I just acquired an IC-2410H, and noticed that if I plug microphone into radio it will key up on it's own. I have checked the functionality of the PTT switch, it is fine. The microphone is an IC-HM 56A, and has a microprocessor in it. I have reset the radio, and mic, still keys up all the time. If anyone on the list has any ideas of what the problem is, I would be very grateful. Mark M. Smith, W4MMS