A little on the Radio ID

On a DMR system, each radio must have a unique Radio ID. Duplicate Radio IDs may result in unexpected operation (such as a user moving at the speed of light between two locations on the map). The factory default is 1.

The DMR Radio ID is used to construct the CAI address of the radio - which is effectively the IP address of the radio used for data and voice.


For conventional (i.e. single site and IPSC) systems, the range is from 1 to 16776415. For Capacity Plus (single and multi-site) systems it is from 1 to 65535.

In digital mode the radio will include its own Radio ID on all transmissions (i.e. source address). This is also used to selectively call (private/one-to-one call) or send data to a single radio. The users Alias (which comes from the contact list) will be shown on the screen while they are transmitting - and unlike Select-5 and MDC1200, no tones or data is heard since the messaging is embedded in the packet header.

The Radio ID is a decimal number, so for interest sake, to work out the IP address of the radio, you need to convert the Radio ID into an IP address and change the first octet with the CAI Network value listed in the codeplug - by default this is 12.

NB! Changing the CAI Network value can have undesired results so leave the above two values alone (Finger weg as we say here in Germany).

As an example, if the Radio ID is 2017, it's IP address for voice will be 12.0.7.225 and for data, the address will be 13.0.7.225. By the way, the CAI Group Network defines the first octet of the Talkgroup IP address so when you make a group call to Talkgroup 1, your MOTOTRBO radio is sending voice packets to 225.0.0.1.