a bit strange, as Dr. Bill says they (PTT In Mic IN) should be isolated.
When I had PTT In tied to Mic In going to TRS jack PTT did not work.
After remembering Ver 10 and Dr. Bill,s hint I ran Mic and Mic Ground in a 2 conductor shielded cable Shield to Ground at front panel open on other end.
Mic in and Mic Ground? were inside shield and attached directly to 2 pin header on Audio Shied.
PTT In, Ground and Key A and B are now on 8 pin IDC going to ACC Jack on back of Main board.?
I use a foot switch on PTT In, all rigs are setup this way old habit.?
Tim W4YN
