scope:

This European Standard (Telecommunications series) has been produced by ETSI Technical Committee Communication, Networks and Systems Interconnection (ECMA), and is now submitted for the ETSI Standards One-step Approval Procedure. The present document is one of a series of standards defining services and signalling protocols applicable to Private Integrated Services Networks (PISN). The series uses the Integrated Services Digital Network (ISDN) concepts as developed by ITU-T and conforms to the framework of standards for Open Systems Interconnection (OSI) as defined by ISO/IEC. This particular EN specifies the Call Priority Interruption and Call Priority Interruption Protection Supplementary Services.