Airtronics to Futaba Buddy Cord
As I understand it, the data passed through the buddy cord is the data normally sent to the RF deck (transmision circuit). Therefore, as long as both systems use the same frequency shift, a buddy cord can be made to work.
In other words, if I understand it correctly, Futaba (-ve shift) and Airtronics (+ve shift) are not compatible via the buddy cord, even if you make the plugs fit.
I could be wrong though, so if anyone has a correction to add, fire away...