Capt. Mikey

I've recently installed a new Garmin GPS model 545S and connected port 1 via NMEA0183-HS to VHF/AIS and port 2 via std. 0183 to VHF radio (DSC) & ComNav 1001 autopilot. The interfaces work fine w/ exception of that to the autopilot. While I know that the port 2 is outputting correct lat/lon position data to the VHF radio, APB data from the GPS is not being recognized by the autopilot. ComNav was not very helpful, simply stating that the 1001 was looking for RS422 signal levels while the Garmin outputs RS232 signal levels. However, both advertise 0183 compatibility (in most cases a RS422 receiver will accept RS232 signals). Has anyone had experience interfacing a Garmin GPS w/ a ComNav AP?

Rubberhead

There might be a software setting on the Autopilot. I know the Garmin can set each port to a different protocol, maybe even a different electrical standard.