scope:

The present document defines the stage 2 specifications of the Supplementary Service Late Entry (SS-LE) for the Trans-European Trunked Radio (TETRA). The SS-LE allows radio users to be informed of and, if they are concerned, to join an already existing point-to-multipoint speech or data call. Man-Machine Interface (MMI) and charging principles are outside the scope of the present document. Stage 2 describes the functional capabilities of the supplementary service introduced in stage 1 description. Stage 2 identifies the functional capabilities for the management of the service in the Switching and Management Infrastructure (SwMI), in the Mobile Station (MS) and in the Line Station (LS). Stage 2 also describes the information flows between these entities and also the flows sent over the Inter-System Interface (ISI).