This International Standard specifies the signalling protocol for the support of the Route Restriction Class (RRC) additional network feature (ANF-RRC) at the Q reference point between Private Integrated Services Network Exchanges (PINXs) connected together within a Private Integrated Services Network (PISN).

ANF-RRC is a feature which applies in the establishment phase of a call, allowing that call to access facilities that are within an allowable restriction range.

The Q reference point is defined in ISO/IEC 11579-1.

Service specifications are produced in three stages and according to the method specified in CCITT Recommendation I.130. This International Standard contains the stage 3 specification for the Q reference point and satisfies the requirements identified by the stage 1 and stage 2 specifications in ISO/IEC 13242.

The signalling protocol for ANF-RRC operates on top of the signalling protocol for basic circuit switched call control, as specified in ISO/IEC 11572, and uses certain aspects of the generic procedures for the control of supplementary services specified in ISO/IEC 11582.

This International Standard also specifies additional signalling protocol requirements for the support of interactions at the Q reference point between ANF-RRC and other supplementary services and ANFs.

This International Standard is applicable to PINXs which can interconnect to form a PISN.