How about if it was a toggle with On (intercom) in the center position, Off at the bottom and then the aircraft system would be press up and hold to talk? A two switch system isn't out of the question but every switch or connector introduced is a potential point of failure so I'm trying to simplify as much as possible. Most applications we are in right now don't require an OFF position so you're talking betwen headsets by default and if you want to talk outside your group then you have a (momentary) PTT switch.
At this point in the game I'm far less concerned about guessing who may or may not buy because if we can't define and meet the user requirements then no one will buy it. At the end of the day, if no MajCom is willing to fund it I want them to have to say 'Yeah, we could use this but we don't want to' rather than 'Well, we would buy it except for "X" function isn't there.'
350 feet shouldn't be an issue at all, but.... until I can get inside and around a couple of birds to test it...:confused:.... Maybe at Rodeo someone will invite me out to play.