CHCOMM

Hi all, this is my first post, I apologize for making it a question.

Does anyone still use CHCOMM3? I've been able to interface FSX to a microcontroller to control just about everything in the simulator with the exception of the NAV and COM radios. For the life of me I can't figure out the proper string to send to CHCOMM to make these work.

Is anyone able to assist? All I need to see is what CHCOMM is expecting to see from my device - the ASCII string it's looking for.

Any help would be appreciated.