This system is mainly used in the Apartments. In multi-apartment video door phone system we can restrict unwanted entry inside the apartment

If there is a visitor for a particular apartments he/she has to press the button in the main console, where the name of the owner in the particular apartment is displayed, and there communication is done through audio, if the owner of the particular apartment wishes the visitor to come, he/she can press the door release button in the handset and the main door is opened.