This sort of relates to my 750 completion.  I purchased an Icom A210 at OSH for two reasons - there was a special discount on the price and it has a built in intercom.  I have an intercom in my C-120 (not in the radio but separate unit) that is VOX(voice operated).  I was hoping to have that same function with the Icom but the wiring schenatic indicates a separate PTT switch for the intercom function.  I thought I could jumper the pins to make the intercom hot all the time but a local avionics tech told me that then the PTT radio transmit function wouldn't work.  I know there are several 650/750 builder owners out there with the Icom A210 and looking for a second opinion or how you have your's wired?

Norm Neuls

Wasilla, AK   

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I have an ICOM A210 installed in my CH750. I have two push to talk buttons (one on each side of the "Y" stick). The built in intercom works great. No issues. Reading the manual is the key to success.

I had an avionics tech build the wiring harness for my A210. He said the intercom function can be switched off or on by a cutout switch.  This had nothing to do with the PTT.  I installed both switches myself (PTT and cutout) to the wires he provided for each function and both work well.  The cut out switch disables the intercom function when I'm flying alone.  Even with the squelch function is turned way up, sometimes air rushing in from my window vent activates the VOX.  The seperate switch allows me to enjoy a quiet cabin.  The PTT switch only activates the transmit function of the A210. Hope this helps.

Thanks, Bob & Don.  Don, from your reply it appears the cut out switch takes the place of the PTT intercom switch(as opposed to the PTT transmit switch) as shown on the wiring diagram.  I can see the rationale of that if there is noisy background noise.  So what I draw from this, is that with the intercom cut out switch in the ON position, VOX communication can be carried on between pilot and pax and vice versa.  Am I correct? 

That's correct.

I'm late joining this discussion but I have a question for those using the built-in intercom in the A210.  How would you compare it to stand-alone intercoms?  I've had Sigtronics and Flightcom in my other aircraft and both would occasionally pick up aircraft noise.




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