From a bit more reading and research today, I have copied and pasted a couple interesting things
the garmin 94sv only has 4 wires coming out of CP for its nmea0183 capabilities.
The Garmin echoMAP series maintains the Garmin non-standard color coding, but offers only one interface:
DEVICE: GARMIN echoMap 40/50, echoMap CHIRP 70/90 Series
TALKER A = Blue
TALKER B = not provided
LISTENER B = not provided
LISTENER A = Brown
Other head units eg 942
The Garmin echoMAP 702/742/902/942 series appears to improve the NMEA-0183 interface by providing the recommended differential signals, but a non-standard wire color code is still used:
DEVICE: GARMIN echoMap 702/742/902/942
TALKER A = Blue
TALKER B = Gray
LISTENER B = Violet
LISTENER A = Brown
RULE 1: LISTENER connects to the TALKER of the other device with the same A/B notation.
With that, My ? would be, does the tr1 use "B" notations , were your head unit can only send and receive "A"
Or as the tr1 manual states, The autopilot expects to see, at least, the NMEA data sentences $GPRMB and $GPRMC at 4800 baud.
so another ? for garmin, if the tr1 will work with either A or B notations, is my 94sv capable of sending GPRMB GPRMC sentences.
Again I hope this helps you .
Warren
information found here
http://continuouswave.com/forum/viewtopic.php?f=9&t=816