Wow! I've never seen a mil-spec AirComm 300 audio mixer panel in a Cessna 150 before. Those things aren't cheap, but it's a bit of an overkill.
Until 1996, 46S was used by the Baltimore County Police to give me a speeding ticket every time i drove through MD. They used the mixer to tie into all other aircraft and land vehicles to get me if I tried to outrun them. The headsets are helicopter type so they could interchange to , I guess helicopters.
That's what confused me a bit, because everything seems solid w/ the plane except the alternating OH's.(which is a biggy to me) I'll double check Sunday.
Thanks for all the great feedback.
Jerry