The multi-part deliverable EN 300 396 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 and teleservices.
This part applies to the TETRA DMO Repeater (DM-REP) air interface and contains the specifications of the physical,
Data Link Layer (DLL) and the network layer according to the ISO model.
The specifications contained herein apply to a DM-REP as a stand-alone unit supporting a single call on the air interface
(type 1 DM-REP). They also cover the operation of a Direct Mode Mobile Station (DM-MS) with a type 1 DM-REP.
NOTE 1: The specifications for a Direct Mode Repeater/Gateway (DM-REP/GATE) combined implementation are
provided in EN 300 396-5 [5], together with the specifications for a Direct Mode Gateway (DM-GATE).
NOTE 2: The specifications for a DM-REP as a stand-alone unit supporting two calls on the air interface (type 2
DM-REP) are provided in EN 300 396-7 [7].
The protocol for a DM-MS operating with a type 1 DM-REP is specified in clauses 5 through 8, 10 and 11. Much of
this protocol is defined in the form of a "delta document" relative to the specifications provided in EN 300 396-2 [2]
and EN 300 396-3 [3] for direct MS-MS operation. These clauses define where the protocol in EN 300 396-2 [2] and
EN 300 396-3 [3] applies without change, or where it applies with the specified amendments, replacements or additions.
Where no reference to EN 300 396-2 [2] or EN 300 396-3 [3] exists, the clause should be regarded as independent.
The protocol for the DM-REP is specified in clauses 9 and 12.
The normative annex mainly specifies the parameter values used in the protocol.