Odyssey Garmin GPS 175 Integration

[Mmacey]

Hello
I am connecting an Odyssey G2 (Firmware 3006) with a Garmin GPS 175.
I have followed the April 2014 Iefis/Odyssey/Voyager integration guide.
I have Trio EZ autopilot servos connected directly to the Odyssey via serial connections through a com extender. they are selected in the set up menu as internal auto pilot.
There is Airinc communication between Odyssey & Garmin with the exception of label 121 (roll steering)
Lateral steering pass-through has been selected in the ARINC menu.
During Garmin start up BIT test
I see CDI half left and VDI half down,
OBS on Odyssey can be rotated and will show correctly on Garmin, but the flight director test does not work and label 121 shows not valid on Odyssey Diagnostic Airinc activity page.
If I select flight director + Airinc external auto pilot in the Auto pilot setup menu, then label 121 does become active and shows the repeating 1 degree increments up to 5° right bank at 1 second intervals during the BIT test on the Airinc activity diagnostic page. This doesn’t help since no external auto pilot exists.

What I am hoping to accomplish is that during an LNAV GPS approach the CDI and flight director will automatically sequence with the individual legs of the approach As outlined in the integration guide.
Any ideas??

Thanks
Mike

[rainier]

Use the internal navigation as source for your AP - even if it originates from the Garmin, i.e. the Garmin sets your HSI and the AP follows that.
Don't bother with label 121 pass through - that assumes you have a ARINC bases AP connected (in this case the horizontal and vertical steering commands from the Garmin can be passed through to the AP unchanged). However this is limited in functionality. It is better to use the navigation systems in the EFIS (for example you can do heading bug steering) and use the Garmin as source for GPS related navigation driving the EFIS HSI.