The multi-part deliverable ETS/EN 300 396 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.
The present document defines TETRA Managed Direct Mode Operation (M-DMO).
M-DMO provides a means to restrict the use of Direct Mode Operation (DMO) by requiring prior authorization before a
Direct Mode Mobile Station (DM-MS) is permitted to transmit on a radio frequency. This modifies the operation of
DM-MSs from that specified in ETS 300 396-3 [3], EN 300 396-4 [4], ETS 300 396-5 [5] and EN 300 396-7 [7].
M-DMO provides a control mechanism by which radio frequencies (M-DMO frequencies) may be given for DMO use
for a period of time; those frequencies are considered to be managed frequencies. All M-DMO devices operating on a
managed frequency shall comply with the transmit restrictions defined in the present document.
An M-DMO DM-MS (M-DM-MS) may receive the authorization to transmit from a broadcast signal sent on the
M-DMO frequency. Or, alternatively, it may obtain the authorization directly on the V+D side from the SwMI or from
an M-DMO management station.