Speaker detection instead of ring detection, comelit 2708w

I’m trying to connect my comelit 2708w on the analog way, on an extra 2708w set with the same adres set and some ironing.

Only I need to set the opener to speaker detection instead of ring detection, ring is on the speaker and a low voltage.

Green goes to + speaker.
Yellow / Red on connection + wire for speaker.

Blue and Purle I connected on the open switch and works fine.

How can I do that so it will work with ring to open.