Abstract: The present invention relates to a system (10) operable to control access to different physical spaces, each provided with an electrical locking device (121, . . . , 12n), with the aid of a programmable, mobile unit (14). The system (10) comprises an authority means (16) operable to issue access rights connected to the programmable, mobile unit (14) in the form of an authorizing data (AD), which authorizing data (AD) is sent to an authorization means (18) connected to the authority means (16), and operable to generate an alpha-numerical key for the mobile unit (14), and to send the alpha-numerical key and a unique identifier of the mobile unit (14) to an operator (20), which is connected to the authorization means (18). The operator (20) is operable to send the alpha-numerical key to the mobile unit (14) identified by the unique identifier.