scope:

This ETS defines the Terrestrial Trunked Radio (TETRA) Direct Mode Operation (DMO). It specifies the basic air interface, the interworking between Direct Mode (DM) groups via repeaters, and interworking 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 Direct Mode gateway air interface and contains the specifications, where applicable, of the physical, data link and network layers according to the International Organization for Standardization (ISO) model.

The specifications contained herein apply to a gateway, both as a standalone unit (DM-GATE) and also to a Direct Mode Repeater/Gateway (DM-REP/GATE) combined implementation. In the case of a combined implementation the repeater part of the gateway may be either a type 1A repeater, operating on a single RF carrier, or a type 1B repeater, operating on a pair of duplex-spaced RF carriers.

The specification also covers the operation of a Direct Mode Mobile Station (DM-MS) with the gateway.

The protocol for a DM-MS operating through a gateway is specified in clauses 5 through 8, 14 and 15. Much of this protocol is defined in the form of a "delta document" relative to the specification provided in ETS 300 396-2 [2] and ETS 300 396-3 [3]. These clauses define where the protocol in parts 2 and 3 applies without change, or where it applies with the specified amendments, replacements or additions. Where no reference to parts 2 or 3 exists, the subclause should be regarded as independent.

The protocol for the gateway is specified in clauses 9 to 13, 16 and 17.

The normative annexes mainly specify the parameter values used in the protocol.