Hi David

Sorry, there are no DTMF commands unless you are a control operator for one of the links.. The controllers on the system are very basis anyhow..

There is IRPL and Echolink on the system for incoming calls only and out going for special events. Earthquakes, State
Wide RACES/ARES ect.
That is what you are most likely hearing.

Thanks for the interest in the system

Mike 73