scope:

This European Telecommunication Standard (ETS) defines the TErrestrial Trunked RAdio system (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 and teleservices.

This part applies to the TETRA DMO Mobile Station - Mobile Station (MS - MS) air interface and contains the specifications of the physical layer according to the OSI seven layer reference model.

It establishes the TETRA DM radio aspects (layer 1 and lower MAC):

- it defines and specifies the modulation;

- it defines and specifies the radio transmission and reception;

- it defines and specifies the synchronization;

- it defines and specifies the channel coding;

- it defines and specifies the channel multiplexing;

- it defines and specifies the control over the radio link.