If I use Mimer SoftRadio for a phone call and I in the middle of the conversation needs to transmit on the radio, what happens.

As in the example above, you will still monitor the radios though you are in a phone call. When you press PTT on a radio your microphone will be switched over to the radio and temporally leave the phone call. When you release the PTT your microphone is back in the phone call. During your radio PTT you will still monitor the phone call.

In later SoftRadio, from 2020, you can set an automatic decrease of the audio volume from the radios when a phone call is ongoing.