Confirmed. the HC800 has a Line In AND a line out. You will need to set the Audio endpoint for the outdoor zone to the HC800 and then the 800 will do Volume..

One thing you might need to keep in mind. THe 800 is going to A/D then D/A the audio... I Think..... so the outdoor zone will be delayed from the Abus Speakers.

Confirm with C4 that even if the 800 is the only end point it still digitizes the audio. Pretty sure it will. I know you can set SPeakerpoints to Skip these steps.. I dont think you can on an HC800.