WPCL 2BJ|x ` H(   x|@  6'6' Recommendation I.241 Teleservices supported by an ISDN HRecommendation I.210 describes the principles for defining telecommunication services supported by an ISDN including the concept of bearer services, teleservices, and supplementary services. It also provides the means for the definition and description of such services.   HIn Recommendation I.240, six teleservices are identified to be supported by an ISDN, i.e., Telephony, Teletex, Telefax 4, Mixed mode, Videotex and Telex. HThis Recommendation contains the service descriptions for these teleservices. Descriptions for other teleservices are for further study. The description of teleservices is structured in accordance with the three steps in stage 1 of the service description method.   HThe recommended support for these teleservices is given in section 7.2 of each individual service description. I.241.1 Telephony 1.HDefinition HThe "Telephony Service" provides users with the ability for realtime twoway speech conversation via the network. 2.HDescription 2.1HGeneral description HThe "Telephony service" provides speech transmission at an audio bandwidth of 3.1 kHz. The communication is bidirectional, with both directions continuously 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. HThe digital signal at the S/T reference point follows the encoding laws for speech (according to Recommendation G.711), Alaw or law and 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 Dchannel. Tones and announcements are provided by the network, encoded according to Recommendation G.711, although terminals can generate tones or other indications based on the messages received. 2.2HSpecific terminology Ha)h  Voice quality   HHX The required acoustic performance is described in terms of loudness ratings, frequency response, quantizing distortion, etc. Overall requirements are given in the Recommendations in the PSeries.  `  Hb)h  Transmission delay   HX 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. Hc)h  Retention Timer  H HX 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. 3.HProcedures 3.1HProvision/withdrawal 3.1.1HProvision of this service will be by prearrangement with the administration/RPOA. 3.1.2HThe teleservice is offered with several subscription options which apply separately to each ISDN number or group of ISDN numbers on the interface. For each subscription option, only one value can be selected. Subscription options for the interface are summarized below: Subscription Option(++,Value Maximum number of information(+m, where m is not greater channels available at user B(+than the number of H (+information channels on the H (+interface Maximum number of total calls(+n, where n is not greater present at user B(++,than the number of H (+information channels on the H (+interface   HUser B can be an ISDN number or group of ISDN numbers on the interface. Note More than one ISDN number can be associated with the service/interface only as a 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 network provider option, separate values may be specified for incoming and for outgoing calls for either or both of the limits. 3.2HNormal procedures Ha)h  Originating the service (call set up) HThe service is originated by the originating user activating the terminal, performing service selection if applicable for the originating terminal, and terminating customer selection. During this process the originating user is given appropriate indications as to the state of the call. H 1)ha service selection is required on a multiservice terminal; H 2)hterminating customer selection is selecting the required termination (user/network interface) by an appropriate means (for example, the use of DDI, or multiple subscriber number); H 3)hindications 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 possible to have audible , indications which may be accompanied by other indications. Hb)h  Call acceptance (answer) HSelection 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, i.e., answer, causes the indications to be removed and bidirectional communication paths to be provided. The call is now termed in the "speech phase". Hc)h  Call release HA 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. Hd)h  Failure situations due to user error HX The following failure situations may occur due to user error: H 1)huser taking too long to input the network address information will be given as a failure indication, e.g. during overlap sending (see Recommendations I.451 and I.220); H 2)huser inputting a non valid network address, e.g. an unallocated address, will be given a failure indication. He)h  Failure indications due to terminating termination state H 1)hUser attempting to set up a call to a termination where no free B channels are available will receive a busy indication unless call waiting or another supplementary service is in operation (Note 1). Note 1 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 to know when a channel is busy with telephony. H 2)hUser attempting to set up a call to a termination where the call is not accepted, i.e. no response indicating call acceptance is received, will after a defined period be given a call failure indication. (See Recommendations I.451 and I.220). Hf)h  Failure situations due to network conditions H 1)hUser attempting to set up a call but meeting problems in the network (e.g. congestion) will be given a suitable indication. 4.HNetwork capabilities for charging HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements 5.1HInterworking is required between the ISDN and PSTN. 6.HInteraction with supplementary services HNot applicable. Each supplementary service description identifies the applicability with this teleservice. 7.HAttributes/values 7.1Ha)h  Low layer attributes HX Information transfer attributes H 1.hInformation transfer mode: Circuit H 2.hInformation transfer rate: 64 kbit/s H 3.hInformation transfer capability: Speech H 4.hStructure: 8 kHz integrity H 5.hEstablishment of communication: on demand H 6.hCommunication configuration: Pointtopoint H 7.hSymmetry: Bidirectional symmetric HAccess attributes HX Access channel (and rate): B(64) for user information, D for signalling (Note 2) H 9.1Signalling access protocol layer 1: I.430/I.431 H 9.4Information access protocol layer 1: I.430/I.431; G.711 H 9.2Signalling access protocol layer 2: I.440/I.441 H 9.5Information access protocol layer 2: H 9.3Signalling access protocol layer 3: I.450/I.451 H 9.6Information access protocol layer 3: Note 2 For reserved/permanent service the operational, administrative and maintenance message related to these services may be conveyed over the Dchannel. Hb)  Higher layer attributes H 10.Type of user information: Speech H 11.Layer 4 protocol functions: H 12.Layer 5 protocol functions: H 13.Layer 6 protocol functions: G.711 H 14.Layer 7 protocol functions: Hc)  General attributes H 15.Supplementary services provided:FS H 16.Quality of Service: FS H 17.Interworking possibilities: to and from PSTN H 18.Operational and commercial: FS H Not applicable H FS for further study 7.2HTelephony supported by an ISDN HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E (essential) and A (additional) can be found in RecommendationI.240. Ha)h  Overall support: E/A (Note 3) HVariations of nondominant attributes:   b1) Information transfer mode  Support  ,Ԍ  circuit  E   b2)  Establishment  Symmetry Communication  Support   of communication  configuration     demand   ptpt  E   reserved Bidirectional  ptpt  FS   permanent  Symmetric  ptpt  A        demand   multipt  A   reserved Bidirectional  ptpt  FS   permanent  Symmetric  multipt  A    Hb3)  Access: HH  ` $   $  Signalling and OAM User information  Support  $  (Note 4)    $  $  Channel  Protocols Channel Protocols   $  and rate  and rate    $ $  D(16) I.430, I.440,  B(64) I.430,  E  $  I.441, I.450,  G.711   $  I.451 (Note 5)     $       $  D(64) I.431, I.440,  B(64) I.431,  E  $  I.441, I.450,  G.711   $  I.451 (Note 5)     $   Note 3 It is anticipated that ISDNs offer telephony as a basic telecommunication service. Some networks will offer this as a teleservice. However, due to national regulation policies some networks will offer telephony as a bearer service rather than as a teleservice. Note 4 Definition of protocols for OAM are FFS. Note 5 Demand services only. Others are FFS. 8.HDynamic description   HThe circuitmode dynamic description appears in RecommendationI.220. I.241.2 Teletex HThe prose description of the Teletex service is an extract of Recommendation F.200. If more detail is required this Recommendation should be referred to. As such, this service description does not strictly follow the substeps for step 1.1 of the service description method. Further alignment with the substeps requires further study. 1.HDefinition HTeletex is an international service, enabling subscribers to exchange office correspondence in the form of documents containing Teletex coded information on an automatic memorytomemory basis via the ISDN. 2.HDescription 2.1HScope HThe Teletex service provides communication between Teletex equipment* which are used for the preparation, editing and printing of correspondence containing text information using a standardized character set (RecommendationT.61).  *Teletex equipment may be a Teletex terminal or a system. HThe basic element of the correspondence between people using the service is the page, as the smallest unit of text treated as an entity. No restrictions shall exist as far as the operator procedures for generation of the text or the positioning of text within the printable area on a page are concerned.  h Note 1 This does not necessarily imply that the characters used to construct a graphic symbol are transmitted in the same sequence as that in which they are keyed. Note 2 This does not necessarily imply that the order in which text on a page is transmitted is the same as that in which it was keyed. Note 3 An exception to this rule is the application of the processable mode of operation for which the page as a basic element of correspondence cannot be used. The processable mode of operation within the Teletex service is defined in Recommendation F.220. 2.2HOperation 2.2.1HGeneral HThe Teletex service in each country and the international interconnection between countries or networks shall use automatic switching so that it is possible for any Teletex subscriber to reach any other Teletex subscriber using fully automatic selection. HIt is a requirement to allow the throughconnection of a call between a Teletex terminal connected to a private automatic branch exchange (or similar systems) and those connected to public exchanges used for the Teletex service. HA virtual dialogue mode of operation, which appears to the subscriber as an interactive mode should be possible, although this is not a basic requirement of the Teletex service. HA virtual dialogue mode of operation, which appears to the subscriber as an interactive mode may become possible as a new standardized option within the Teletex service, both allowing communications between persons and data base access (refer to Recommendation I.210). HProcessable mode of operation, as a standardized option within the Teletex service, allows the transfer of text containing information to permit convenient further editing and processing by the recipient (refer to Recommendation F.220). HMixed mode of operation using the techniques of Telefax 4 for the transfer of facsimilecoded information and of Teletex for the transfer of charactercoded , text is described as a standardized option within the Teletex service in Recommendation F.230. HTwoway alternate (TWA) communication is a capability of the Teletex service, which also includes oneway communication (OWC); the calling subscriber will have full control of the Teletex call. 3.HProcedures 3.1HProvision/withdrawal HThe national and international facilities of the Teletex service, including the Teletex/telex conversion facilities, shall be open continuously. HTeletex subscriber equipment for which call numbers are published in the directories shall, in principle, be available to accept calls continuously. HIn order to facilitate the twentyfour hour duration of the service it is permitted to use a centralized storage in the network to realize receiving memory capability of the terminal. 3.2HCall phases HThe operations for each call may be divided into the following three phases: Ha)h  Preparation H  preparation of the information in local mode; H  loading of the information into a memory, Hb)h  Transmission (in principle, automatic) H  call establishment; H  preinformation phase (see note); H  information transfer from memorytomemory (see note); H  post information phase (see note); H  call clearing. Note During these parts of the transmission phase the network must be transparent with respect to control procedures. Hc)h  Output H  emptying the memory. Note The information may consist of one or more Teletex documents each consisting of one or more Teletex pages. HThe control procedures as specified in Recommendation T.62 shall be used as endtoend communication procedures between any Teletex equipment in the basic service. HThe lower layer protocols and the network independent basic transport protocol to be used for Teletex are specified in RecommendationsT.70 and T.90. HThe networkdependent control procedures for the Teletex are those that are defined for ISDN. 3.3HCall identification line HThe Teletex procedures include the exchange of reference information prior to sending any document. This reference information includes identification of the parties to the call as well as the date and time. Also, supplementary reference information is exchanged during a call to allow reference to an individual document or page for error recovery or other purposes. HThis reference information, taken together, is defined to be printable on a single line called the call identification line. The use of this information is a local decision except in recovering from an interrupted transmission. HThe Call Identification Line is composed of four fields as follows: H Field 1: identification of the called Teletex equipment; H Field 2: identification of the calling Teletex equipment; H Field 3: date and time; H Field 4: supplementary reference information. 8,   8,  Field 1   Field 2   Field 3   Field 4  8,    8,  Identification   Identification  Date and time  Supplementary  8,  of the called /  of the calling /  /  reference  8,  Teletex equipment  Teletex equipment     information  8,    8,  24 characters 1 24 characters 1 14 characters 1  7 characters  8,         < 72 Characters >  T180703088 HField 1 (identification of the called equipment) contains the identification of the called equipment. It is originated in the control procedures by the called equipment. HField 2 (identification of the calling equipment) contains the identification of the calling equipment. It is originated in the control procedures by the calling equipment. HField 3 (date and time) contains the date and time reference information showing the year, month, day, hour and minute in the fixed format of 14characters thus YYMMDDHH:MM. This field is originated in the control procedures by the calling equipment which obtains this information from the network. This time represents the local time at the calling equipment and is intended to represent the time of call origination. HField 4 (supplementary reference information) contains a document reference number, a hyphen (coding 2/13) as a separator and a page reference number as defined in Recommendation T.62. This field has a fixed length of seven character positions and is originated in the control procedures by the Teletex equipment that is sending the associated documents. 8JFIGURE 1/I.241.2 8R 8?Format of the Call Identification Lineă  ,Ԍ3.4HError protection HWithin the Teletex service a high layer error detection and correction is provided in the session layer for all those errors which are not corrected by the network layers. HTo ensure call integrity, error protection will be provided by Teletex control procedures (see Recommendations T.62, T.70 and T.90). The error rate on the preinformation, information and postinformation phases should not exceed 1 in 106 characters. 4.HNetwork capabilities for charging HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements 5.1HWithin the Teletex service interworking between terminals connected to different networks is required. Realtime connection between terminals operating at different speeds has to be provided on the basis of at least 2.4kbit/s. 5.2HIntercommunication with other services 5.2.1HThe Teletex service will provide the ability to intercommunication both directions with the telex service by means of conversion facilities (refer to RecommendationsF.201, U.201, T.390). 5.2.2HIntercommunication between basic mode and mixed mode Teletex terminals and ClassesI, II and III Group4 facsimile terminals is shown in Table1 (refer to Recommendation F.184). 5.2.3HThe Teletex service allows for intercommunication with telex and with Interpersonal Messaging Service (IPM) (Ref. to F.421, F.422). 8KTABLE 1/I.241.2 8R 85Current status of direct intercommunication for Teletex andă 8;Group 4 facsimile terminals on the same networkă 8R 8R    To Facsimile  Facsimile  Facsimile  Teletex  Teletex  Teletex   Group 4  Group 4  Group 4  basic  mixed  Processable   From Class I  Class II  Class III  mode  mode  Mode 1   Facsimile        Group 4  F  F  F     Class I         Facsimile        Group 4  F  F  F     Class II         Facsimile        Group 4  F  T, F, MM  T, F, MM  T  T, MM  T  Class III         Teletex        basic   T  T  T  T  T  mode         Teletex        mixed  T, MM T, MM  T  T, MM  T  mode         Teletex        Proces   T  T  T  T  T, PM1  sable        Mode 1          T:XHBasic Teletex document with character coded information only. F:XHGroup 4 Facsimile document with facsimile coded information only. MM:HMixedmode document with character and facsimile coded information. PM1:hHProcessable mode document with character coded information only. 6.HInteraction with supplementary services HEach supplementary service description identifies the applicability with this teleservice. HFor the ISDN, the international supplementary services which may be used for Teletex in the circuit mode using a B Channel: Hi)h  Closed User Group; Hii)  Multiple Subscriber Number; HHX HHiii) UsertoUser Signalling; Hiv)  Calling Line Identification Presentation; Hv)h  Calling Line Identification Restriction; Hvi)  Connected Line Identification Presentation; HHX HHvii) Connected Line Identification Restriction; HHX HHviii) Direct Dialling In; HThe use of other supplementary services is for further study. HSupplementary Services for Teletex with packet mode of operation are for further study. 7.HAttributes/values 7.1Ha)  Low layer attributes HInformation transfer attributes Circuit mode bearer Packet mode bearer capability capability 1. Mode: Circuit Packet 2. Rate: 64 kbit/s Maximum throughput of a given virtual circuit is  ,Ԍ less than or equal to the maximum bit rate of the user information access channel and the throughput class of the virtual circuit. 3. Info transfer Unrestricted (Note 4) Unrestricted cap: 4. Structure: Unstructured (Note 5) Service data unit integrity 5. Establishment: Demand Demand (VC), permanent (PVC) 6. Configuration: Pointtopoint Pointtopoint 7. Symmetry: Bidirectional symmetric Bidirectional symmetric Access attributes Circuit mode bearer Packet mode bearer capability capability 8. Access B Channel User information over channel: (B for user info. virtual circuit within B or D for signalling) D Channel. When D Channel is used, maximum packet size and quality of service may be restricted. Signalling may be provided via D and/or virtual circuit within B Channel. 9.1 Signalling I.430/I.431 I.430/I.431 access protocol layer 1: 9.2 Signalling I.440/I.441 I.440/I.441, X.31 access protocol layer 2: 9.3 Signalling I.450/I.451 I.450/I.451, X.31 access protocol layer 3: 9.4 Information I.430/I.431 I.430/I.431 access protocol layer 1: 9.5 Information X.75 (SLP) X.25 LAP B access protocol layer 2: 9.6 Information ISO 8208 X.25 (PLP) access protocol layer 3: Note 4 The interworking arrangements with networks having restricted 64kbit/s information transfer capability require further study. Note 5 Even if no structure is required the network may provide 8kHz integrity. Hb)  High layer attributes H10. Type of user info: Teletex H11.  Layer 4 protocol: T.70 H12.  Layer 5 protocol: T.62 H13.  Layer 6 protocol: T.61 H14.  Layer 7 protocol: T.60 Hc)  General attributes H15.  Supplementary services provided: See subsection 6/I.241.2 H16.  Quality of service: FS H17.  Interworking possibilities: See subsection 5/I.241.2 H18.  Operational and commercial: FS SLP Single Link Protocol PLP Packet Layer Protocol 7.2HTeletex supported by an ISDN HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E (Essential) and A (Additional) can be found in RecommendationI.240. Ha)  Overall support: A Hb)  Variations of nondominant attributes: b.1) Information transfer mode (Note 6)  Support  circuit  A packet  A  b.2) Establishment Symmetry Communication  Support of communication configuration   demand bidirectional ptpt  E symmetric    b.3) Access:    Signalling & OAM  User information  Support (Note 7)     Channel   Channel   & rate  Protocols  & rate  Protocols   Circuit mode D(16)  I.430, I.440, I.441,  B(64)  I.430,  A  I.450, I.451 (Note 8)   X.75 (SLP),     ISO 8208      ,Ԍ D(64)  I.431, I.440, I.441,  B(64)  I.431,  A  I.450, I.451 (Note 8)   X.75 (SLP),     ISO 8208   Packet mode D(16)  I.430, I.440, I.441,  B(64)  I.430,  A  I.450, I.451, X.31  of  X.25 LAP B,    D(16)  X.25 (PLP)      D(64)  I.431, I.440, I.441,  B(64)  I.431,  FS  I.450, I.451, X.31   X.25 LAP B,     X.25 (PLP)      VC in  FS  B(64)  FS  FS B(64)      Note 6 In the interim period the circuitmode method of operation is preferred. Note 7 Definition of protocols for OAM are FFS Note 8 Demand services only. Other are FFS. 8.HDynamic description HThe circuitmode dynamic description appears in RecommendationI.220. I.241.3 Telefax 4 HThe prose description of the Telefax 4 service is an extract of RecommendationF.184. If more detail is required this Recommendation should be referred to. As such this service is not strictly structured a wording to the substeps for Step1.1 of the service description method. Further alignment with the substeps requires further study. 1.HDefinition HTelefax4 is an international service enabling subscribers to exchange office correspondence in the form of documents containing facsimile coded information automatically via the ISDN. 2.HDescription 2.1HGeneral description HThe Telefax 4 service provides a basic level of compatibility between all terminals participating in the service. It offers bidirectional communication between two users via the ISDN using 64kbit/s digital signals over the B channel. HThere are three classes of Group4 facsimile terminals:  H HHClass I minimum requirement terminal is a terminal able to send and  receivedocuments containing facsimile encoded information (+(in accordance with RecommendationsT.6 and T.400Series).  `    HHClass II minimum requirement terminal is a terminal able to transmit  documents that are facsimile encoded (in accordance with RecommendationsT.6 and T.400Series). In addition, the (+terminal must be capable of receiving documents which are /0facsimile coded (in accordance with RecommendationsT.6 and 67T.400Series), teletex coded (in accordance with the basic <=coded character repertoire and defined in 01RecommendationT.61) and also mixedmode documents (in 23accordance with Recommendationsof the T.400Series).  `    HHClass III minimum requirement terminal is a terminal that is capable  of generating, transmitting and receiving facsimile coded (+documents (in accordance with RecommendationsT.6 and ,-T.400Series), teletex coded documents (in accordance with 23the basic coded character repertoire as defined in 1p2RecommendationT.61) and mixedmode documents (in 01accordance with Recommendationsof the T.400Series).  `    HThe basic element of the correspondence between people using the service is the page, as the smallest unit of text treated as an entity.  No restrictions shall exist as far as the operator procedures for generation of the text or the positioning of text within the reproducible area on a page are concerned. 3.HProcedures 3.1HProvision/withdrawal HThe national and international Telefax4 service shall be open continuously. HTelefax4 terminals for which call numbers are published in the directories shall, in principle, be available to accept calls continuously. HIn order to facilitate the 24 hour duration of service it is permitted to use a centralized storage in the network to realize receiving memory capability of the terminal. 3.2HGeneral HThe Telefax4 service in each country and the interconnection between countries or networks shall use automatic switching so that it is possible for any Telefax4 subscriber to reach any other Telefax4 subscriber using fully automatic selection. HIt is a requirement to allow the throughconnection of a call between Group4 facsimile terminals connected to a private automatic branch exchange (or similar systems) and those connected to public exchanges used for the Group4 facsimile service. HTwoway alternate (TWA) communication is a capability of the Telefax4 service, which also includes oneway communication (OWC); the calling subscriber will have full control of the Group4 facsimile call. 3.3HCall phases HThe operations for each call may be divided into the following three phases:   HHa)h  preparation: preparation of the information to be transmitted;  `  HHb)h  transmission: ,ƌ HHX © call establishment (automatic); HHX © preinformation phase (see Note); HHX © information transfer (see Note); HHX © post information phase (see Note); HHX © call clearing.   Note During these parts of the transmission phase the network must be transparent with respect to control procedures.  8 HHc)h  output: displaying the message either by immediate printing or from a storage medium upon control by the operator.  `   8 Note The information may consist of one or more Telefax4 documents each consisting of one or more Telefax pages. HThe control procedures as specified in the Recommendations of the T.400Series and T.62 shall be used as endtoend communication procedures between terminals in the service. HThe low layer protocols and the network independent basic transport protocol for Telefax4 are specified in Recommendations T.70 and T.90.   HThe network dependent control procedures for the Telefax4 service are those that are defined for ISDN. 3.4HCall identification HThe Telefax4 procedures include the exchange of reference information prior to sending any document. This reference information includes identification of the parties to the call as well as the date and time. Also, supplementary reference information is exchanged during a call to allow reference to an individual document or page for error recovery or other purposes. Date and time have to be provided by the network and sent to the calling terminal in the call set up phase. HThis reference information, taken together, is defined to be printable on a single line called the call identification line. Use of this information is a local decision except in recovering from an interrupted transmission. In the case of automatic linking, the use of this information is for further study. HFor the format of the call identification line: see RecommendationF.200. 3.5HError protection HTo ensure call integrity, error protection will be provided by Telefax4 control procedures (see RecommendationsT.62, T.70 and T.90). Besides the error detection and correction mechanism in the layer 2 (and 3) an additional error detection and correction mechanism is provided in the session layer. By this mechanism errors of the higher layer functions (e.g. command/response sequence error) and transmission errors, which are not corrected by the lower layers, will be corrected by e.g. retransmission of one or several pages. HThe error rate on the preinformation, information and postinformation phases should not exceed 1x10é6. 4.HNetwork capabilities for charging HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements 5.1HWithin the Telefax4 service interworking between terminals connected to different networks is required HHa)h  Telefax 4 (ISDN) Telefax 4 (CSPDN)  `  HHb)h  Telefax 4 (ISDN) Telefax 4 (PSPDN) HHc)h  Telefax 4 (ISDN) Telefax 4 (PSTN)  8 HIn the case of international interworking between Group4 facsimile terminals connected to dissimilar networks, RecommendationX.300 shall   apply. For international interworking between PSTN and ISDN, a (separate) Telefax4 interworking unit may be necessary. HInternational routes between ISDNs for the Telefax4 service shall be capable of supporting user data rates up to 64kbit/s. 5.2HIntercommunication with other services 5.2.1HIntercommunication between basic mode and mixed mode Teletex terminals and ClassesI, II and III Group4 facsimile terminals connected to the Telefax4 service is shown in Table1/I.241.3. HHTABLE 1/I.241.3 H,Current status possible cases of direct intercommunication for Teletexă H@and Group 4 facsimile terminalsă HFon the same networkă         Teletex   To Facsimile Facsimile Facsimile Teletex Teletex proces  From Group 4 Group 4 Group 4 basic mixed sable    Class I  Class II Class III mode mode Mode 1   Facsimile        Group 4  F  F  F     Class I         Facsimile        Group 4 F F F     Class II         Facsimile        Group 4 F T, F, MM T, F, MM T T, MM T  Class III         Teletex        basic  T T T T T  mode        ,Ԍ Teletex        mixed  T, MM T,MM T T,MM T  mode         Teletex        Processable   T  T  T  T  T, PM1  Mode 1          T: Basic Teletex document with character coded information only. F: Group 4 Facsimile document with facsimile coded information only. MM:Mixedmode document with character and facsimile coded information. PM1:Processable mode document with character coded information only. HIn both the Teletex and Telefax4 services, the equipment providing mixed mode should enable a direct exchange of documents in accordance with RecommendationsT.6, T.61 and T.400Series. 5.2.2HIntercommunication is desirable between terminals of the Telefax4 service and terminals of services other than Telefax 4 provided over ISDN and other public switched networks. HIntercommunication possibilities between Telefax4 terminals and Telefax3 terminals have to be provided (see also RecommendationF.180): HHa)h  Telefax 4 (ISDN) Telefax 3 (PSTN);  `    HHb)h  Telefax 4 (ISDN) Telefax 3 (ISDN, via terminal adaptors).  `   H HIn case a) Telefax4 terminals use specific service features in ISDN. Intercommunication should be supported by ISDNPSTN interworking units. HIn case b) Telefax3 terminals and Telefax4 terminals which are to be connected in the PSTN can also be connected to the ISDN via terminal adaptors. 6.HInteraction with supplementary services HEach supplementary service description identifies the applicability with this teleservice. HInternational supplementary services for the Telefax4 service in the circuit mode on a B channel: HHi)h  Closed User Group;  `  HHii)  Multiple Subscriber Number; HHX Hiii) User to User Signalling; HHiv)  Calling Line Identification Presentation; HHv)h  Calling Line Identification Restriction; HHvi)  Connected Line Identification Presentation; HHX Hvii) Connected Line Identification Restriction; HHX Hviii) Direct Dialling In.   HThe use of other supplementary services is for further study. Supplementary services for Telefax4 with packet mode of operation are for further study. 7.HAttributes/values 7.1Ha)  Low layer attributes HInformation transfer attributes    Circuit mode bearer Packet mode bearer capability capability 1. Mode: Circuit Packet 2. Rate: 64 kbit/s Maximum throughput of a given virtual circuit is less than or equal to the maximum bit rate of the user information access channel and the throughput class of the virtual circuit. 3. Info transfer Unrestricted (Note 3) Unrestricted cap: 4. Structure: Unstructured (Note 4) Service data unit integrity 5. Establishment: Demand Demand (VC), permanent (PVC) 6. Configuration: Pointtopoint Pointtopoint 7. Symmetry: Bidirectional symmetric Bidirectional symmetric Access attributes Circuit mode bearer Packet mode bearer capability capability 8. Access B Channel User information over channel: (B for user info virtual circuit within B or D for signalling) D Channel. When D Channel is used, maximum packet size and quality of service may be restricted. Signalling may be provided via D and/or virtual circuit within B Channel (Note 1). 9.1 Signalling I.430/I.431 I.430/I.431 access protocol layer 1: 9.2 Signalling I.440/I.441 I.440/I.441, X.31 access protocol layer 2: , Ԍ 9.3 Signalling I.450/I.451 I.450/I.451, X.31 access protocol layer 3: 9.4 Information I.430/I.431 I.430/I.431 access protocol layer 1: 9.5 Information X.75 (SLP) X.25 LAP B access protocol layer 2: 9.6 Information ISO 8208 X.25 (PLP) access protocol layer 3: Hb)  High layer attributes H10. Type of user info: Teletex H11.  Layer 4 protocol: T.70 H12.  Layer 5 protocol: T.62 H13.  Layer 6 protocol: T.400Series (Note 2) H13.1Resolution [ppi]: 200 x 200 standard; H 240 x 240, 300 x 300, 400 x 400 optional H14.  Layer 7 protocol: T.503, 521, 563 Hc)  General attributes H15.  Supplementary services provided: see section 6/I.241.3 H16.  Quality of service: FS H17.  Interworking possibilities: see section 5/I.241.3 H18.  Operational and commercial: FS Note 1 User information transferred via virtual channel on the D Channel is for further study. Note 2 Further study is required to identify a more precise reference in the T.400Series of Recommendations.  h Note 3 The interworking arrangements with networks having restricted 64kbit/s information transfer capability require further study. Note 4 Even if no structure is required the network may provide 8kHz integrity. 7.2HTelefax 4 supported by an ISDN HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E (Essential) and A (Additional) can be found in RecommendationI.240. Ha)  Overall support: A Hb)  Variations of nondominant attributes: b.1) Information transfer mode (Note 5)  Support  circuit  A packet   b.2) Establishment  Symmetry  Communication  Support of communication   configuration   demand  bidirectional  ptpt  E  symmetric     b.3) Access:    Signalling & OAM  User information  Support (Note 6)    Channel   Channel   & rate  Protocols  & rate  Protocol      Circuit mode       D(16)  I.430, I.440, I.441,  B(64)  I.430,  A  I.450, I.451 (Note 7)   X.75 (SLP),     ISO 8208      D(64)  I.431, I.440, I.441,  B(64)  I.431,  A  I.450, I.451 (Note 7)   X.75 (SLP),     ISO 8208   Packet mode D(16)  I.430, I.440, I.441,  B(64)  I.430,  A  I.450, I.451, X.31  or  X.25 LAP B,    D(16)  X.25 (PLP)      D(64)  I.431, I.440, I.441,  B(64)  I.431, ...  FS  I.450, I.451, X.31            VC in  FS  B(64)  FS  FS B(64)      Note 5 In the interim period the circuit mode method of operation is preferred. Note 6 Definition of protocols for OAM is for further study. Note 7 Demand services only. Others are FFS. 8.HDynamic description HThe circuit mode dynamic description appears in RecommendationI.220. I.241.4 Mixed mode HThe prose definition of the mixed mode service is an extract of Recommendation F.230. 1.HDefinition HThis service provides combined text and facsimile communication for endtoend transfer of documents containing mixed information of text and fixed images. ,  The high layer attributes are based on the CCITT Recommendations for Teletex amd Telefax 4. 2.HDescription HFor further study. 3.HProcedures HFor further study. 4.HNetwork capabilities for charging HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements HFor further study. 6.HInteraction with supplementary services HFor further study. 7.HAttributes/values 7.1Ha)  Low layer attributes HInformation transfer attributes Circuit mode bearer Packet mode bearer capability capability 1. Mode: Circuit Packet 2. Rate: 64 kbit/s Maximum throughput of a given virtual circuit is less than or equal to the maximum bit rate of the user information access channel and the throughput class of the virtual circuit. 3. Info transfer Unrestricted (Note 2) Unrestricted cap: 4. Structure: Unstructured (Note 3) Service data unit integrity 5. Establishment: Demand Demand (VC), permanent (PVC) 6. Configuration: Pointtopoint Pointtopoint 7. Symmetry: Bidirectional symmetric Bidirectional symmetric Access attributes Circuit mode bearer Packet mode bearer capability capability 8. Access B Channel User information over channel: (B for user info virtual circuit within B or D for signalling) D Channel. When D Channel is used, maximum packet size and quality of service may be restricted. Signalling may be provided via D and/or virtual circuit within B Channel (Note 1). 9.1 Signalling I.430/I.431 I.430/I.431 access protocol layer 1: 9.2 Signalling I.440/I.441 I.440/I.441, X.31 access protocol layer 2: 9.3 Signalling I.450/I.451 I.450/I.451, X.31 access protocol layer 3: 9.4 Information I.430/I.431 I.430/I.431 access protocol layer 1: 9.5 Information X.75 (SLP) X.25 LAP B access protocol layer 2: 9.6 Information ISO 8208 X.25 (PLP) access protocol layer 3: Hb)  High layer attributes H10. Type of user info:Mixed mode H11.  Layer 4 protocol: (+X.224, X.214 H12.  Layer 5 protocol: (+X.225, X.215 H13.  Layer 6 protocol: T.61, X.226, X.216X.226, X.216 H13.1Resolution [ppi]:300 x 300 H (+240 x 240 H (+400 x 400 optional, H (+600, 1200 H14.  Layer 7 protocol:T.501, T.522, T.561 Hc)  General attributes H15. Supplementary services provided: FS H16. Quality of service: FS H17. Interworking possibilities: ISDN Teletex, ISDN Telefax 4; H others: FS H18. Operational and commercial: FS Note 1 User information transferred via virtual channel on the D Channel is for ,  further study. Note 2 The interworking arrangements with networks having restricted 64kbit/s information transfer capability require further study. Note 3 Even if no structure is required the network may provide 8kHz integrity. 7.2HMixed mode supported by an ISDN HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E (Essential) and A (Additional) can be found in RecommendationI.240. Ha)  Overall support: A Hb)  Variations of nondominant attributes: b.1) Information transfer mode  Support  circuit  A packet  A  b.2) Establishment  Symmetry  Communication  Support of communication   configuration   demand  bidirectional  ptpt  E  symmetric   b.3) Access:   Signalling & OAM  User information  Support (Note 4)    Channel   Channel   & rate  Protocols  & rate  Protocols   Circuit mode D(16)  I.430, I.440, I.441,  B(64)  I.430,  A  I.450, I.451 (Note 5)   X.75(SLP),     ISO 8208      D(64)  I.431, I.440, I.441,  B(64)  I.431,  A  I.450, I.451 (Note 5)   X.75(SLP),     ISO 8208   Packet mode D(16)  I.430, I.440, I.441,  B(64)  I.430,  FS  I.450, I.451, X.31  or  X.25 LAP B,    D(16)  X.25(PLP)      D(64)  I.431, I.440, I.441,  B(64)  I.431, ...  FS  I.450, I.451, X.31        VC in  FS  B(64)  FS  FS B(64)      Note 4 Definition of protocols for OAM are FFS. Note 5 Demand services only. Others are FFS. 8.HDynamic description HThe circuit mode dynamic description appears in Recommendation I.220. I.241.5 Videotex HThe prose description for the Videotex service in ISDN is for further study and is intended to be based on Recommendation F.300. 1.HDefinition HThe Videotex service in the ISDN is an enhancement of the existing Videotex service with retrieval and mailbox functions for text (alpha) and graphic information. 2.HDescription HFor further study. 3.HProcedures HFor further study. 4.HNetwork capabilities for charging HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements HFor further study. 6.HInteraction with supplementary services HFor further study. 7.1HAttributes/values HHa)  Low layer attributes  `  HHInformation transfer attributes    Videotex centre to User to Videotex Videotex centre, centre external computers    HH1.  Mode:Circuit (Note 1)  Circuit/packet  p H2.  Rate:64 kbit/s  FS H3.  Info transfer cap.:unrestricted  FS H4.  Structure:FS  FS  ( H5.  Establishment:Demand  Demand/permanent H6.  Configuration:Pointtopoint  Pointtopoint,  multipoint , Ԍ  H7.  Symmetry:Bidirectional  Bidirectional symmetric  symmetric HAccess attributes H8.  Access channel: B for user info (Note 2), D for signalling H9.  Signalling a.p. layer 1: I.430/I.431 H9.1  Signalling a.p. layer 2: I.440/I.441 H9.2  Signalling a.p. layer 3: I.450/I.451 H9.3  Information a.p. layer 1: I.430/I.431 H9.4  Information a.p. layer 2: X.75 (SLP) H9.5  Information a.p. layer 3: ISO 8208 Hb)  High layer attributes H10.  Type of user info: Videotex H11.  Layer 4 protocol: H12.  Layer 5 protocol: H13.  Layer 6 protocol: FS H13.1 Resolution [ppi]: 13.2 Graphic mode: H14.  Layer 7 protocol: HHc) General attributes: FS  `  Note 1 The use of packet mode is for further study.   Note 2 The use of the D Channel for Videotex information is for further study. 7.2HVideotex supported by an ISDN  X HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E(Essential) and A(Additional) can be found in RecommendationI.240. HHa) Overall support: A  `  HHb) Variations of nondominant attributes:  p Рb.1)Information transfer mode Support  circuit user terminaltoVideotex centre A    (  videotex centre to Videotex centre, A external computer    packet Videotex centre to Videotex centre, A external computer      b.2)Establishment Symmetry Communication Support of communication  configuration   demand bidirectional ptpt E permanent (Note 3) symmetric      demand bidirectional multipoint A permanent (Note 3) symmetric  (Note 3)   b.3)Access: Signalling & OAM   (Note 4) User information Support     Channel  Channel   & rate  Protocols & rate Protocols   Circuit mode       D(16)  I.430, I.440, I.441 B(64) I.430 A  I.450, I.451 (Note 5)   X.75(SLP),    ISO 8208      D(64) I.431, I.440, I.441 B(64) I.431,  I.450, I.451 (Note 5)   X.75(SLP), A   ISO 8208   Packet mode       D(16) FS B(64) FS FS   or    D(16)       D(64) FS B(64) FS FS         VC in FS B(64) FS FS B(64)      Note 3 Between Videotex centres and to external computers. Note 4 Definition of protocols for OAM are FFS. Note 5 Demand services only. Others are FFS. 8.HDynamic description HThe circuit mode dynamic description appears in RecommendationI.220. I.241.6 Telex 1.HDefinition HThis service provides interactive text communication. The digital signal at the S/T reference point follows the internationally agreed Recommendations for telex above the ISDN physical layer. 2.HDescription HFor further study. 3.HProcedures HFor further study. 4.HNetwork capabilities for charging , Ԍ HThis Recommendation does not cover charging principles. Future Recommendations in the DSeries are expected to contain that information. It shall be possible to charge the subscriber accurately for the service. 5.HInterworking requirements HFor further study. 6.HInteraction with supplementary services HFor further study. 7.HAttributes/values 7.1Ha) Low layer attributes HHInformation transfer attributes  `    HH1.  Information transfer mode: circuit; packet is FFS (Note 1)  ` H2.  Information transfer rate: 64kbit/s H3.  Information transfer capabilitiy: unrestricted H4.  Structure: 8kHz integrity H5.  Establishment of communication: reserved/permanent H6.  Communication configuration: pointtopoint H7.  Symmetry: bidirectional HAccess attributes  8 H8.  Access channel: B/user information, D/signalling, D/telex user H information is FFS (Note 1) H9.1 Signalling a.p. layer 1: I.430/I.431 H9.2  Signalling a.p. layer 2: U.202 H9.3  Signalling a.p. layer 3: U.202 H9.4  Information a.p. layer 1: I.430/I.431 H9.5  Information a.p. layer 2: U.202 H9.6  Information a.p. layer 3: FS Hb)  High layer attributes H10.  Type of user information: Telex H11.  Layer 4 protocol: H12.  Layer 5 protocol: H13.  Layer 6 protocol: H14.  Layer 7 protocol: HHc) General attributes  `  H15.  Supplementary services provided: FS H16.  Quality of service: FS  p H17.  Interworking possibilities: Telex, Teletex, others: FS H18.  Operational and commercial: FS   Note 1 Subject to satisfying telex quality of service on Dchannel. 7.2HTelex supported by an ISDN  X HIn the following table the recommended overall support, and recommended support for the variations of the nondominant attributes are given. The definition of E(Essential) and A(Additional) can be found in RecommendationI.240. HHa) Overall support: FS  `  HHb) Variations of nondominant attributes:  p Рb.1)Information transfer mode Support  circuit FS packet FS     b.2)Establishment Symmetry Communication Support of communication     demand bidirectional ptpt E reserved symmetric ptpt FS permanent  ptpt A    demand bidirectional multipt A reserved symmetric multipt FS permanent  multipt A  b.3)Access: Signalling & OAM   (Note 2) User information Support     Channel  Channel   & rate  Protocols & rate Protocols   Circuit mode       D(16)  I.430, I.440, I.441 B(64) I.430 FS  I.450, I.451 (Note 3)   U.202    (Note 4)      D(64) I.431, I.440, I.441 B(64) I.431,  I.450, I.451 (Note 3)   U.202 FS   (Note 4)   Packet mode       D(16) "(Note 1) D(16) FS FS  Note 2 Definition of protocols for OAM are FFS. Note 3 Layer 2 and 3 protocols are FFS. Note 4 Others are FFS. 8.HDynamic description HFor further study.