1、 Page E 1 Recommendation T/SF 45 (Odense 1986) SERVICES AND FACILITIES FOR SUBSCRIBER COMPLEX INSTALLATIONS (INCLUDING ISPBX AND LAN INSTALLATIONS) CONNECTED TO AN INTEGRATED SERVICES DIGITAL NETWORK (ISDN) Recommendation proposed by Working Group T/WG 7 “Services and facilities” (SF) Text of the Re
2、commenda tio adop ted by Commission “Telecomil-tunicn t ions” : “The European Conference of Posts and Telecommunications Administrations, considerifig 1. that Integrated Services Digital Networks (ISDN) will make available New Services and Facilities for Customers Private Branch Exchanges (PBX) and
3、Local Area Networks (LAN) and allow the evolution of dedicated service PBXs (e.g. for voice only) to Integrated Services PBXs (ISPBXs), 2. that there is merit in harmonizing the form in which these services are given to simplify their operating procedures, 3. that the services provided by one ISPBX
4、or LAN may require to interface to those services provided by another 4. that harmonized services should result in lower overall costs and faster growth, 5. that there is a need to develop within a common framework coherent arrangements for ISPBX or LAN access 6. that there are National Numbering Pl
5、ans in terms of length and structure, 7. that there is a need to utilise one existing world numbering plan if possible, 8. that the increase in the number length must be as small as possible, ISPBX or LAN using the ISDN, and also to other users of the ISDN, to different services provided, recommieid
6、s to CEPT members 1. 1.1. 2. 2.1. 2.2. GENERAL Application of Recommendation That in general the requirements of this recommendation should apply equally to LANs and ISPBXs when connected to an ISDN. The application to other Complex Installations requires further study. DEFlMTION OF ISPBX AND LAN IS
7、PBX An ISPBX is a PBX which may support any or all services that can be supported by ISDN basic access. Each extension of an ISPBX may support one or a range of service terminals, e.g. telephony, data and telex, etc. LAN A data communication-system, which allows a number of independent data devices
8、to communicate with each other. A local area network is distinguished from other types of data networks in that the communica- tion is confined to a moderate-sized geographic area, such as one ofice building, one warehouse, or one campus, etc. and a moderate data rate. This is in contrast to long-di
9、stance networks which interconnect ofices in different parts of the country, networks which interconnect equipment in one room, or networks or devices inside one piece of equipment. Edition of November 15, 1986 -_ CEPT T/SF*45*E Ab 232b41i4 0009395 5 TfSF 45 E Page 2 3. 4. 4.1. 4.2. 5. 6. 6.1. 6.2.
10、6.3. 6.4. 7. 7.1. 7.1.1. 7.1.2. 7.2. 7.2.1. 7.2.2. 7.2.3. TELECOMMUNICATIONS SERVICES AVAILABLE TO ISPBXs That an ISPBX/LAN may use any or all of the Standardized Bearer Services and Teleservices that can be supported by a basic subscribers access in the ISDN and any additional services provided by
11、the ISPBS/ LAN itself or any non-standardized Bearer Services and Teleservices to which the ISPBX/LAN is connec- ted. The Standard Teleservices that may be available to ISPBXs/LANs are summarised in Annex A. NON-STANDARDIZED Bearer Services and Teleservices That the ISDN should be able to offer non-
12、standardized Bearer Services and Teleservices between ISPBXs/ LANs. The details of these services require further study. That means should be provided by the ISDN to permit end to end signalling between ISPBXs/LANs (linked by non-standardized Bearer Services and Teleservices). The detailed requireme
13、nts are for further study. SUPPLEMENTARY SERVICES Supplementary services are dealt with in a separate recommendation. NETWORK INTERFACE REQUIREMENTS That Administrations will require that there should be a clearly defined physical and electrical interface at the subscribers premises delineating subs
14、criber and network responsibilities and to enable isolation of fault conditions either to within the ISPBX/LAN or ISDN. That there should be a means of testing the ISDN access between the ISDN local exchange and the interface mentioned in paragraph 6.1. above. That whilst it is recognised that diffe
15、rent sizes of ISPBXs/LANs will require different access methods, e.g. small ISPBXs/LANs a number of basic accesses whilst large ISPBXs/LANs one or more high speed links (e.g. 2 Mbit/s) employing n x 64 kbit/s channels and one signalling channel, this should not affect the Services and Supplementary
16、Services that can be used. That it is likely that subscribers will require some ISPBXs/LANs to interface with both the existing networks and the ISDN. This item requires further study. CALL HANDLING FOR ISPBXs/LANs Channel Selection Requirements That the method or methods chosen for Channel Selectio
17、n should provide mutually acceptable flexibility for both the customer and the Network and cause the minimum delay to the Callconnection. That there should be the minimum possibility of both ends simultaneously selecting the same circuit. Handling of Incoming Caus That, in the case of DDI, the valid
18、ity of the extensions address should also be checked unless the tariffs applied raise a charge for every national number available to the subscriber. This may only be required by some Administrations depending on the tariff structure used by those Administrations. That, if the compatibility checks a
19、re successful and a suitable channel is available, the call should be offered to the ISPBX/LAN, together with an indication of the service required. At this point the ISDN shall have an option to commence call charging (see paragraph 8). That if the ISPBX/LAN is free to accept the call (e.g. Not Con
20、gested) the ISPBX/LAN should: (a) For General Directory Number Calls (Le. Non-DDI Calls): Acknowledge the arrival of the call with a Call Accepted Message indicating that the ISPBX/LAN is free and : i) for voice calls-offer the call to the operator, ii) for non-voice calls the ISPBX/LAN should act i
21、n one of the following ways: - respond itself as a terminal and answer the call using the protocol appropriate to the Service indicated in the incoming call message. Further handling of the contents of the call is not the responsibility of the Public Network and is therefore not proper to this recom
22、mendation, Edition of November 15, 1986 CEPT T/SF*45*E 86 2326434 0009396 7 7.2.4. 7.2.5. 7.2.6. 7.3. 8. 8.1. 8.2. O 9. 1 o. 11. TIS 45 E Page 3 - offer the call to a suitable predetermined terminal. Note: The response would have to be in accordance with the operational requirements of the ISDN and
23、the particular service. (b) For DDI Calls: The ISPBX/LAN should ascertain the state of the required extension terminal. If the extension is free and a suitable channel is available the ISPBX/LAN should offer the call to the terminal and return a call Accepted Message to the Network. (c) For Sub-Addr
24、essing Calls : This needs further study. That if a channel is not available, the network should release the call and a congestion indication or a subscriber engaged indication should be given to the calling terminal. That on receipt of a Call Not Accepted Message from the ISPBX/LAN stating that the
25、ISPBX/LAN is congested or that the required extension is Busy, the ISDN should release the call and return Subscriber Engaged indication to the calling terminal. That, when the ISPBX/LAN Operator or ISPBX/LAN Extension answers the call, the ISPBX/LAN should return the appropriate signal to cause cha
26、rging to the ISDN. Handling of Outgoing Calls That at the start of a basic call the ISPBX/LAN should signal to the ISDN: (a) The called partys address. When the ISPBX/LAN knows that all address digits have been forwarded to the ISDN and indication of this shall also be forwarded, when required; (b)
27、the type of service required, e.g. Teletex; (c) the identity of the channel to be used, as appropriate to paragraph 7.1.1.; (d) the date rate of the originating terminal (CCITT XI rates); (e) the type of connection required, e.g. an all digital connection may be required in which some aspects of the
28、 quality of the connection may be specified, e.g. the error rate or maximum propagation time; (0 the identity of the calling extension or ISPBX/LAN (if and when required). CHARGING FOR SUCCESSFUL CALLS TO ISPBXslLANs DDI That in the case of DDI, the call should be charged or logged in the network ei
29、ther i) when a call has successfully reached the destination extension, i.e. the method that is commonly used U) when a call is delivered accross the interface between the ISDN and a privately supplied ISPBX/LAN. Further study is required, in particular item ii) in relation to International calls. N
30、on DDI That in the case of Non-DDI ISPBXs/LANs a call is considered to have successfully reached the destination when it has reached the PBX operator function. (The operator function contains everything that is stated in paragraph 7.2.3.) at present or COMPATIBILITY CXECKTNG FOR ISPBXs/LANs A check
31、of the services, actually supported by an ISPBX/LAN extension, against the service indication of an incoming call, should be performed by the ISPBX/LAN. GENERATION OF SERVICE INDICATORS That the service indicator could be generated by either the ISPBX/LAN or the terminal as specified by the Administ
32、ration. POWER FAILURE That it should be possible even under local power failure conditions to accept and originate telephone calls and to support and alarm (warning) service from certain nominated extensions. I I i Edition of November 15, 1986 , _ TJSF 45 E Page 2 12. 12.1. 12.2. 12.3. 12.4. ,CEPT T
33、/SF*45*E 86 2326414 0009397 9 M OTHER ISPBX/LAN FUNCTIONS WITH ISDN IMPLICATIONS ISPBX/LAN Failure That in the event of an ISPBX/LAN failure, provision of emergency ser-* is the respons.-ility of whoever has responsibility for maintenance of the ISPBX/LAN (this may be either the Administration or Pr
34、ivate Industry). When ISPBX/LAN Maintenance is not the responsibility of the Administration, the Administra- tion could give assistance within limits, e.g. activation of By-pass numbers if provided. Operator Intrusion That the ISPBX/LAN may provide additional services on some calls to meet subscribe
35、r requirements, e.g. Operator Intrusion. However, these activities should be restricted to voice calls so that non-voice calls or calls with non-voice elements (e.g. Data and Voice-Data) are not degraded by an inappropriate ISPBX/ LAN action. Call Transfer That the handling of call request for call
36、transfers between ISPBX/LAN extensions should take account of compatibility between the transferred call and the designated extension terminal. This is an ISPBX/LAN function. Source of Supplementary Services That it should be possible for extension users to be advised of the source of Supplementary
37、Services (ISPBX/LAN or Network) if it is advisable on operational grounds.” Edition of November 15, 1Ya6 CEPT T/SF*45*E 86 2326414 0009398 O T/SF 45 E Annex A, Page 1 Annex A List of standardized teleservices for the ISDN that may be available for ISPBXs/LANs The standardized teleservices that may b
38、e available to ISPBXs/LANs are summarised below: Telephone Teletex Facsimile Videotex Requirements for each standardized service will be specified separately. The ISPBXs/LANs should make it possible to allow access to the telex network via the ISDN. A list of other services that are currently provid
39、ed using standardized services and/or existing networks is included at Annex D. These services are not standardized services, or Supplementary Services but, nevertheless, their provision by ISPBXs/LANs should not be overlooked. Edition of November 15, 1986 CEPT T/SF*45*E b m 232bYL4 O009399 2 m _ T/
40、SF 45 E Annex B, Page 2 Annex B Existing telecommunication services to be supported by ISPBXs/LANs This Annex contains a list of services that are currently provided by use of existing networks. The support of these services by ISPBXs/LANs requires further study. It is also necessary to determine th
41、e relationship between these services and the definitions of bearer, tele- and Supplementary services (see Annex A of SF ISDN Recommendation). The services so far identified are: - Switched telephone access to public radiophone. - Access to public radiopaging. - Data by telephone. - Facsimile for telephone. - Videotex by telephone. O Edition of November 15, 1986
