nRoute only understands Garmin protocol, not NMEA protocol.
If you want to use a GPS receiver that gives NMEA protocol with nRoute you must use a program named
GPSGate Express. This will read the NMEA protocol from the GPS receiver and translate it to Garmin protocol to send to nRoute.
GPSGate is shareware but it has a 14 day free trial so you can try it to see if it is what you need.
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