[Elecraft] KX3 mic wiring info

[Wayne Burdick]

Mike,

Here's how the mic is wired:

   Sleeve = shield ground
   ring2 = logic ground
   ring1 = PTT/UP/DN
   tip = mic audio

Since a 3-circuit plug merges sleeve and ring2, a mic with such a plug  
could be wired to work with the KX3 and provide PTT, though I don't  
have one with which to test this idea.

On the ring1 line, resistance to ground determines the function:

   PTT:  0 ohms
   DN:   4.7 k
   UP:   10 k

We may invoke another function with the combination of UP+DN (3.2 k).  
We could call this a "meta" operation that changes what UP/DN do. For  
example, their function could switch to band, RIT, or volume up/down.

Let me know if your target mic will work with the above wiring as-is,  
or if a simple mod is required, and we'll add it to our KX3 FAQ.

73,
Wayne
N6KR