Thanks SDQDI,
I'll give it a try.
Here is the instructions out of the manual
"ComPriority is turned on or o by the bottom-most controller button. With ComPriority on and when radio communications are detected, the volume
of auxiliary devices will be signi cantly reduced. To enable ComPriority, turn on the feature, plug into your intercom and talk into the headset microphone while playing music over a wired device. If enabled, your auxiliary music will decrease when you start to talk. During cell phone calls, the other party will be muted, so disable ComPriority before making calls. "