1、INTERNATIONAL TELECOMMUNICATION UNION)45G134 (b) the strategic and commercial importance of standardization of message handling services;(c) the urgent need for intercommunication arrangements for existing telematic services, and other serviceswith public message handling services;(d) the need for a
2、 clear distinction between the responsibilities to be allocated to service providers and those ofsubscribers and/or users;(e) the need for establishing international compatibility between different messaging systems;(f) the growth of the installed base of terminals and personal computers with the ab
3、ility to access messagehandling systems;(g) that several F-series Recommendations describe public message handling services;(h) that certain X, T and U-series Recommendations cover relevant aspects of systems used for the provisionof messaging services;(i) that Recommendations F.60 and F.69 define t
4、he service requirements for the telex service;(j) that Recommendation F.72 defines international telex store-and-forward;(k) that the U-series Recommendations define the technical requirements for the telex service;(l) that Recommendation U.204 defines the technical requirements for the intercommuni
5、cation between theIPM service and the telex service;unanimously declaresthat operational procedures for intercommunication between the public interpersonal messaging service and thetelex service shall be in accordance with this Recommendation.CONTENTS1 Scope2 Introduction3 Service outline4 Operation
6、al procedures4.1 IPM service to telex service direction4.2 Telex service to IPM service direction4.3 Construction of the IP-message_1)This Recommendation is the same as Recommendation F.75 of which only the title appears in Fascicle II.4.2 Fascicle II.6 - Rec. F.421Annex A AbbreviationsAnnex B Actio
7、ns to be taken by the PTLXAU/examplesAnnex C IPM message to telexAnnex D Telex message to IPM1 Scope1.1 This Recommendation describes the general, operational and service procedures for the provision ofintercommunication between the public interpersonal messaging service and the telex service.1.2 Th
8、e intercommunication is based on store-and-forward principles which allow users of one service to exchangemessages with the users of the other service.2 IntroductionThe IPM service is a messaging service which may be provided on a variety of networks and allows severalforms of addresses, whereas the
9、 telex service provides direct connection between subscribers in the telex network.Therefore, to match dissimilar characteristics of the two services, it is necessary to provide intercommunicationvia a public telex access unit (PTLXAU). In both IPM service to telex service, and telex service to IPM
10、servicedirections, the complete message is deposited in the PTLXAU for onward transmission.In general the selection procedures for the telex subscriber will be two-stage; however, where the destinationIPM service user is assigned a numeric address that is part of the national telex numbering plan of
11、 the destinationcountry, one-stage selection procedures may be used.3 Service outline3.1 Communication between subscribers of the telex service and the IPM service is on store-and-forward basis;thus conversational mode interworking between users is not applicable.3.2 Public access to the IPM service
12、 for telex subscribers and delivery of messages to telex subscribers from IPMservice users is provided by means of a PTLXAU.3.3 The PTLXAU belongs to the IPM service.3.4 In the IPM service to telex service direction, the IPM service retains the responsibility for the message untildelivery to the tel
13、ex subscriber has been completed.3.5 In the telex service to IPM service direction, the IPM service is responsible for the delivery of the message tothe IPM service user, once the input is completed under normal conditions.3.6 In both IPM service to telex service direction and telex service to IPM s
14、ervice direction, the internationalconnection should be via the international telex network, as shown in Figure 1/F.421.3.7 Where two Administrations offer an IPM service, the international boundary may be placed within the IPMservice by bilateral agreement. In this configuration, however, internati
15、onal telex connections should continue to beestablished via the international telex network.Fascicle II.6 - Rec. F.421 34 Operational procedures4.1 IPM service to telex service direction4.1.1 Messages from an IPM service user to a telex subscriber are sent as normal IP-message with the appropriateIP
16、M elements of service, in accordance with Recommendation F.420.4.1.2 When a message is received by the PTLXAU, the message content will be converted into the format andcharacter repertoire defined for the telex service. This may result in loss of information if the IPM service user does notconform t
17、o these defined rules.Note The conversion process may take place in the message transfer system (MTS) associated with thePTLXAU.4.1.3 The PTLXAU shall be responsible for the action to be taken for IPM elements of service received inaccordance with Recommendation F.420. Annex B shows examples of IPM
18、elements of service together with proposedactions to be taken by the PTLXAU.4.1.4 Call establishment by and delivery of the message to the telex subscriber should be in accordance withRecommendations F.72 and U.204.4.1.5 The IP-message sent to the called telex subscriber shall be preceded by a PTLXA
19、U identification. The contentof this identification is a national matter but should include the service code “CI”, the code expression “IPM”, and thetelex network identification code in accordance with Recommendation F.69, e.g. “CI IPM CH”.4.1.6 A general layout of an IP-message delivered to the tel
20、ex service is shown in Annex C.4.1.7 The elements of service related to the IP-message heading shall be converted into printable text. The languageof this text is a national matter. The PTLXAU shall transmit the originator O/R address to the called telex subscriber inthe form necessary for recall, i
21、n accordance with the indications of Table 2/F.421 (see example in Annex C).4.1.8 In order to help the telex recipients to recall the originator, the PTLXAU could transmit, as the first element ofthe message heading, some information as guidance. The contents of this field is a national matter, but
22、when usedshould be called “FOR RECALL” (see Annex C).4.1.9 Upon delivery of the message to the telex subscriber, a delivery notification should be sent back to theoriginating IPM service user if requested. In the event of non-delivery of the message to the telex subscriber, a non-delivery notificati
23、on shall be sent back to the IPM service user (unless the IPM user has requested prevention of non-delivery notification).4.2 Telex service to IPM service directionIn this direction, Administrations may implement either or both one-stage and two-stage call set-up procedures.4.2.1 One-stage selection
24、4.2.1.1 Where one-stage call set-up procedures are used, the number assigned to a user in the IPM service mustappear to be part of the national telex numbering plan.4.2.1.2 The length of the number assigned to the IPM service user shall be in accordance with the relevant U-seriessignalling Recommend
25、ations.4.2.1.3 The procedures for message transfer within the IPM service, e.g. mapping of the assigned number to an O/Raddress, are a national matter and not covered by this Recommendation.4.2.1.4 The call shall be established using normal telex call set-up procedures.4.2.1.5 The telex number recei
26、ved by the PTLXAU from the telex network shall be verified by the IPM service asbeing proper to a registered IPM service user. If the verification fails:a) where the PTLXAU is provided by the Administration which also provides all or part of the telex network,the service signal NP may be returned;b)
27、 where the PTLXAU is not provided by the Administration which also provides all or part of the telexnetwork, the procedures to be applied shall be in accordance with Recommendation F.74.4.2.1.6 The answerback returned to the calling telex subscriber at call establishment and also during the text inp
28、utstage shall contain the national telex number assigned to the IPM service user.4 Fascicle II.6 - Rec. F.4214.2.1.7 The call shall be cleared using normal telex call clearing procedures.4.2.1.8 When the message cannot be delivered to the IPM service user, a non-delivery notification shall be return
29、edto the telex subscriber. The procedures for establishing the calling telex address are specified in RecommendationU.204.4.2.1.9 The non-delivery notification returned to the originating telex subscriber should contain a referenceconsisting of the telex address of the IPM service user and time and
30、date of submission to the PTLXAU.4.2.1.10 The action to be taken when a non-delivery notification cannot be returned to the calling telex subscriber isfor further study.4.2.1.11 The format of notifications and the procedures for their delivery should be in accordance withRecommendation U.204.4.2.1.1
31、2 The use of IPM elements of service by the telex subscriber is for further study.4.2.2 Two-stage selection4.2.2.1 The telex subscribers shall use normal telex call procedures to access the PTLXAU which is allocated a telexnumber that is part of the national telex numbering plan of the country in wh
32、ich the PTLXAU is located.4.2.2.2 Procedures for access to the PTLXAU shall follow Recommendation U.204.4.2.2.3 A service identifier may be input before the O/R address(es) of the first message. It may allow theAdministrations to provide intercommunication with several services through only one PTLX
33、AU (see Tables 1/F.421,3/F.421 and Annex D).4.2.2.4 The PTLXAU shall be able to accommodate the following O/R address forms: Mnemonic O/R address; Terminal O/R address; Numeric O/R address;as specified in Recommendation F.401. The O/R address should be input in accordance with the requirements ofRec
34、ommendation U.204.It is the responsibility of the originating telex subscriber to be aware of the required attributes specific to thedomain of the called IPM service user. Each attribute of the O/R address shall be identified and delimited. Thecomplete O/R address shall be terminated with an end-of-
35、address (EOA) indicator.The structure of the service identifier and the address input is shown in Table 1/F.421.Each attribute of the address structure shall be contained in one line.Each address attribute and the service shall be identified by a code expression according to Tables 2/F.421 and3/F.42
36、1.4.2.2.5 Under normal conditions, the message input will be terminated by an end of message (EOM) or and end oftransmission (EOT) signal. In case where no EOM or EOT signal is received, the PTLXAU shall forward any inputreceived prior to call disconnect with the added text “THIS MESSAGE MAY BE INCO
37、MPLETE”. Annex D shows ageneral layout applicable in case of submission of message(s) to the PTLXAU by the telex subscriber.4.2.2.6 Except as defined in 4.2.2.5 above, the action to be taken when abnormal conditions are encountered duringmessage input shall be in accordance with Recommendation U.204
38、.Fascicle II.6 - Rec. F.421 5TABLE 1/F.421Telex service to IPM service address structureNote indicates optional attributes.TABLE 2/F.421Code expressions for address attribute identifiersNote 1 The symbol equals a space .Note 2 Allowed attribute values are specified in Recommendation F.401.Service id
39、entifierAddress attribute identifier .Address attribute identifier End of single O/R address (+)Next O/R address(es)Request for IPM elements of serviceEnd of address(es) (BT)Request for delivery notificationAddress attribute FormatCountry nameAdministration domain namePrivate domain nameOrganization
40、 nameOrganisation unit name(s)Personal name Surname Given name Initials Generation qualifier Common nameNumeric user identifierTerminal type and network addressfor telexteletexfascimilevideotexDomain defined attribute(s) Type ValueCTN ADM PRI ORG OUN SUR GIV INI GEN COM NUS TLX TTX FAX VTX DDT DDV 6
41、 Fascicle II.6 - Rec. F.421TABLE 3/F.421Code expression for the service identifier4.2.2.7 During the input stage of the address, the PTLXAU shall validate, as a minimum, the following O/R addressformats, as specified by the domain: The existence of mandatory attributes. The existence of non-allowed
42、attributes. The minimum and maximum allowed number of characters in each attribute. The existence of non-allowed characters in an attribute.Where applicable, the existence/non-existence of non-significant character(s) preceding or following theattribute values shall not prevent validation.Despite th
43、e acceptance by the PTLXAU of the submitted O/R address, there is no guarantee that the messagewill be subsequently delivered and, in this case, the originating telex subscriber will be charged for a message whichwas not delivered. It is therefore desirable that a means of verifying the existence of
44、 the O/R adress be provided and themethod of achieving this is left for further study.4.2.2.8 The service principles for delivery and non-delivery notifications should be in accordance withRecommendation F.72. The format of the notification messages is defined in Recommendation U.204. Deliverynotifi
45、cation may be requested as a code expression following the end of address signal.4.3 Construction of the IP-messageThe message received by the PTLXAU shall be delivered to the IPM user(s) in accordance with followingrules.4.3.1 P2 body partThe received message, excluding the recipient address(es), s
46、hall form the body of the IP-message. All thereceived characters shall be delivered except the WRU signals.4.3.2 Recipient O/R addressAll recognized O/R addresses shall be assumed as primary recipients. By default, these primary recipients willnot be disclosed to each other.4.3.3 Originator indicati
47、onThe calling telex subscriber address shall be converted by the PTLXAU into the format of a terminal O/Raddress and shall be placed in the originator indication element of service field.4.3.4 Subject indicationThe PTLXAU shall generate the element of service which will cause TELEX to appear in the
48、subject indicationelement of service field.4.3.5 IP-message identificationThe content of the message reference information returned to the calling telex subscriber shall also be used asthe unique identifier in the IP-message identification element of service field.4.3.6 Grade of delivery selectionTh
49、e PTLXAU shall set the grade of delivery selection element of service to the value URGENT.Service FormatInterpersonal messaging service IPMFascicle II.6 - Rec. F.421 74.3.7 Conversion prohibition in case of loss of informationThe use of the element of service conversion prohibition in case of loss of information is for furtherstudy.4.3.8 Disclosure of other recipientsThis element of service shall be set by the PTLXAU when the originating telex subscriber requests thedisclosure of other recip
