Had to look up what a TR1 is… an AutoPilot!
You will need to set the NMEA Output menu to the “On” setting.
You will need to connect the TR1 to the NMEA output from the GPS Receiver wiring, but the GPS Receiver you have and the NMEA 0183 sentence prefix that the TR1 will use will determine how/where you will make this connection. Look in the TR1 operations manual and see whether it states anything about NMEA 0183 sentences with the $IN or $GP sentence prefix and let us know. You also need to pull the black plastic cap off of the NMEA pigtail wire. This is the second shorter cable that comes out of the GPS Receiver’s connector. Let us know what color wires are there.