Integrated Services Digital Network (ISDN); Diversion Supplementary Services; Digital Subscriber Signalling System No. One (DSS1) Protocol; Part 1: Protocol Specification (V2.0.1)
This first part of EN 300 207 specifies the stage three of the diversion supplementary services for the pan-European Integrated Services Digital Network (ISDN) as provided by European public telecommunications operators at the T reference point or coincident S and T reference point (as defined in ITU-T Recommendation I.411 [9]) by means of the Digital Subscriber Signalling System No. one (DSS1). Stage three identifies the protocol procedures and switching functions needed to support a telecommunication service (see CCITT Recommendation I.130 [4]). In addition@ the present document specifies the protocol requirements at the T reference point where the service is provided to the user via an intermediate private ISDN. The present document does not specify the additional protocol requirements where the service is provided to the user via a telecommunications network that is not an ISDN. The diversion supplementary services comprise the following services: - Call Forwarding Unconditional (CFU) supplementary service; - Call Forwarding Busy (CFB) supplementary service; - Call Forwarding No Reply (CFNR) supplementary service; - Selective Call Forwarding Unconditional (SCFU) supplementary service - Selective Call Forwarding Busy (SCFB) supplementary service; - Selective Call Forwarding No Reply (SCFNR) supplementary service; - Call Deflection (CD) supplementary service. The CFU supplementary service enables a served user to have the network redirect to another user calls which are addressed to the served user's ISDN number. The CFU supplementary service may operate on all calls@ or just those associated with specified basic services. The served user's ability to originate calls is unaffected by the CFU supplementary service. After the CFU supplementary service has been activated@ calls are forwarded independent of the status of the served user. The CFB supplementary service enables a served user to have the network redirect to another user calls which are addressed to the served user's ISDN number and meet busy. The CFB supplementary service may operate on all calls@ or just those associated with specified basic services. The served user's ability to originate calls is unaffected by the CFB supplementary service. The CFNR supplementary service enables a served user to have the network redirect to another user calls which are addressed to the served user's ISDN number@ and for which the connection is not established within a defined period of time. The CFNR supplementary service may operate on all calls@ or just those associated with specified basic services. The served user's ability to originate calls is unaffected by the CFNR supplementary service. The SCF supplementary service enables a served user to specify the forwarding of their incoming calls to a selected destination subject to certain conditions or circumstances e.g. the calling line identity of the calling user. The user is also allowed to interrogate the screening list. The CD supplementary service enables the served user to respond to an incoming call by requesting redirection of that call to another user. The CD supplementary service can only be invoked before the connection is established by the served user@ i.e. in response to the offered call@ or during the period that the served user is being informed of the call. The served user's ability to originate calls is unaffected by the CD supplementary service. The present document also describes interactions for Service enhancements based on DDI ranges for Diversion services detailed in ES 201 481.The diversion supplementary services are applicable to all circuit-switched telecommunication services. Further parts of EN 300 207 specify the method of testing required to identify conformance to the present document. The present document is applicable to equipment supporting at least one of the diversion supplementary services@ to be attached at either side of a T reference point or coincident S and T reference point when used as an access to the public ISDN.