Apartment building door intercom system - has unit receiving intercom signals to provide call signal within each apartment

摘要

The intercom system has a call bell unit adjacent the entrance door and a communication unit in each apartment of the building. A central coupling network allows communication between the call bell unit and the communication unit within the apartment corresponding to the actuated bell. An audible call signal is provided at the communication unit within the apartment by the element receiving the intercom signals. The call bell unit is pref. connected via the coupling network to the telephone in each apartment supplied with a call signal via an oscillator in response to actuation of the respective call bell.