1、- CEPT T/SF*b2*E 88 2326434 0009525 3 TISF 62 E Page 1 Recommendation T/SF 62 (Edinburgh 1988) SUPPLEMENTARY SERVICE DIGITAL CONNECTIVITY FOR TELESERVICES Recommendation proposed by Working Group T/WG 7 “Services and facilities” (SF) Text of the Recommendation adopted by “Telecomnuiiications” Commis
2、sion: “The European Conference of Posts and Telecommunications Administrations, considering - that both conventional analog networks and digital IDN/ISDN networks will exist simultaneously for a long - that a great demand is envisaged for Teleservices using 64 kbit/s connections in the early phase o
3、f IDN and ISDN - that public nehvorks will provide a competitive and cost-effective means of providing Teleservices operating on period of time, introduction, 64 kbit/s, recommends - that a supplementary service Digital Connectivity for Teleservices should be standardized on the bases of user and op
4、erational requirements as presented in this document.” A SERVICE PROSE DEFINITION AND DESCRIPTION 1. 2. 3. 3.1. 3.1.1. 3.1.2. 3.1.3. 3.1.4. DEFINITION The digital connectivity is a user facility that enables user to establish a fully digital path at 64 kbit/s user-to-user(s). DESCRIPTION Supplementa
5、ry service Digital Connectivity is an optional facility assigned to the user and provided on a call request basis (version a) or by specic subscriber category (version b). A natural condition is that both A- and B-subscribers have a digital subscriber line. OPERATIONAL REQUIREMENTS General requireme
6、nts Provision The Administration provides the service on a subscription base. This applies for the both two cases of the service, i.e. the service applies for ail calls or the service is activated on a call-based request. Withdrawal The Administration will withdraw the service at the request of the
7、subscriber or for administrative reasons. Invocation When the service is provided for all calls it will automatically be invoked by the network at the call set up. For on a call based request it will be invoked at the activation of the service by the user using a service code as described in paragra
8、ph 4. Normal operation witti successfit1 outcoine At a call set up when the network identifies a digital connectivity request, an attempt on the possibility to route the call on a digital path is made by the network: If the attempt is successful, the call is routed on 64 kbit/s routes. E$tion of Oct
9、ober 15, 1988 TJSF 62 E Page 2 3.1.5. 3.1.6. 3.2. 3.2.1. 3.2.2. 3.2.3. 3.2.4. 3.3. 3.4. 3.5. Exceptional operation or unsuccessjhl outcome At a call setup when the network identifies a digital connectivity request, an attempt on the possibility to route the call on a digital path is made by the netw
10、ork: If the attempt is unsuccessful, the call is rejected and the subscriber will receive an appropriate indication: - an appropriate announcement and/or a visual indication, e.g. “digital path not provided” in case where - a congestion tone in case where a digital path exists but it is not possible
11、 to complete the call due to a routing that allows a complete digital path doesnt exist, or congestion or failure. Quality of service Quality of service requirements are the same as set for the Teleservice(s) provided to the concerned subscriber lines. Important quality of service character at the e
12、arly provision of the service is the number of unsuccessful calls due to lack of digital path, and certain measures should be set to be a threshold of the marketing of the service. This is for further study. Controlling subscriber requirements Activationldeactivation In version a), activation occurs
13、 together with invocation; the service is automatically deactivated after each call. In version b), the supplementary service is activated on provision by the Administration, using the operation and maintenance interface and the service remains continuously activated until withdrawal. Invocation In
14、version a), the service is invoked by means of control procedure which includes a call request. In version b), the service is automatically invoked on each call set up. Test ng The subscriber may test the service by using it. Interrogation Interrogation of the registered information may be provided.
15、 Service operation requirements Advanced signalling systems such as CCITT SS No. 7 makes it possible to select a 64 kbit/s path and to inform. the concerned subscribers accordingly. However, some digital 64 kbit/s connections may use conventional signalling systems with limitations in this respect.
16、Therefore, a handshaking operation is necessary between the originating subscribers and destinating subscribers connection in order to verify an end-to-end 64 kbit/s connectivity. Interaction with other supplementary services The service relates to call set-up phase. Compatibility with supplementary
17、 services such as abbreviated dialling where a subscriber control procedure for use of the service is necessary at the call set-up phase should be resolved for the on a call-based request case of the service. The following is recommended for a simultaneous use of abbreviated dialling and digital con
18、nectivity call set-up : LH DT* 32* AN . for prefix method LH DT* 32* AN # , for suffix method when procedures harmonized for the 12-button terminal are used. Interworking considerations When the service is invoked and a call has been Set-up, call waiting and operator intrusion or any other form of s
19、upervisory tones and announcements applied after answer are not allowed either to the A-sub- scriber or to the B-subscriber if these interrupt the 64 kbit/s channel. This applies to teleservices other than telephony. Problems of interworking between networks require further study. Edition of October
20、 15, 1988 CEPT T/SF*b2*E 88 2326414 000952b 5 T/CF 62 E Page 3 3.6. 3.7. 4. 4.1. 4.2. 4.3. 4.4. 4.5. Administration requirements The service is provided by the Administration on a subscription base. At provision the specific subscriber category and the type of service required is registered into the
21、 network by the Administration. The Administration erasures the service at the withdrawal of the service. Charging requirements A charge for the registration of the service together with a rental charge for, and provision period of, the service should apply. It shall be possible to charge as for nor
22、mal call, or at a higher rate. An additional charge for the use of the service at each call may apply. Interrogation may be charged if provided. CONTROL POSSIBILITIES General Service code 32 is allocated for the on a call-based request case of the service. Registration/Erasure Not applicable. Activa
23、tion/Deactivation There are no separate control procedures for activation/deactivation (see paragraph 3.2.1 .). ho ca tion For version a) the recommended control procedure for the standard 12-button terminal. LH DT For version b) there is no specific invocation procedure (see paragraph 3.2.2.). The
24、service is automatically invoked on each normal call set-up procedure. 32 (*) TN (#) Interrogation Not applicable. . Edition of October 15, 1988 7 I CEPT T/SF*b2*E 88 I 2326414 0009528 9 I T/SF 62 E Page 4 A DYNAMIC DESCRIPTION User Calling user A A calls B Digital Connectivity request: - automatic
25、from the network - with service code A calls B r IND: call is reiected - no digital path or - congestion IND: call is rejected Y - B is busy ietwork interface Service request is forwarded and compatibility check is done by the network Call is set up or Service request is forwarded or Service request
26、 is forwarded and compatibility check is done Called user B Ring B _, B answers e- B is busy Edition of October 15, 1988 CEPT T/SF*b2*E 88 2326434 0009529 B? TABLE OF ATTRIBUTES AND THEIR POSSIBLE VALUES Attribute name 1, Means of subscription/provision (MS) 2. Supplementary service specific paramet
27、ers (SSP) 3. Service activation/deactivation (SA/D) 4. Means of specified period activation/deactivation (MSA) 5. Means of parameter registration, interrogation and modification (PRM) 6. Means of service invocation (MSI) 7. Applicability to telecommunication services (AT) 8. Charging 9. Compatibilit
28、y Legends : ASD AVD cc I L MSS N R S SP TEL TI TTX U UNR VBD TTF 64 kbitls unrestricted, alternate speech, data 64 kbit/s alternate speech, 3.1 kHz Call-by-call ISDN address User controlled, local Maximum service size Network controlled User controlled, remote Specified periods 64 kbit/s speech Telephony Time related information Teletex User identification 64 kbitls unrestricted 64 kbitls voiceband data, 3.1 kHz audio Telefax - T/SF 62 E Page 5 Possible values N I cc, s N N, L N, L UNR, SP, VBD, ASD, AVD, TEL, TTX, TTF Videophone For further study For further study
