1、CEPT T/SF*3L-O3*E 89 232bYLY O009200 8 H Page 1 TSF31-03 E - Recommendation T/SF 31-03 E (Vienna 1989 (CAC) TELESERVICES TO BE PROVIDED BY INTEGRATED SERVICES DIGITAL NETWORK (ISDN) Recommendation proposed by Working Group T/WG 7 “Services and facilities“ (SF) Text of the Recornmeridation adopted by
2、 “Telecommimicntioiis“ Commission : Content 1. GENERAL 2. LIST OF STANDARDTSED TELESERVICES 3. EXISTING SERVICES 4. DESCRIPTIONS OF TELESERVICES Annex 1: Telephony Annex 2: Annex 3: Teletex Annex 4: Telefax 4 Annex 5: Mixed Mode Annex 6: Videotex Annex 7: Telex 7 kHz Telephony Service O /, O 3. GENE
3、RAL This Recommendation details the Teleservices to be provided by an ISDN. Teleservices are described by a definition and a set of attribute values which fully describe the service from a users viewpoint. LIST OF STANDARDIZED TELESERVICES FOR THE ISDN The following is an initial list of standardize
4、d Teleservices that should be available in the ISDN: Teleservice Priority 1, Telephony 3.1 kHz E 2. Telephony 7 kHz A 3. Teletex E 4. Telefax E 5. Mixed Mode E 6. Videotex E 7. Message Handling Services A 8. Video Telephony A 9. Video Telephone Conference/Video Conferencing A 10. Surveillance A 11.
5、Picture Mail A 12. Film Retrieval A 13. Audio Retrieval A This will be completed and requirements for each standardized entry will be specified separately. Note. The ISDN should be capable of providing access to a dedicated Telex Network. The Telex users can be accessed through the Teletex service.
6、The interworking of Telex and Teletex has been included as a function of Teletex. EXISTING SERVICES TO BE SUPPORTED ON AN ISDN A list of services that are currently provided by use of existing networks is shown below. The support of these services on the ISDN and in the interim period before a full
7、capability is available requires fiirther study. It is also necessary-to determine the relationship between these services and the definitions of Bearer Services, Teleservices and Supplementary Services. The services so far identified are: - Switched telephony access to public radiophone - Access to
8、 public radiopaging Edition of September 15, 1989 /.- CEPT T/SF*31-03*E 9 W 232b414 0009201 T w T/SF 31-03 E Page 2 4. 4.1. 4.2. 4.3. 4.4. 4.5. 4.6. 4.7. DEFINITIONS OF TELESERVICES TO BE PROVIDED BY ISDNs Full descriptions of the Teleservices to be provided by an ISDN are shown in Annexes 1 to 7. D
9、efinitions are detailed below: Telephony 3.1 kHz The “Telephony Service” provides users with the ability for real time two-way speech conversation via the network. Telephony 7 kHz The 7 kHz Telephony Service provides users with the ability for real time two-way high quality speech conversation via t
10、he network. Teletex Teletex is an international service, enabling subscribers to exchange ofice correspondence in the form of documents containing Teletex coded information on an automatic memory-to-memory basis via the ISDN. Telefax 4 Telefax 4 is an international service, enabling subscribers to e
11、xchange office correspondence in the form of documents containing facsimile coded information automatically via the ISDN. Mixed Mode This service provides combined text and facsimile communication (mixed mode) for end-to-end transfer of documents containing mixed information of text and fixed images
12、. The high layer attributes are based on the CCITT Recommendations for Teletex and Telefax 4. Videotex The Videotex service in the ISDN is an enhancement of the existing Videotex service with retrieval and mailbox functions for text (alpha) and graphic information. Telex This service provides intera
13、ctive text communication. The digital signal at the S/T reference point follows the internationally agreed Recommendations for Telex above the ISDN physical layer. Edition of September 15, 1989- 1. 2. 2.1. 2.2. 3. 3.1. 3.1.1. 3.1.2. T/SF 31-03 E Annex 1, Page 1 Annex 1 TELEPHONY 3.1 KHZ DEFINITION T
14、he “Telephony Service” provides users with the ability for real time two-way speech conversation via the network. DESCRIPTION General Description The “Telephony Service” provides speech transmission at an audio bandwidth of 3.1 kHz. The communica- tion is bidirectional, with both directions continuo
15、usly and simultaneously active during the speech phase. The network may use processing techniques appropriate for speech such as analogue transmission, echo cancellation, and low bit rate encoding. The digital signal at the S/T reference point follows the encoding laws for speech (according to G.71
16、i), A-law or p-law. The network may use digital signal processing techniques. It may also be necessary to use echo cancellation techniques, in particular when interworking with other networks such as the PSTN. User information is provided over a B-channel, signalling is provided over the D-channel.
17、Tones and announce- ments are provided by the network, encoded according to G.711, although terminals can generate tones or other indications based on the messages received. Specific Terminology a) Voice quality The required acoustic performance is described in terms of loudness ratings, frequency r
18、esponse, quantizing distortion, etc.; overall requirements are given in the P-Series of Recommendations. b) Transmission delay The maximum delay is that specified for the general telephone network (cf, Recommendation G. 114). The permissible variation of the actual delay is for further study. c) Ret
19、ention Timer This timer specifies the amount of time that the network retains the call information of the original call upon encountering busy or being released. This timer is a network provider option. The value for this timer is greater than 15 seconds. PROCEDURES Provision/ Withdrawal Provision o
20、f this service will be by arrangement with the Administration/RPOA. This Teleservice is offered with several subscription options which apply separately to each ISDN number or groups of ISDN numbers on the interface. For each subscription option, only one value can be selected. Subscription options
21、for the interface are summarised below: Siibscrption Option Value Maximum number of information channels available at User B Maximum number of total calls present at User B User B can be an ISDN number or group of ISDN numbers on the interface. Note. More than one ISDN number can be associated with
22、the service/interFace only as part of a Supplementary Service such as Multiple Subscriber Number. In the case of one ISDN number, the option given above for the number of calls can only exceed the number of information channels in association with a Supplementary Service (e.g. Call Waiting). As a ne
23、twork provider option, separate values may be specified for incoming and for outgoing calls for either or both of the limits. - m, where m is not greater than the number of information chan- nels on interface - n, where n is not greater than the number of information channels on interface weptember
24、15, 1989 7 q_ T/SF 31-03 E Annex 1, Page 2 3.2. TELEPHONY 3.1 KHZ Normal Procedures a) Originating the Service (Call Set Up) The service is originated by the originating user activating the terminal, performing service selection if applicable for the originating terminal, and terminating customer se
25、lection. During this process the originating user is given the appropriate indications as to the state of the call. i) A service selection is required on a multi-service terminal. ii) Terminating customer selection is selecting the required termination (user/network interface) by an appropriate mean
26、s (for example the use of DDI, multiple subscriber number), iii) Indications during call origination may include an indication that the network is ready to receive the network address information (proceed indication) and an indication that the call is progressing through the network. It shall be pos
27、sible to have audible indications which may be accompanied by other indications. b) Call Acceptance (Answer) Selection of the terminating customer is indicated to each user by appropriate indications (call arrival indication and awaiting answer indication). The acceptance of the call by the terminat
28、ing user (answer) causes the indications to be removed and bidirectional communication paths to be provided. The call is now termed in the “speech phase”. A request to terminate the service may be generated by either user. If one user terminates the service the other user is given an appropriate ind
29、ication as to the state of the call, provided the call has entered the “speech phase”. The following failure situations may occur due to user error: i) User taking too long to input the network address information will be given a failure indication, e.g. during overlap sending (see CCITT Recommendat
30、ion 1.45 i), ii) User inputting a non-valid network address, e.g. an unallocated address, will be given a failure indication. i) User attempting to set up a call to termination where no free B-channels are available will receive a Busy indication unless call waiting or another supplementary service
31、is in operation (Note). Note. In support of some supplementary services (e.g. Call Waiting, Line Hunting) it may optionally be necessary for the subscriber to register some additional parameters (e.g. destination number used to distinguish PSTN telephony calls) with the network to allow the network
32、to know when a channel is busy with telephony. ii) User attempting to set up a call to a termination where the call is not accepted, Le. no response indicating call acceptance is received, will after a defined period be given a call failure indication (see CCIT Recommendation 1.45 1). f) Failure sit
33、uations due to network conditions User attempting to set up a call but meeting problems in the network (e.g. congestion) will be given a suitable indication. c) Call Release d) Failure situations due to user error e) Failure situations due to terminating termination state i) 4. NETWORK CAPABILITIES
34、FOR CHARGING It shall be possible to charge the subscriber accurately for the service. 5. INTERWORKING REQUIREMENTS 5.1. Interworking is required between the ISDN and PSTN. 6. INTERACTION WITH SUPPLEMENTARY SERVICES Not applicable. Each Supplementary Service description identifies the applicability
35、to this Teleservice. I F- Edition of September 15, 198- 7. EPT T/SF*33-03*E 89 m 2326434 0009204 5 m- TIS F 31 -03 E Annex 1, Page 3 TELEPHONY 3.1 KHZ ATTRIBUTES/VALUES a) Low Layer Attributes Information transfer attribiites 1. Information transfer mode: Circuit 2. Information transfer rate: 64 kbi
36、t/s 3. Information transfer capability: Speech 4. Structure: 8 kHz integrity 5. 6. Communication configuration: Point-to-point 7. Symmetry: Bidirectional Symmetric Access attributes 8. Access channel (and rate): B(64) for user information, D for signalling (Note) 9.1 Signalling access protocol layer
37、 1 : 1.430/1.431 9.2 Information access protocol layer 1 : 1.430/1.431; G.711 9.3 Signalling access protocol layer 2: 1.440/1.441 9.4 Information access protocol layer 2: - 9.5 Signalling access protocol layer 3: 1.450/1.451 9.6 Information access protocol layer 3: - Note. For reserved/permanent ser
38、vice the operational, administrative and maintenance messages related to these services may be conveyed over the D-channel. b) High Layer Attributes 10. Type of user information: Speech 11. Layer 4 protocol functions: - 12. Layer 5 protocol functions: - 13. Layer 6 protocol functions: G.711 14. Laye
39、r 7 protocol functions: - c) Genernl Attribiites 15. Supplementary low layer and high layer attributes (supplementary services) : 16. User-oriented quality of service: FS 17. Interworking possibilities: to and from PSTN 18. Operational and commercial aspects: FS Note. - =Not Applicable. Establishmen
40、t of communication: On Demand FS = For Further Study. 8. DYNAMIC DESCRIPTION The circuit mode dynamic description appears in Recommendation 1.220. Fweptember IS, 1989 7 .*I_- CEPT T/SF*33-03*E 89 = 2326434 0009205 7 I_ TIS F 31 -03 E Annex 2, Page 1 Annex 2 TELEPHONY 7 KHZ 1. DEFINITION The 7 kHz Te
41、lephony Telecommunication Service provides users with the ability for real time two-way high quality speech conversation via the network. 2. DESCRIPTION The 7 kHz Telephony Service provides, via the network, the abiiity to transfer high quality speech allowing users to communicate by interchanging s
42、ounds with a high quality. The communication is bidirectional, with both directions continuously and simultaneously active during the speech phase. This service provides high quality speech communication with a frequency range from 50 to 7000 Hz. The digital signal at the S/T reference point follows
43、 the internationally agreed encoding laws for high quality speech (G.722). User information is provided over a B-channel, signalling is provided over the D-channel. Tones and announcements are provided by the network; however, the way in which the network encodes these tones and announcements is for
44、 further study. Terminals can, however, generate tones or other indications based on the messages received. 3. OPERATIONAL REQUUIREMENTS a) Originating the Service (Call Set Up) The service is originated by the originating user activating the terminal, performing service selection, if applicable for
45、 the originating terminal, and terminating customer selection. During the call set up stage the originating user is given the appropriate indications as to the state of the call. i) Service selection is required on multi-service terminals and may consist of directly selecting the service “7 kHz Tele
46、phony”. ii) Terminating customer selection is selecting the required termination (userlnetwork interface) by means of the appropriate network number. In association with 7 kHz Telephony a specific terminal on that interface may be selected by the use of e.g. DDI or sub-addressing. iii) Indications d
47、uring call origination may include an indication that the network is ready to receive the network address information (proceed indication) and an indication that the call is progressing through the network. It shail be audible indications but may also be accompanied by other indica- tions. b) Call A
48、cceptance (Answer) Selection of the terminating customer is indicated to each user by appropriate indications (call arrival indication and awaiting answer indication). The acceptance of the call by the terminating user (answer) causes the indications to be removed and bidirectional communication pat
49、hs to be provided. The call is now termed in the “speech phase”. c) Terminating the Service (Call Release) A request to terminate the service may be generated by either user. If one user terminates the service the other user is given an appropriate indication as to the state of the call, provided the call has entered the “speech phase”. The following failure situations may occur due to user error: i) User taking too long to input the network number information will be given a failure indication where overlap sending applies (see CCITT Recommendation 1.45 1). ii) User inputting
