Thanks Ray,
unfortunately I can't find any screw on the knobs. Maybe I should pull on them with more force. I would, If I knew that that is the way to get them off. The normal strength to pull off knobs of commercial audio equipment is not enough. So I'm afraid to damage the panel.
The SV-Intercom-2S is shipped with 2 front plates, a horizontal and a vertical plate. I can't find a discription how to interchange the plates. Neither in the installation guide nor in a forum post. There is no obvious sign, how to remove the knobs to reach the nuts to loosen the plate. I don't...