Direct Mode Operation (DMO) 2-21
March 2009 Chapter 2 - MTP850 Ex/MTP810 Ex Product Information Manual 6866588D21-D
is provisioned in the terminal, upon pressing the Emergency key/button in DMO, the terminal will go
into Emergency Mode and allow the user to initiate an emergency call.
6.4.1 DMO Emergency Alarm
If the terminal is provisioned with the emergency alarm feature, upon entry into emergency mode,
the terminal sends an emergency alarm. This alarm is sent by sending a specially designated SDS
status message to the address of the selected group. The alarm status is received by all the radios
attached to the same talkgroup.
6.5 DMO Inter-MNI Calls
The terminal supports receipt of DMO group calls addressed to the "Open MNI" (MNI and SSI all
’1’s), and those addressed to the "Open Group" (SSI is all ’1’s) with the home MNI or the MNI of the
currently selected group.
The terminal has a list of partnership DMO networks. If a call is received to the SSI of the selected
group and an MNI that is in the partnership list, the terminal will join the call if the selected group is
provisioned to enable partnership.
The terminal supports initiation of a DMO group call to any provisioned GTSI. The MNI does not
have to be in the partnership list.
6.6 DMO Gateway/Repeater
The terminal provides the capability of communicating in DMO mode with a TMO group via the IOP
certified gateways as defined in [Ref 23].
A DMO repeater re-transmits information received from one DM-MS to other DM-MS(s) over the
DMO air interface.
The terminal allows the user to operate for each DMO talkgroup in one of 3 modes. The user can
choose which mode to operate in:
• DM-MS to DM-MS only: In this mode, the terminal will only initiate calls on this talkgroup
directly - not via a gateway or repeater.
• Specific gateway: In this mode, the terminal can initiate calls on this group directly DM-MS to
DM-MS or via a specific gateway address that is specified for this specific talkgroup. This
gateway address will be editable by the user.
• Auto gateway: In this mode, the terminal can initiate calls on the selected group directly with
another terminal or via any usable gateway that is detected as present.
• Repeater: In this mode, the talkgroup should link to a repeater and by that to enhanced it’s
coverage area.
• Specific gateway and repeater: In this mode, the terminal will use only the gateway with the
specified gateway address for that talkgroup and/or a DMO repeater.
• Automatic gateway and repeater: In this mode, the terminal will use the first available
gateway for that talkgroup and/or a DMO repeater.
If either ’Specific gateway’ or ’auto gateway’ mode is chosen, and a suitable gateway is found, all
outgoing calls will be made via the gateway. If a suitable gateway is not found, or a call setup via the
gateway fails, the terminal will attempt to set up the call directly DM-MS to DM-MS.
If the terminal is idle (not involved in a call), it will follow incoming calls from either MS-MS or from a
suitable gateway no matter which gateway mode is chosen.
When the user is operating on a gateway and/or repeater, the terminal will indicate this to the user.
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