scope:

This European Telecommunication Standard (ETS) defines the stage 1 specifications of the Supplementary Service Access Priority (SS-AP) for the Terrestrial Trunked Radio (TETRA). Stage 1 is an overall service description from the users point of view but does not deal with the details of the human interface itself. This ETS specifies the service description of the supplementary service and the procedures to be expected with successful and unsuccessful outcomes. In addition this ETS specifies the interactions with other TETRA supplementary services and interworking considerations. Charging principles are outside the scope of this ETS. The SS-AP enables to define specific priorities in an MS for uplink random access messages (at the air interface) for circuit mode or packet mode communications.