From the AF-Pilot Installation Manual (Page 9):

"The AFS Pilot can follow a programmed flight plan from a GPS, independent of the EFIS system, by pushing the EFIS button. The screen will display EXT LS to indicate that it is following an external
lateral steering signal."

Does this mean the Autopilot gets the Signal from the RS 232 or does this mean the Autopilot gets the Signal from the GPS via the Arincline? (Does this work only with Garmin GNS or does this also work with a Handheld GPS)

Thanks
Markus