IC-A200 to FC 403MC interface

I am hooking up the icom A200 radio to the flitecom 403mc intercom,
both standard issue and provided by Vans. Am having trouble with
transmitting. Anybody have a clue as to which two pin numbers off the
A200 comm radio are considerd "Transmit Keyline" and "Transmit Audio"
that hook up to pins #8 and #17 respectivly ,on the intercom
harness?? I am recieving fine so I think I have the headphone right


Thanks
doug
90625

Here's a quick and dirty rundown ICOM to 403MC.

ICOM - 403MC
H (Phone Out) - 21 (A/C Phone)
J (Comm Mic Audio) - 16/17 (Transmit Audio)
9 (PTT) - 8 (Comm Radio Key Line)

Of course there should be the audio "Lo" or grounds and shields hooked up with this. That's the only drawback to the Flightcomm stuff...they don't use many audio grounds so wiring can be less than intuitive.

Hope this helps. I tell you, after doing literally dozens upon dozens of various radio/intercom harnesses, I wish like heck that there could be some minimal standardization of terminology between radio and intercom mfgrs. Seems like everyone in every country likes to do things differently. Garmin & PSE have gotten the closest as I see it, but throw a Becker, Collins, Terra, ARC, Icom, Narco, King, VAL, Comtronics, Sigtronics, Softcomm, NAT and a few others into the mix and it's like learning a new foreign language all over again for the variety of combinations!

Cheers,
Stein.

Stein.

Thanks, Thats the way I interpeted the wire diagrams and info provided from Icom, Flitcom and Van's and the way I wired it up. Must be something deeper.....bummer. Will keep digging and testing but at least I know the connections from the radio are right and it gives me a place to start from.

Thanks again
doug
90625

Much time later. Checked continuity on every pin and wire on the wiring harnes, that came from Van's, and it's destination. Also checked van's wire labels to make sure they hadn't mislabed or something, it all checked out perfect. Removed the intercom and took it over to a friend whom has an RV-7 (finished and flying) with the same unit in his and we switched them to see if it would work in his plane. NOT! Looks like a bad unit fresh out of the box. Anybody else experiencing bad brand new parts? I also had a bad ammeter straight out of the box. Not bad I guess over the scope of the whole project, but it can sure can get frustrating sometimes. Don't these manufactures test their products before they send them out.(Not complaiining about Van's mind you). The prices they get for all these aviation products seems they could afford a little quality control..... Soap box is put away....

doug

Pull the ICOM and check pin 9

PTT is just grounding of pin 9 (icom). Pull the icom radio out the rack, put a probe on pin 9, push the PTT and see if you get a ground on pin 9. You can work thru the tray with a long probe if you have one. It is the 9th pin from the left bottom row looking thru the tray at the back connector. It can be anything from the PTT swtich itself to pin 9 and everything in between.

If no ground you wired it incorrectly, which is way more likely at this point than a problem with the radio or intercom, in my opinion. You may need power to the intercom unless it is fail safe, i.e., works without power for at least basic pilot ATC com. G