scope:

The present document defines the stage 1 description of the call hold supplementary service (SS-HOLD) for the Terrestrial Trunked RAdio (TETRA) as provided by European operators. The stage 1 description is an overall service description from the user point of view but does not deal with the details of the human interface itself (see ITU-T Recommendation I.130 [1]). SS-HOLD enables a user to interrupt communication on an existing individual call and then subsequently, if desired, re-establish communication. 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.