1、ITU-T RECMN*X.53 93 m 4862.593 05862LL 884 m INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU x.53 (03/93) PUBLIC DATA NETWORKS TRANSMISSION, SIGNALLING AND SWITCHING NUMBERING OF CHANNELS ON INTERNATIONAL MULTIPLEX LINKS AT 64 kbis ITU-T Recommendation X.5
2、3 (Previously “CCITT Recommendation”) ITU-T RECflN*X=53 93 W 48b2591 0586232 710 = FOREWORD The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of the International Telecom- munication Union. The ITU-T is responsible for studying technical, operating and tariff questions an
3、d 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, established the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendation
4、s on these topics. ITU-T Recommendation X.53 was revised by the ITU-T Study Group IX (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 CCITT ceased to exist as of 28 February
5、 1993. In its place, the ITU Telecommunication Standardization Sector (ITU-T) was 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 Similarly, in this reform process, the CCIR and the IFRB have been replaced by the Radiocommunication Sector.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 mad
6、e in the text to references containing the acronyms “CCITT, CCIR or IFRB” or their associated entities such as Plenary Assembly, Secretariat, etc. Future editions of this Recommendation will contain the proper terminology related to the new ITU structure. 2 telecommunication administration and a rec
7、ognized operating agency. In this Recommendation, the expression “Administration” is used for conciseness to indicate both a O ITU 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 mic
8、rofilm, without permission in writing from the ITU. ITU-T RECMNxX.53 93 48b259L 0586213 b57 H Recommendation X.53 NUMBERING OF CHANNELS ON INTERNATIONAL MULTIPLEX LINKS AT 64 kbWs (Geneva, 1980; amended at Malaga-Torremolinos, 1984 and at Helsinki, 1993) The CCITT, considering rhat Recommendations X
9、50, X.51 and R.113 define multiplexing schemes for international links at 64 kbit/s, unanimously declares the following view on the numbering of the tributary channels. Tributary data channels conveyed within a 64 kbit/s multiplex link according to Recommendations X.50, X.51 and R. i i 3, should be
10、 identified, for operational and maintenance purposes, by the following label: i) ii) iii) One decimal digit Dl indicating the multiplexing structure. DI = 1 for the 80 8-bit envelope structure (2m.50). DI = 2 for the 20 8-bit envelope structure (3/X.50). NOTE 1 - This applies to multiplexing struct
11、ures defined in Recommendation X.50 only. One decimal digit D2 indicating the channel rate. D2 = 3,4,5,6,7 and 8 for the rates of 600, 1200.2400,4800,9600 and 48 o00 bit/s respectively. NOTE 2 - Digits 1 and 2 are reserved for user classes of service 1 and 2. Two decimal digits, D3 and Dq, indicatin
12、g the position “n” assigned in the frame with respect to the first envelope of the channel considered; n I 80 for the 80 envelopes frames defined in Recommenda- tion X.50 (clause 2) and Recommendation X.51; n 5 20 for the 20 envelopes frame defined in Recommendation X.50 (see clause 3). Recommendation X.53 (03/93) 1
