I have 2 GM-30 Plus radios that are doing this, and it's frustrating. I hear a call from our repeater, no problem. When someone answers, the green activity light will illuminate, but no audio. If I press P2 twice to cycle from channel A to B, and back to A I can hear the reply. You have to do the same thing to hear the reply again. This happens on all 3 of our repeaters. The DPL codes are all correct. My mobile radios and DB-30 (non Plus) all hear everything just fine, it's just the DB-30 Plus radios acting like this.