The DoorBird D21DKH is suitable for the locations where you want to connect the door station to 19-100 different door terminals, e.g. apartment buildings.
Each property can install DoorBird mobile application on up to eight different smart devices (phone, tablet…). With the mobile app downloading and usage being completely free of charge, and the fact that there is no need for a separate indoor station, the cost of an entire door phone system consists only of the one (or several) outdoor stations.
Doorbird door phones are quick and easy to install and can be powered with PoE.