When connecting the DFC90 to the Aspen PFD, the Aspen may require an 'unlock'. This is the responsibility of the shop and not Avidyne.
The IFD is providing all of the deviation data to the Aspen via ARINC 429 (digital) and the Aspen then sends that digital data to the ACU, which processes the information and outputs the analog equivalent to the autopilot. The way the Aspen does this is dependent upon what mode is selected on the Aspen. For i…