An anti-vehicle-thief apparatus registers specific ID codes of a plurality of keys, and determines validity of a key, for example, in accordance with an operation of the key 1 including a transponder having one of the registered specific ID codes. The anti-vehicle-thief apparatus registers a code specific...http://www.google.com/patents/US6008722?utm_source=gb-gplus-sharePatent US6008722 - Anti-vehicle-thief apparatus and code setting method of the apparatus
