Garmin GTX 327 using D100 for alt enc - Opinions?

[matt.hocker]

I have a Dynon EFIS-D100 and a Garmin GTX 327 transponder. The transponder currently uses its own dedicated altitude sender which works fine but occupies a space behind my panel that I'd like to use for a steam gauge VSI.

I read the manual for the D100 and the GTX 327. It appears that I can input gray code altitude input to the Garmin by connecting pin 13 of the D100 to pin 19 of the GTX 327. The D100 apparently can be configured to output the correct serial data using "Format 4" which the Garmin requires.

My question is, other than freeing up the space from the altitude encoder, are there any pros/cons of using this setup versus a dedicated encoder?

Thanks

 

[Dynon]

Pro: Your D100 isn't a "blind" encoder. That is, you can spot check what it's outputting just by setting your altimeter to 29.92. In contrast, your dedicated encoder has no way of feeding back to you, except through ATC's complaints and your periodic required tests.

Con: Very rarely, shops will demand that the encoder be certified. The regs don't require it, in our view, but, we can't convince 100% of people of that.