1、ITU-T RECMN*I-258- 2 95 4862593 Ob00394 085 = INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU 1.258.2 INTEGRATED SERVICES DIGITAL NETWORK (ISDN) SERVICE CAPABILITIES (02/95) IN-CALL MODIFICATION (IM) ITU-T Recommendation 1.258.2 (Previously “CCITT Recommen
2、dation”) ITU-T RECMN*I.258* 2 95 m 4862591 Ob00395 TLL FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommen- dations
3、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 topics. The app
4、roval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). IT-T Recommendation 1.258.2 was prepared by IT-T Study Group 1 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 21st February
5、 1995. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1995 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, el
6、ectronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. CONTENTS 1 2 3 Definition . Description . 2.1 Possible configurations . 2.2 General description . 2.3 Specific terminology . 2.4 Qualifications on the applicability to telecommunication services
7、 . Procedures 3.1 Provision/withdrawal 3.2 Normal procedures 3.3 Exceptional procedures . 3.4 Alternative procedures 4 Network capabilities for charging 5 Interworking considerations . 5.1 Interworking with non-ISDNs 5.2 Interworking with private ISDNs . 1 . Interaction with other supplementary serv
8、ices . 6 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 6.10 6.11 6.12 6.13 6.14 6.15 6.16 6.17 6.18 6.19 6.20 6.21 6.22 6.23 Advice of Charge (AOC) Call Hold (HOLD) Call transfer services . Call Waiting (CW) Closed User Group (CUG) . Completion of calls services . Conference services Diversion services . Dire
9、ct-Dialling-In (DDI) In-Call Modification (IM) . ISDN Freephone (IFS) Line Hunting (LH) Malicious Call Identification (MCID) Multi-Level Precedence and Preemption (MLPP) Multiple Subscriber Number (MSN) Name identification services . Number identification services . Outgoing Call Barring (OCB) . Rev
10、erse Charging (REV) Sub-addressing Support of Private Numbering Plans (SPNP) . Terminai Portability (TP) User-to-User Signalling (WS) 7 Dynamic description Page 1 1 1 1 2 3 4 4 4 4 5 5 5 5 5 6 6 6 6 6 6 6 7 7 7 7 7 7 7 8 8 8 8 8 8 8 8 8 9 9 Recommendation 1.258.2 (02/95) i SUMMARY The In-cai1 Modifi
11、cation (IM) supplementary service enables a user to change within an established (Le. active) call from one type of call characterized by one set of bearer capability, low layer and/or high layer capabilities to another type of call with another set without changing the end-to-end connection from a
12、userhetwork-access point of view. Further in-call modification(s) back to the original or to another call type shall be possible. As a network option, the user can choose, when invoking the supplementary service, that the network automatically modifies the call back to the original call type at the
13、end of the modified part of the connection. 11 Recommendation 1.258.2 (02/95) ITU-T REC“*I-258* 2 95 4862593 Ob00398 720 M Recommendation 1.258.2 IN-CALL MODIFICATION (IM) (Geneva, 1994) 1 Definition The In-call Modification (IM) supplementary service enables a user to change within an established (
14、Le. active) call from one type of call characterized by one set of bearer capability, low layer and/or high layer capabilities to another type of call with another set without changing the end-to-end connection from a userhetwork-access point of view. Further in-call modification(s) back to the orig
15、inal or to another call type shall be possible. As a network option, the user can choose, when invoking the supplementary service, that the network automatically modifies the call back to the original call type at the end of the modified part of the connection. This option is called Double IM. When
16、this option is not supported by the network or is not requested by the user, the invocation of IM is called Single IM. 2 Description 2.1 Possible configurations Several configurations may occur, where IM will be used: 2.1.1 Configuration 1 At both ends of the connection, there exists at least two di
17、fferent single capability terminais. 2.1.2 Configuration 2 (mixed configuration) At one end, there exists multiple capability terminal equipment and at the other end at least two single capability terminais. In this mixed configuration, two cases can be distinguished: - the invocation of IM may occu
18、r at the side with the two or more terminals, so that the existing call can be continued from a second terminal; the invocation of IM may also occur at the side with the multiple capability terminal equipment resulting in a transfer of the existing call to a second terminal at the other end of the c
19、onnection. - 2.1.3 Configuration 3 At both ends, there exists multiple capability terminals. 2.2 General description IM shall be provided on a per call basis. It can be invoked by either the calling or the called party. IM shall be possible also between the following bearer services: - speech; - 64
20、kbit/s unrestricted; - 3.1 kHz audio; - n x 64 kbit/s unrestricted. Other bearer services are for further study. Recommendation 1.258.2 (02/95) 1 ITU-T RECMN*I-258. 2 95 m 4862593 Ob00399 667 m From the service point of view (e.g. bearer service and/or the high and low layer capabilities) there is a
21、 modification of the type of call during the time-frame of the call as depicted in Figure 1. Call Initiation I Invocation of In-call Modification Call me 1 Call Termination I I Call type 2 T0103760941d1 FIGURE 1/1.258.2 Invocation of in-call modification 2.3 Specific terminology 2.3.1 to the ISDN se
22、rvices. terminai; terminal equipment: The physical equipment attached to the ISDN which provides the user access 2.3.2 terminal functions: The functions residing in a terminai which control the network layer functions of the totality of the ISDN and the terminal equipment attached to it. Logically t
23、erminal functions form part of the user. Terminal functions are identified by low and/or high layer compatibility information. 2.3.3 e.g. a telephone or a facsimile group 4 terminal or a videotex terminai, etc. single capability terminal: A terminal which is capable only to handle a single type of c
24、allkommunication, 2.3.4 multiple capability terminal equipment: Terminal equipment or system which is capable of handling more than one type of callkomrnunication at the same interface, e.g. voice and facsimile group 4 and perhaps additionally also facsimile group 3. 2.3.5 service within the scope o
25、f this Recommendation. user: The entity(ies) above the network layer using its services, i.e. the In-call Modification supplementary 2.3.6 served user: The user who invokes the In-call Modification supplementary service. 2.3.7 B-channel or the D-channel with a logical link identifier. user channel:
26、The channel and associated resources as employed for the transfer of user information, e.g. the 2 Recommendation 1.258.2 (02/95) 2.3.8 capability terminal equipment and, at the other end, at least two different single capability terminals (see Figure 2). mixed configuration: A configuration within a
27、n established call where at one end, there exists multiple I I b Single terminals capability ,Il ICDN (publidprivate) 4 h b) Multiple capability terminal I equipment - L TOI 026n)-92/dOI Established connection a) Before invocation of In-call Modification. b) After invocation of in-cai1 Modification.
28、 FIGURE 2n.258.2 Mixed configuration 2.4 Qualifications on the applicability to telecommunication services This functionality is considered meaningful, e.g. especially for facsimile group 4 terminal equipment wishing to control the access of centralized services equipment offering value-added servic
29、es such as, e.g. facsimile store-and-forward service, facsimile database services or message handling services via the ISDN. Specifically, the low featured facsimile group 4, class 1 terminals (send and receive facsimile messages only) have no means of their own to input the necessary control inform
30、ation to the centralized services systems or to output suitable user guidance information back to the user. Thus, other terminals at the same network access must be used, e.g. telephones which serve this purpose already for facsimile group 3 communications or videotex terminals. Both terminal types
31、allow for a transparent control-and-user guidance communication between the user and the centralized service system. All the bearer services mentioned in 2.2 have to be included, as generally available single capability terminals with no special features shall be able to be used, together with in-ca
32、ll modification. In-call modification is also meaningful for the same application as above, when facsimile group 3 terminals are connected within a ISDN. In-call modification should also allow to change between 7 kHz telephony, videotelephony and other bearer services and teleservices. Recommendatio
33、n 1.258.2 (02/95) 3 3 Procedures 3.1 Provisiodwithdrawai In-call modification may be provided after pre-arrangement with the service provider on a subscription basis or be generally available to all network accesses with the ability to invoke it. 3.2 Normal procedures 3.2.1 Activatioddeactivatiodreg
34、istration Not applicable. 3.2.2 Invocation and operation All three configurations and cases mentioned in 2.1 shall be handled as described below. To invoke the In-call Modification supplementary service, the served user shall indicate the necessary information for the new call type, i.e. bearer capa
35、bility, low layer and/or high layer capability to the network. The served user shall also have the capability to indicate a number in order to select a specific terminal out of several terminals of the same type at the local andor at the remote side (e.g. in the context of multiple subscriber number
36、s). The network shall then request the served users terminal function to withdraw from the currently used user channel, bar the selected second terminal against incoming calls and offer the requested call type with the new set of properties as a new call to the selected second terminal. If the same
37、user channel can be re-used, the network shall reserve it for re-establishment of the user-to-network connection. Until this call has been accepted, the second terminaikerminal function shall stay barred against incoming new calls. The network shall also request the remote users terminal function to
38、 withdraw from the currently used user channel, bar the selected second terminal against incoming calls and offer the requested call type with the new set of properties as a new call to the selected second terminal at the remote side. If the same user channel can be re-used, the network shall reserv
39、e it for the re-establishment of the user-to-network connection. Until this call has been accepted, the second terminalhenninal function shall stay barred against incoming new calls. The network shall give the served users first terminal an indication of the successful change to the requested new ca
40、ll type at the remote users side and then release it completely. If the new bearer capability indication results in the need for replacing the original connection, the network shall undertake the actions which are necessary to replace the original intra-network path. This capability is considered an
41、 additional network feature, and its definition is outside the scope of this Recommendation. If the served user has invoked Double IM, the network shall automatically invoke the second part of IM (Le. return to the original call type at the original terminal) upon termination of the modified call. 3
42、.3 Exceptional procedures 3.3.1 Activatioddeactivatiodregistration Not applicable. 3.3.2 Invocation and operation The request for in-call modification shall be rejected in the following cases and the invoking user shall be notified of the cause for rejection: a) b) c) if the second terminal is engag
43、ed in another call which may happen at the local or the remote side; if the desired bearer capability was not subscribed by either party; if the desired (second) terminal does not answer or does not exist; 4 Recommendation 1.258.2 (02/95) d) if the network is not able to reroute the existing call, i
44、f this is necessary to obtain the desired bearer capability or suitable resources are not available; e) if a user requests Double Ih4 and the network does not support this option. The user may then decide whether to request only Single IM or not use the supplementary service. NOTE - Further cases ma
45、y exist. After the notification has been sent to the invoking users terminaihenninal function, the network shall re-establish the connection to the originally served terminal function. 3.4 Alternative procedures 3.4.1 Activationldeactivatiodregistration Not applicable. 3.4.2 Invocation and operation
46、 None identified. 4 Network capabilities for charging This Recommendation does not cover charging principles. Future Recommendations in the D-Series are expected to contain that information. For in-call modification between different bearer services, it shall be possible to charge the subscriber acc
47、urately. In particular, if the calling party is paying for the call, and the called party invokes in-call modification, and this results in a different charge to the calling party, the network shall notify the calling party of the new charge and wait for explicit acceptance from the calling party be
48、fore accepting the in-call modification request. Otherwise the in-call modification invocation request shall be rejected. 5 Interworking considerations 5.1 Interworking with non-ISDNs The In-call Modification supplementary service can be invoked from the ISDN side on calls with interworking into the
49、PSTN for those connections, where both services before and after invocation of IM are supported in the PSTN, e.g. 3.1 kHz telephony and facsimile group 3. In this case, the In-call Modification supplementary service is carried out only up to the ISDNPSTN border. An application is the case when a facsimile group 3 terminal and the telephone, which shall be used to control the centralized service system, are connected to an ISDN and the centralized service system is connected to a PSTN. In this case no indication is given to the remote party in the PSTN. 5.2 Interworking with private ISD
