So it won't send the advanced list messages to the GTR200... will it send the older, standard messages like what the Garmin 496 will? I'm talking about "NMEA + VHF" mode. There are a couple of sentences, very simple to implement. $PMRRC00 sets the active frequency, $PMRRC01 sets the standby... it's not difficult at all, it's right there in the Garmin (Apollo) install document for the SL40. Pretty sure that still works with the GTR 200. Even without the fancy text display, it would be nice to be able to at least set the standby frequency with a screen tap.
Or does it already?