Information technology - Telecommunications and information exchange between systems - Private Integrated Services Network - Specification, functional model and information flows - Call transfer supplementary service
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 13865:1995. 1 Scope This International Standard specifies Supplementary Service Call Transfer
(SS-CT), which is applicable to various basic services supported by Private
Integrated Services Networks (PISNs). Basic services are specified in ISO/IEc
11574. SS-CT is a supplementary service which enables a user to transform two of that
user's calls (of which one must be answered) into a new call between the other
two users of the two calls. Supplementary service specifications are produced in three stages, according to
the method described in CCITT Recommendation I.130. This International
Standard contains the stage 1 and stage 2 specifications of SS-CT. The stage 1
specification (clause 6) specifies the supplementary service as seen by users
of PISNs. The stage 2 specification (clause 7 and 8) identifies the functional
entities involved in the supplementary service and the information flows
between them. The International Standard contains two stage 2 specifications reflecting
different ways of operating the service within the network: transfer by join
and transfer by rerouteing.