Access Control System Using Smart Phone

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 smartphone with a predetermined scanning app 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 transmitter to an access control unit. A data base of the access control unit can be interrogated to determine if that smartphone identifier is authorized to open the designated door. If authorized, an access command can be transmitted to a local access control module which can release a locking mechanism for the respective door.