Great if you know what you're doing, or wants to replace a supported device.

I have the device (with additional button option) bought an old, broken station in an apartment building to replace, and I already knew before ordering that the Siedle HT411 * unsupported * readily.

Nevertheless, I have purchased the product, with the "extra button".

Problem with my old intercom is that these various ground lines for audio and door opener / possesses signaling that Urmet 1133/15 but only supports a mass.
Now you can see the two ground lines is not simply short-circuit; because there is a reason why there are two. That's why you can not use the door release button on my installation (to replace an HT411 in an apartment building).

The actual terminals on the board I use now only the audio portion (audio in / out / audio mass; terminal 1,2 and 6 - without guarantee!).

Door Opener voltage Buzzer / Summer mass and Summer-voltage I now have "free wired" with the buzzer module and the auxiliary button and the Summer-breaker, and the corresponding wiring cut with the board.

With the restriction that the door opener now on the button at the bottom right is instead on the door release button now seems to be going all; I'm no electrician; everyone who buys the items should know himself what he is doing!