Have a SV1000 system with SV-XPNDR-261, GPS-250, ARINC-429, Avidyne IFD540 GPS NAV/COM and a Garmin GTR200 Comm. I am having a problem with the -261 seeing the RS232 IN on pin 3 from the IDF540 in either the aviation format or the ADS-B format. The GPS-250 input selection works fine and I see...