[GPSNavX]

rirvine, yes your configuration makes sense. You have effectively created two GPS input into MacENC. That works fine because each panel only looks at the NMEA data it cares about, but as you note when combining the NMEA data back onto a TCP/IP port the filter "Only Processed" needs to apply.

On the otherhand there is no need for a "Only Processed" option for the GPS Repeat serial port as instruments nor AIS NMEA data is repeated to the serial port.

I believe MacENC offers many options for interfacing NMEA instrumentation. Compare with other OS X GPS applications that only support ONE serial port.