Siedle Compact audio set in 1+n technology with the functions of calling, speaking and door opening, the IQ in-house telephone is designed for mobile expansion using the Siedle app. Number of call buttons: 1 Each Compact set can be supplemented with an additional indoor station or a secondary signal device for each call button. The ZERT 811-. accessory is required for the storey call. Scope of delivery: . Siedle Compact audio door station (CA 812-1 E) . In-house telephone for 1+n technology with WLAN interface . Transformer (TR 603-.) . Power supply unit (PSM 1 12 24)