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.