I think I have really messed up. I sent my 3400 in a few month's ago for a new screen. When it was returned, my autopilot (TrueFlight) would not follow the EFIS heading bug of the altitude bug.

I started changing serial port assignments in the configuration screens and am now probably ruined. Going upside down under the panel and pulling all the wiring would be terrible. I did not build the aircraft.

Starting at step 1, is there a way I can determine what device is connected to each port - probably by choosing one and flying.

I have a Garmin 480 with traffic / an SL30 / a remote AIRINC.

My software is 7.4