Patent ID: 6332572
Filing Date: 2001-12-25
Classification: B60R,G07C

Abstract:
A key code correlation security arrangement, comprising:a key;a transponder associated with the key, the transponder having a memory for storing a predetermined key code, and means for transmitting that key code in response to a key code request transmitted thereto; andan interrogator for transmitting general and specific key code requests to the transponder, the interrogator having a memory for storing one or more predetermined key codes identifying authorized keys, means for receiving a key code from the transponder in response to a key code request, and means for comparing a received key code with the key codes stored in interrogator memory, the interrogator also having a key code request changing means for differentiating key code requests for a plurality of key codes, and interference determination means for determining whether or not answer signals responding to a key code request interfere with one another, andwherein if the interference determination means has determined that there is interference of two or more key code responses from transponders in response to a general key code request, the interrogator then transmits specific key code requests that are specific to individual keys, and compares responses received with the key codes of such specific key code requests.