Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Specification, functional model and information flows - Call diversion supplementary services
The international community has decided to make this standard available only in
the English language version. It has been adopted as a National Standard of
Canada on this basis. This National Standard of Canada is equivalent to International Standard
ISO/IEC 13872:1995. 1 Scope This International Standard specifies the supplementary services Call
Forwarding Unconditional (CFU), Call Forwarding Busy (CFB), Call Forwarding No
Reply (CFNR) and Call Deflection (CD), which are applicable to various basic
services supported by Private Integrated Services Networks (PISN). Basic
services are specified in ISO/IEC 11574. SS-CFU, SS-CFB and SS-CFNR are supplementary services which apply during call
establishment providing a diversion of an incoming call to an other
destination. SS-CD is a supplementary service which allows a served user to
respond to an incoming call by requesting redirection of that call to another
number specified in the response. Supplementary service specifications are produced in three stages, according to
the method described in CCITT Rec. I.130. This International Standard contains
the stage 1 and stage 2 specifications of the Call Diversion supplementary
services. The stage 1 specifications (clauses 6, 7, 8 and 9) specify the
supplementary services as seen by users of PISNs. The stage 2 specification
(clause 10) identifies the functional entities involved in the supplementary
services and the information flows between them.