CONTENTS

 1     Introduction
 2     Scope and objective
 3     List of telecommunications services and specific user applications covered by codings
 4     General principles applicable to all services
 5     Impact of interworking situations
        5.1     Incoming calls from non-ISDNs
        5.2     BC and LLC application guidelines
 6     Request and recognition of a basic telecommunications service in an ISDN environment
        6.1     Request and recognition of a circuit-mode bearer service
                  6.1.1     Circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for speech information transfer
                  6.1.2     Circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service category
                  6.1.3     Circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for 3.1 kHz audio information transfer
                  6.1.4     Circuit-mode 64 kbit/s 8 kHz structured multi-use bearer service category
                  6.1.5     Circuit-mode multi-rate bearer service for an ISDN interface
        6.2     Packet-mode bearer services categories
                  6.2.1     Virtual call bearer services [support of X.25 terminal equipment allowing access to the ISDN virtual circuit service (case B of Recommendation X.31)]
                  6.2.2     Frame mode bearer services
        6.3     Request and recognition of a teleservice
                  6.3.1     Telephony teleservice (3.1 kHz bandwidth)
                  6.3.2     Teletex service (using circuit-mode bearer capability)
                  6.3.3     Telefax G4 service (using circuit-mode bearer capability)
                  6.3.4     ISDN syntax-based Videotex service
                  6.3.5     ISDN Videotelephony teleservice
                  6.3.6     Facsimile group 2/3 service
 7     Codings applicable to specific user applications
        7.1     Specific user applications of the circuit-mode 64 kbit/s unrestricted 8 kHz structured bearer service
                  7.1.1     Support of terminal adaptors V.110 and X.30
                  7.1.2     Support of terminal adaptors V.120
                  7.1.3     Support of X.25 terminal equipment allowing access to PSPDN via AU (case A of Recommendation X.31)
        7.2     Specific user applications of the circuit-mode 64 kbit/s 8 kHz structured bearer service category usable for 3.1 kHz audio information transfer
                  7.2.1     Voice-band data via modem
 8     Codings for calls originating in a PSTN
 9     Abbreviations