The present document defines the stage 2 specifications of the Supplementary Service Priority Call (SS-PC) for the Terrestrial Trunked RAdio (TETRA). TheSS-PCisdefined to enableausertohavepreferentialaccessto thenetwork resourcesinaTETRAsystemin times of congestion. The SS-PC applies for the basic services: circuit mode calls (speech or data). The SS-PC specifies the definition, activation, deactivation and interrogation for the usage of low and high call priorities in the TETRA system. The SS-PC operations are defined for Switching and Management Infrastructure (SwMI), for the Mobile Station (MS) and for the Line Station (LS). SS-PC is defined for subscrib