A security system includes a microcomputer with an auxiliary read-only memory and a key device including a similar read-only memory, each of the read-only memories containing corresponding pluralities of corresponding binary combination codes. Under the control of the microcomputer the codes are read...http://www.google.com.au/patents/USRE33873?utm_source=gb-gplus-sharePatent USRE33873 - Microcomputer controlled combination lock security system
