Access control system where the card controls the transmission format of the card reader

摘要

An access control system for controlling access of individuals to an area having at least one programmed data carrier. Each programmed data carrier is assigned to an individual and has a programmed memory including a predetermined number of active bits within a bit allocation map defining authorization data specific to the individual. The programmable memory also has control data including an entry representative of the predetermined number. A stationary reading device is installed adjacent to the area for receiving the control and authorization data from the data carrier. The stationary reading device has uninitialized and unprogrammed programmable reader memory. A central evaluation unit includes check data and is coupled to the stationary reading device. The control data programs the reader memory so that the reading device recognizes the predetermined number and relays authorization data unaltered to the central evaluating unit. The central evaluating unit allows access to the area if the authorization data matches the check data.