Garmin 335/345 GPS out...
 

If you buy the Garmin 335/345 (ADS-B) with GPS, does it have a GPS out channel that could drive the Dynon Autopilot, or some other autopilot for that matter?

Michael-

The built in WAAS GPS is just a position source. (It knows where it is but not where it is going.) You would need a GPS navigator to drive an autopilot.

Another question might be, does it have a GPS out channel that could provide a position source to a 406Mhz ELT?

You could use something like the Aera 660 to drive your non-Dynon auto-pilot (e.g. TruTrak) and link the 345 via serial or Blue Tooth to the 660 for wx and traffic.

If you have a Dynon system, you would want the Dynon AP servos, transponder and GPS 2020 antenna plus the new ADSB-472 for an IN source of wx and traffic.

Lots of Q&A on the ACS site, where the ELT question has already been posed.

Q: My ELT (an Artex ELT 345) needs GPS position information via RS-232. Can the WAAS-equipped GTX-345 supply that information via one if its serial ports?

A: Garmin recommends connecting your ELT with a GPS such as the Aera 660 or GTN 650.

Was looking into how to intergrate the Artex ELT 345 with the Garmin G3X.
Below is what I found in the Garmin Manual. (Use either a GDU or GTN/GNS).
Artex has the wiring diagram for the ELT 345 Cockpit switch via the RS-232 connector.

2.1.1.21 Emergency Locator Transmitter (ELT)
The G3X system can provide NMEA 0183 formatted GPS position data to an ELT, via an RS-232 output from a GDU display. In an installation with a GTN/GNS navigator, an RS-232 output from the IFR GPS using the ?Aviation? data format may be preferred. For further ELT interface guidance, consult the ELT manufacturer.