SSH ETS 300 392-11-24:2000 ed.1

Terrestrial Trunked Radio (TETRA); Voice plus Data (V+D); Part 11: Supplementary services stage 2; Sub-part 24: Call Retention (CRT)

Scope

This ETS specifies the supplementary service Call Retention which is applicable to various basic services supported by TETRA SwMIs. Basic services are specified in ETS 300 392-2 [4]. SS-CRT is a supplementary service which applies either during call establishment or once call is established to protect a call from pre-emption by another call of lower priority. Supplementary service specifications are produced in three stages, according to the method described in ITU-T Recommendation I.210 [2]. The present document contains the stage 2 specifications of SS-CRT. The stage 2 descriptions specify the supplementary services functional entities, their relations and the information flows needed to support the supplementary service.