Thanks for the input. I've got all the physical stuff, and the wiring, done successfully. I did get position lock (plane is not yet flying) by folowing Shawn's advice on Main Talker. As I mentioned earlier, I'm stuck with using the input side of the same port that feeds the transponder, so I'm limited to 9600 baud.

Any idea which sentences are the *minimum* required for the EFIS to do it's thing? Or if a somewhat slower update rate (say, 2.5 hz) will still allow smooth synthetic vision action? I currently have only GPRMC, BPGGA & GPGSA enabled, with updates set to 5 hz. Looking at the text strings, I'm getting 5 sentences per second each for the three sentences listed, most of the time, but every few seconds it'll drop a sentence or two, as expected at 9600 baud.