The present document defines the stage 1 specifications of the Supplementary Service Pre-emptive Priority
Call (SS-PPC) for the Terrestrial Trunked Radio system (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.
The present document specifies the service description of the supplementary service and the procedures to be expected
with successful and unsuccessful outcomes. In addition the present document specifies the interactions with other
TETRA supplementary services and interworking considerations.
Charging principles are outside the scope of the present document.
The SS-PPC enables a user to have preferential access to SwMI resources including pre-emption of calls.