I don't have a touch screen unit.

I still confused about what is needed to upgrade to the SV-ADAHRS-200/201. It would seem that the
only way to free up a serial port is to add the SVN network interface, right? Do I need to upgrade the
screen do use that?

I also am not clued in to the SV-ADSB-472 (74113) to SV-ADSB-470 (74112)
trade in program. Costs and benefits?

Thanks,
-Dan