1、 CCITT RECMN*I.25L. L*(REV*L) 92 486259L 0573832 536 = INTERNATIONAL TELECOMMUNICATION UNION CCITT 1.251 .I (rev.1) ME INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE INTEGRATED SERVICES DIGITAL NETWORK (ISDN) GENERAL STRUCTURE AND SERVICE CAPABILITIES DIRECT-DIALLING-IN Recommendation
2、1.251 .I (rev.1) Geneva, 1992 CCITT RECMN*I-251. 1*(REV*KL) 72 W 4862573 0573813 472 INTERNATIONAL TELECOMMUNICATION UNION CCITT 1.251 .I (rev.1) THE INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULTATIVE COMMITTEE INTEGRATED SERVICES DIGITAL NETWORK (ISDN) GENERAL STRUCTURE AND SERVICE CAPABILITIES DI
3、RECT-DIALLING-IN Recommendation 1.251 .I (rev.1) Geneva, 1992 FOREWORD The CCIT (the International Telegraph and Telephone Consultative Committee) is a permanent organ of the International Telecommunication Union 0. CC is responsible for studying technical, operating and tariff questions and issuing
4、 Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The Plenary Assembly of CCm which meets every four years, establishes the topics for study and approves Recommendations prepared by its Study Groups. The approvai of Recommendations by the members of CC be
5、tween Plenary Assemblies is covered by the procedure laid down in CCIIT Resolution No. 2 (Melbourne, 1988). Recommendation 1.251.1 was prepared by Study Group I and was approved under the Resolution No. 2 procedure on the 4th of August 1992. CCIIT NOTE In this Recommendation, the expression “Adminis
6、tration” is used for conciseness to indicate both a telecommunication Administration and a recognized private operating agency. o IW 1992 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 m
7、icrofilm, without permission in writing from the ITU. CCITT RECMN*I.253. 3*K(REV*3) 92 m 4862593 0573835 245 m Recommendation 1.251.1 DIRECT-DIALLING-IN (revised 1992) 1 Defini tion exchange or other private system without attendant intervention. Direct-Dialling-In enables a user to directly call an
8、other user on an integrated services private branch 2 Description 2.1 General description This supplementary service shail be based on the use of the ISDN number. At least the significant part of the ISDN number shal be passed to the private ISDN, in order to progress the call to the destination. Di
9、rect-Dialling-In DI) shail apply to public ISDNs having either a closed or an open numbering plan. 2.2 Specific terminology None. 2.3 Qualcations on the applicability to telecommunication services No restriction to either circuit or packet mode. 3 Procedures 3.1 Provisiodw ithdrawal This service sha
10、il be providedwithdrawn after pre-arrangement with the service provider. The service provider shall allocate a set of ISDN numbers. 3.2 Normal procedures 3.2.1 Activatioddeactivatiodregistration Activation through subscription. 3.2.2 Invocation and operation Cal initiation procedures are the same as
11、 for the basic service. The calling and called users perceive the same completion procedures as for the basic service, without attendant intervention. Upon answer, the calling user is connected to the called user designated by the ISDN number. Note - When the connection from the caller to the integr
12、ated services private branch exchange (ISPBX) is established, the called ISPBX might use the connection for call progress signalling transmission. 3.3 Exceptional procedures 3.3.1 Activatioddeactivatiodregistration Not applicable. Recommendation 1.251.1 1 CCITT RECMN*I.251- L*(REV*L) 92 m 4862593 05
13、73816 181 m 3.3.2 Invocation and operation If the caUed user is busy or does not answer, the procedures for basic calls will apply. If a caU is made by sending incomplete address information, the cai will be released by time supervision within the public exchange. A corresponding time supervision wi
14、thin the ISPBX may also be convenient. 3.4 3.4.1 3.4.2 4 Alternative procedures Activatioddeactivatiodregistration Not identified. Invocation and operation Not identified. Network capabilities for charging This Recommendation does not cover charging principles. Future Recommendations in the D-Seri e
15、xpected to contain that information. It shai be possible to charge the subscriber accurately for the service. 5 6 6.1 6.2 6.3 6.4 2 Interworking requirements No problems identified. Interaction with other supplementary services Call Waiting No impact, i.e. neither supplementary service affects the o
16、peration of the other supplementary service. Call Transfer No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Connected Line Zdentjcation Presentation No impac6 i.e. neither supplementary service affects the operation of the other supplementary se
17、rvice. Connected Line Identifleation Restriction No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Recommendation 1.251.1 s are CCITT RECflN*I.25L. L*i(REV*L) 92 = 48b259L 0573837 O18 W 6.5 Calling Line Identifcation Presentation No impact at the
18、 calling partys user-network interface, except that the network may be supplied with a i) at that interface, in which case a partial or full calling party number may be supplied and may be subject to screening by the network; or ii) (subject to the existence of a special arrangement for not screenin
19、g) at that interface or at another interface to which the same customers equipment (e.g. a private network) is attached, in which case a full (national or international) number may be supplied. calling party number as a result of DDI applying either: At the called partys interface there is no impact
20、, i.e. neither supplementary service affects the operation of the other supplementary service. 6.6 Calling Line Identifcation Restriction No impact, i.e. neither supplementary service affects the operation of the other supplementary service. 6.7 Closed User Group Closed user group membership should
21、not be available on a per DDI number basis, but instead should be on the basis of the entire range of ISDN numbers applicable at the access or group of accesses. 6.8 6.9 6.10 6.10.1 6.10.2 6.10.3 6.10.4 6.11 6.12 Conference Calling No impact, i.e. neither supplementary service affects the operation
22、of the other supplementary service. Direct-Dialling-In Not applicable. Call diversion services Call Forwarding Busy No impact, Le. neither supplementary service affects the operation of the other supplementary service. Call Forwarding No Reply No impact, i.e. neither supplementary service affects th
23、e operation of the other supplementary service. Call Forwarding Unconditional No impact, i.e. neither supplementary service affects the operation of the other supplementary. service. Call Deflection No impact, i.e. neither supplementary service affects the operation of the other supplementary servic
24、e. Line Hunting No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Three-Party Service No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Recommendation 1.251.1 3 CCITT RECMN*Im25Lm L*(REV*L) 92
25、 W 4Bb259L 0573BLB T54 W 6.13 User-to-User Signalling No impact, Le. neither supplementary service affects the operation of the other supplementary service. 6.14 Multiple Subscriber Number No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Note I
26、- In some networks, subscription to the DDI and to the Multiple Subscriber Number (MSN) scpplementary service is mutually exclusive. Note 2 - The DDI digits can be used by the private ISDN in the contact of the private ISDNs multiple subscriber number supplementary service. 6.15 6.16 6.17 6.18 6.19
27、Call Hold No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Advice of Charge No impact, i.e. neither supplementary service affects the operation of the other supplementary service. Multi-Level Precedence and Preemption No impact, i.e. neither sup
28、plementary service affects the operation of the other supplementary service. Priority No impact, Le. neither supplementary service affects the operation of the other supplementary service. Malicious Call Identjcation If DDI is,provided to the served user of Malicious Call Identification (MCID), then
29、 MCID should be provided either globally for the whole access or on a per DDI number basis, according to access arrangements. In both cases, the ISDN number of the called user, including DDI digits, should be registered. 6.20 Outgoing Call Barring No impact, i.e. neither supplementary service affect
30、s the operation of the other supplementary service. 6.21 Reverse Charging No impact, Le. neither supplementary service affects the operation of the other supplementary service, 6.22 Sub-addressing No impact, i.e. neither supplementary service affects the operation of the other supplementary service. 7 Dynamic description The dynamic description is as for basic services. 4 Recommendation 1.251.1
