User's Guide

Operating Modes
Your radio supports the following operating modes:
In Trunked Mode Operation (TMO Mode) your radio operates on the network infrastructure
supplied by your service provider.
In Direct Mode Operation (DMO Mode) your radio can transmit directly to another radio
(antenna to antenna). In DMO mode radio coverage depends on the position of the caller and
the receiving radio. When you switch to DMO your radio leaves the network and tunes to the
selected DMO talkgroup. See also DMO Mode below.
In Repeater mode your radio enables two or more radios operating in DMO mode to
communicate over an extended range, automatically relaying voice and messages by
operating as a repeater. See also Repeater Mode on page81.
To change operating mode from the Home screen
Press the Menu context key, then select Networks > Operating Mode. Scroll to the mode
(highlight it) and press Select.
Alternatively, a soft key may be programmed as a shortcut to this function or a shortcut may be
added to the Shortcut Bar. Open the Shortcut Bar (in the Home screen press the Shortcut context
key), scroll to the Operating Modes shortcut and then press the Select context key. You can then
select the operating mode.
DMO Mode
In Direct Mode Operation (DMO), radios communicate directly with other TETRA radios without
using a network. The radios must all switch to DMO and select the same talkgroup, and that
talkgroup must use the same channel (frequency). Communications to other users on the network
are impossible unless they also switch to DMO and select the same talkgroup.
This means that in DMO, communications to the dispatcher is impossible unless they also switch to
DMO and select the same talkgroup, or if they communicate through a DMO gateway (see DMO
gateway operation).
Group calls
DMO supports group calls (see Group calls on page58) which are made and received in the same
way as radios operating in TMO. In DMO TETRA Alarm Calls are either sent to the currently
selected DMO talkgroup or (if customised) may switch to TMO to make the call. If TMO is unavailable
Alarm Calls are made using DMO. See Emergency operation on page25.
Individual calls
Your radio can be customised to allow you to make individual calls to other radios working in DMO
which are attached to the same talkgroup. In this case individual calls are initiated by pressing the
PTT key.
User Guide 79