Video door-phone (also known as video door entry or video intercom) is a stand-alone intercom system used to manage calls made at the entrance to a building (residential complex, detached family home, workplace, etc.) with access controlled by audiovisual communication between the inside and outside. The main feature of video door entry is that it enables the person indoors to identify the visitor and, if (and only if) they wish, engage in conversation and/or open the door to allow access to the person calling. Video door entry systems are commonly found integrated with different access control systems. This means that elements are installed in the same outdoor panel to allow certain previously authorised users to access the premises. The most common means are proximity cards, fingerprint readers, a keypad for secret numbers or even Bluetooth triggered by mobile phone.