> 1.  Can you satisfactorily switch between audio inputs,
any audio panel can do this..
 
> 2.  What do you do about a marker beacon receiver?
skip it... the days of getting an extra 50feet on the ILS
are over and GPS distance is better.  heck, who wants
another antenna slowing you down any ways?
 
> 3.  Do the voice switched intercoms work satisfactorily?  
personally I like the simple, mono, auto squelch
http://www.ps-engineering.com/pma4000.shtml
 
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