The Aiphone AX-8MV audio/video master station for AX Series connects to up to seven additional master stations, up to eight door or sub-master stations, and a central exchange unit (sold separately) to create a security system with video feed throughout a building. The 3-1/2″ LCD color monitor immediately displays video feed from the Aiphone AX Series video door station (sold separately) during an incoming call to aid visitor identification. Up to seven Aiphone AX-16SW selectors (sold separately) can be used to connect a total of 112 additional sub-master or door stations to the system. The door-release button works with an electric strike or magnetic lock (sold separately) to remotely unlock the entrance for the visitor. Each master, sub-master, and door station has its own labeled button on the master station to enable selectable and direct calling, and each button has an LED that indicates which one is calling. The all-call button broadcasts to every master station connected in the system. The privacy button prevents other intercom users in the system from overhearing a conversation with another intercom.