Dimetra: Critical Site Assignment and Requested Sites Assignment

Critical Site Assignment is a feature in Dimetra that supplements group call in that it is possible to create a list of Critical Sites for each talkgroup.

A Critical Site is a RF site that must be included in a group call for it to be set up. In the Dimetra Express Network Manager, each talkgroup has 'Critical Sites' list associated with it.
So, even when Fast Start is being used, the call will not be set up until traffic channels (timeslots) are available at all the critical sites for this talkgroup.

With Requested Sites Assignment,  when a group call is set up, it will be set up at each requested site, even if there are no members of the talkgroup registered at those sites. In this way, requested sites are always relaying traffic from the associated talkgroup.
This feature can be used to ensure that radios (MS) that have Transmit Inhibit (TXI) enabled, or are scanning, can receive talkgroup calls even though the Location Register shows that there are no  affiliated talkgroup members at that site.

It is possible to specify a list of requested sites for each talkgroup in the Network Manager of a Dimetra Express system.

Both of these features are available in Dimetra Express as of R1.4.

The Location Register is a service that exists within the Zone Controller of a Dimetra (Motorola TETRA) system. It contains information about the affiliation status of all active radios on the TETRA system - so things like, which site is the radio on; which talkgroup is it listening to etc.