When a visitor presses one of the outdoor panel pushbuttons, the built-in camera is connected and the image captured outdoors appears on the monitor screen. Connection takes place automatically with no need to activate the equipment, which is one of the essential elements of video door entry. As of this point, the person inside the building can open the door if they wish or begin a conversation, which is usually secret (cannot be heard by other users of the same facility). The equipment also disconnects automatically after a set time has elapsed. The video entry system as a whole runs on low voltage energy from the building's trunk