US Patent 10944940 Intercom system for collective housing

An intercom system for collective housing comprises a main entrance station with a camera, a residential entrance substation with a camera and a residential master station for each residence in the housing, a storage unit that stores videos (V1) of visitors shot by the camera of the main entrance station by associating the videos with residence IDs of the respective residences to visit, and a control unit. The control unit includes a check unit that checks the videos (V1) against a video (V2) shot by the camera of a residential entrance substation. If the check by the check unit indicates a match, the control unit compares the residence ID associated with the match stored in the storage unit with that of the residence in which a call button of the residential entrance substation has been operated. The operation of the call button is invalidated if the IDs are different.