Audio set Siedle Compact in 1+n technology with the functions of calling, speech, and door release. Number of integrated call buttons: 1. Each Compact set can be extended by an additional indoor station per call button and supplemented by a secondary signal device. Scope of delivery includes the Siedle Compact audio door station (brushed stainless steel), standard in-house telephone, transformer, and integrated door loudspeaker. Speech volume is adjustable. Number of integrated call buttons available: 1 (CA 812-1), 2 (CA 812-2), 4 (CA 812-4). Backlit nameplates can be changed at the front, and there is a backlit info sign for house number, logos, opening hours, etc. Designed for surface mounting with brushed stainless steel trim. Features of the indoor station HTS 811-0 include a door call as a 3-tone call and a storey call as a 2-tone call, possible in the Compact set with Zert 811-0. Integrated call silencing is available via volume control, and call volume is continuously adjustable from outside via volume control up to a maximum of 83 dB(A).