Building controller and interphone system

An intercom system which is to be used in an apartment complex which is configured by a plurality of residential buildings and a centralized building that can communicate with the residential buildings, wherein

• each of the residential buildings includes:
• residential room master devices which are disposed in residential rooms, respectively;
• a plurality of terminal devices which can communicate with the residential room master devices;
• and
• a building controller which communicably connects the residential room master devices of the residential rooms in an own building, with the plurality of terminal devices, and
• the building controller has:
• first identification information that, when one of the residential room master devices is called from the centralized building via the building controller, is used in recognition in which the centralized building recognizes the building controller;
• and
• second identification information that, when the one residential room master device is called from the centralized building via the building controller, is used in recognition in which the one residential room master device recognizes the building controller as a virtual terminal device that is different from the plurality of terminal devices.