A locking system which comprises a microcomputer controlled lock (10) with multiple level keying, i.e. multiple keys (34) having different functions in the locking system. A key reader (38), for example punch card or magnetic type, reads key code into the microcomputer. A read/write memory (217) has a predetermined number of assigned key codes stored therein and a read-only memory (215) has a control program stored therein for control of the microcomputer. An electrically controlled actuator (42) for the locking means is coupled with an unlocking output of the microcomputer. The control program comprises a main program and a plurality of subroutines each stored at a different location in the read-only memory. A function table (219) has a number of pointers each of which points to the memory address of one of the subroutines. The number of pointers in the function table (219) is equal to the number of locations in the key code memory (217). Decoding means operative under program control in conjunction with a control code (102) on the key (34) points to selected locations in the key code memory (217) and the function table (218) corresponding to the control code (102). A microcomputer (112), under control of the main program, compares the primary (104) and secondary key codes (106) from the selected key (34) with the assigned key at the location in the key code memory (214). If there is a match, the microcomputer then operates under the control of the subroutine at the memory address pointed to by the function table (219) to execute the function of the selected key (34).
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