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-tomultipoint
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).
NOTE: The stage 2 description is followed by the stage 3 description, which specifies the encoding rules for the
information flows and process behaviour for the different entities in SwMI, MS and LS of the service.