Abstract ISO/IEC 11582:2002 defines the signalling protocol for the control of Supplementary Services and Additional Network Features (ANFs) at the Q reference point. The protocol is part of Private Signalling System no. 1 (PSS1), known informally as QSIG. The Q reference point exists between Private Integrated services Network eXchanges (PINXs) connected together within a Private Integrated Services Network (PISN) and is defined in ISO/IEC 11579-1. Detailed procedures applicable to individual supplementary services and ANFs are beyond the scope of ISO/IEC 11582:2002 and will be specified by other standards for those services which are standardised and by individual manufacturers for proprietary services using the capabilities defined in ISO/IEC 11582:2002. ISO/IEC 11572 defines the Layer 3 protocol for circuit-switched call control at the Q reference point. ISO/IEC 11582:2002 defines additional protocol procedures, to be used in conjunction with those defined in ISO/IEC 11572 for the control of supplementary services and ANFs. NOTE 1 Typical examples of the application of these generic functional procedures to some supplementary services are provided in annex C, for explanatory and illustrative purposes only. NOTE 2 Specific supplementary services and Additional Network Features may require additional information transfer mechanisms which are service or feature specific and are beyond the scope of ISO/IEC 11582:2002.