION ANALYSIS TABLES ITU-T Recommendation Q.604 (Previously “CCIlT Recomme
2、ndation”) FOREWORD The ITU Telecommunication Standardization Sector (-T) is a permanent organ of the International Telecom- munication Union. The IT-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunicat
3、ions on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, established the topics for study by the IT-T Study Groups which, in their turn, produce Recommendations on these topics. ITU-T Recommendation 4.604 was revised by the ITU-T Study G
4、roup XI (1988-1993) and was approved by the WTSC (Helsinki, March 1-12, 1993). NOTES 1 As a consequence of a reform process within the International Telecommunication Union (ITU), the CCIIT ceased to exist as of 28 February 1993. In its place, the Telecommunication Standardization Sector (ITU-T) was
5、 created as of 1 March 1993. Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector. In order not to delay publication of this Recommendation, no change has been made in the text to references containing the acronyms “CCITT, CCIR or IF” or their
6、associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new IT structure. 2 telecommunication administration and a recognized operating agency. In this Recommendation, the expression “Administration” is
7、 used for conciseness to indicate both a O 1994 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 the IT. ITU-T RECMN*Q.b04 93 m 48b259L 058460
8、3 557 m CONTENTS Page 4.1 Information content of the signals 1 4.2 Consequences 1 . Recommendation Q.604 (OW31 i ITU-T RECMNUQ.604 93 486259L 0584604 493 Recommendation Q.604 INTERWORKING OF SIGNALLING SYSTEMS - INFORMATION ANALYSIS TABLES (Geneva, 1980; modified at Helsinki, 1993) 4 Information ana
9、lysis tables are provided for each signalling system. These tables list the information elements of the forward and backward signals for CCITT signalling systems. Tables A.4 to A.8l) show the forward signals relevant to interworking of Signalling Systems No. 4, No. 5, No. 6, No. 7 (TUP), R1 and R2,
10、split up into their individual information elements. In these tables, comparisons are made between the contents of the signals used by the different systems. Tables A.9 to A.13) show the backward signals relevant to interworking of Signalling Systems No. 4, No. 5. No. 6, No. 7 (I”), R1 and R. split
11、up into their individual information elements. In the rows headed “corresponds to signal No. . . . of Signalling System . . .” the signals are entered together with their corresponding signal, if any, in the different systems. The tables include an indication to the other signalling systems where -
12、- - - equivalent signals have the same information content; equivalent signais are not provided; equivalent signals contain less or substitute information; equivalent signals contain additional or changed information. 4.1 The individual signals are assigned specific information so as to enable messa
13、ges to be transmitted. The meaning of these signals can be seen from the specifications of CC Signalling Systems. With regard to their information content, a basic distinction can be made between signals containing a single information element; and signals containing several information elements. In
14、formation content of the signais - - An information element is understood to be the smallest indivisible component of information (within a signal) considered in this Recommendation. For the interworking of different signalling systems, the information content of the signals to be translated is of g
15、reat importance. In the case where two signalling systems interwork, it is possible to assign all signals used in the CCITT Signalling Systems to one of the following categories: a) b) c) signals coinciding in all information elements; signals coinciding at least in one, but not in all information e
16、lements; signals coinciding in no information element at all. 4.2 Consequences If signals with identical information content are present in the signalling systems, the interworking condition is fulfilled. No modification of information occurs refer to a) of 4.1 above. If the signal meanings do not a
17、gree in all information elements. those signals must be allocated to one another where maximum agreement is to be achieved, so as to minimize the loss or addition of information refer to b) of 4.1 above. See Annex A to Recommandations Q.601-4.608. Recommendation Q.604 (03/93) 1 ITU-T RECMNsQ.604 93
18、m 4862591 0584605 32T m If a signal possesses information elements which are not present in the signals of the other signalling system with which interworking should take place, the information concerned cannot be transmitted and the appropriate performance feature cannot be utilized refer to c) of
19、4.1 above. In a few cases special procedures have to be laid down if the status of the connection does not permit transmission of the intended interworking signal. If conversion is not possible with certain backward signals, it may be necessary to apply a corresponding tone (see Recommendation 4.35). In addition, there are cases in which the information content of several signals of one of the signalling systems has to be converted so as to obtain one signal of the other signalling system and vice versa. 2 Recommendation Q.604 (0-3) -
