Plus is the key word
Yes, the ST 4000 plus will communicate with a Garmin and display xte, and other gps data without any interfacing unit.I think the "plus" is the key word, earlier ST 4000 units needed the interface.In fact, the XTE screen is my favorite to leave selected on the autopilot. The base gps is used for heading, track and other information but on my paricular Garmin, the 125 / Sounder xte is only available on a couple of screens that I don't care much about... hence the reason for displaying it on the auto pilot control head.Neither the control head or full feature remote will pick up the depth from the Garmin gps/sounder combo but it will do track feature from gps data just fine.There were a couple of times shortly after interfacing for track navigation that I questioned if the pilot was working properly... but it finally sank into my thick skull that my boat has a lot of leeway in a strong wind and the track feature was choosing a course with a significant heading difference to keep the boat on the rhumb line.