Patent attributes
A door access control system associates a unique passive identifier with each one of a plurality of doors for which controlled access is desired. Each of the identifiers can be attached to a location adjacent to each respective door. A smart phone with a predetermined scanning application can scan or read a respective identifier of a door for which access is desired. A representation of the door identifier along with an identifier of the smart phone can be transmitted to an access control unit. A data base of the access control unit can be interrogated to determine if that smart phone identifier is authorized to open the designated door. If authorized, then an access command can be transmitted to a local access control module that can release a locking mechanism for the respective door.