The present document 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 Direct Mode Repeater (DM-REP) air interface and contains the specifications, where
applicable, of the physical, data link and network layers according to the ISO model.
The specifications contained herein apply to a DM-REP as a stand-alone unit supporting two calls on the air interface
(type 2 DM-REP). They also cover the operation of a DirectMode Mobile Station (DM-MS) with a type 2 DM-REP.
NOTE 1: The specifications for a Direct Mode Repeater/Gateway (DM-REP/GATE) combined implementation are
provided in ETS 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 a single call on the air interface (type 1
DM-REP) are provided in EN 300 396-4 [4].
The protocol for a DM-MS operating with a type 2 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 ETS 300 396-2 [2]
and ETS 300 396-3 [3] for direct MS-MS operation, and EN 300 396-4 [4] for type 1 DM-REP operation. These clauses
define where the protocol in parts 2, 3 and 4 applies without change, or where it applies with the specified amendments,
replacements or additions. Where no reference to parts 2, 3 or 4 exists, the subclause 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 th (...abbreviated)