scope:

This European Telecommunication Standard (ETS) defines the TErrestrial Trunked RAdio (TETRA) Direct Mode Operation (DMO). It specifies the basic air interface, the inter-working between Direct Mode (DM) groups via repeaters, and inter-working with the TETRA Voice plus Data (V+D) system via gateways. It also specifies the security aspects in TETRA DMO, and the intrinsic services that are supported in addition to the basic bearer services and teleservices.

This part applies to the general network design of TETRA DMO as follows:

- it defines and specifies the circuit mode reference points for the Mobile Station (MS), repeater and gateway to the Switching and Management Infrastructure (SwMI);

- it defines and specifies models of the air interface protocol stack where the different functions of layers and sub-layers are listed;

- it defines and specifies the TETRA DMO addressing and identities and their organization in groups corresponding to the different functions;

- it defines and specifies the functions provided by the circuit mode teleservices used for speech and basic services used for data transfer;

- it defines and specifies the intrinsic services that extend the capabilities of the circuit mode bearer services and teleservices;

- it defines and specifies the functions related to the transport of short data messages.

NOTE: This part of this ETS may, by its nature as a general design statement, require updating as later specific parts of the ETS are completed in order to avoid any non-alignment. If a discrepancy occurs between this part and any other part of this ETS, then the other part will take precedence. This part will be updated at a frequency consistent with maintaining the integrity of this ETS as a whole.