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

A method for controlling access of individuals to an area comprising the steps of:

• transmitting control data and authorization data in a predetermined format from a data carrier to a stationary reading device via an RF signal, said reading device being programmable to identify one of a variety of formats;
• programming the stationary reading device with the control data to recognize the predetermined format of the authorization data;
• relaying the authorization data to a central evaluating unit unaltered;
• comparing the authorization data to check data contained within the central evaluating unit;
• and
• instructing locking means to allow access to the area if the authorization data matches the check data.

An access control system for controlling access of individuals to different areas, comprising:

• at least one portable, programmable RF transponder, each portable, programmable RF transponder being assigned to and carried by an individual and storing:
• i. allocation data;
• ii. control data identifying an authorization data format and a predetermined number of active bits within said authorization data format;
• iii. authorization data comprising a predetermined number of active bits organized in said authorization data format
• a plurality of reading devices, each reading device corresponding to one of the different areas and including:
• i. an EEPROM, containing an allocation code and a comparator;
• ii. a RAM memory for storing said control data;
• iii. transmission means programmable by said control data stored within said RAM memory for transmitting said authorization data;
• central evaluation means including check data;
• a first data communication line connecting each of said reading devices to said central evaluation means;
• a locking device assigned to each of said reading devices for restricting access to the corresponding area;
• a second data communication line connecting each locking device to said central evaluation means;
• wherein said portable, programmable RF transponder is brought within RF coupling proximity to one of said reading devices so that energy is transmitted from said one reading device to said portable, programmable RF transponder;
• wherein said allocation data is transmitted to said one reading device and said comparator compares said received allocation data with said allocation code contained within said EEPROM;
• upon a favorable comparison, said control data is transmitted from said portable, programmable RF transponder and stored within said RAM memory;
• said control data programming said transmission means to transmit the predetermined number of active bits of said authorization data in said authorization data format to said central evaluation means over said first data communication line without random fill characters;
• wherein said central evaluation means compares said received authorization data to said check data, upon a favorable comparison, said central evaluation means instructs said assigned locking device, over said second data communication line, to provide access to the corresponding area.

A method of controlling access of individuals to different areas, comprising the steps of:

• positioning a portable, programmable RF transponder within RF coupling proximity to a reading device assigned to one of the different areas so that energy is transmitted from said reading device to said portable, programmable RF transponder;
• transmitting allocation data from said portable, programmable RF transponder to said reading device;
• comparing said transmitted allocation data to an allocation code stored within an EEPROM, upon a favorable comparison control data is transmitted from said portable, programmable RF transponder to said reading device and stored within RAM memory;
• programming a transmission device within said reading device with said control data to transmit a predetermined number of active bits within a predetermined format;
• transmitting unaltered authorization data from said portable, programmable RF transponder to a central evaluation unit via a first data communication line, said authorization data consisting of a predetermined number of active bits within the predetermined format;
• and
• comparing said received authorization data with check data, upon a favorable comparison, said central evaluation unit instructing a locking device, assigned to the one area, via a second data communication line, to provide access to the one area.