Abstract: An electronic lock of the type which can receive a plurality of electronic keys is disclosed. Each of the electronic keys has a unique key code associated therewith, one of the keys being a control key, the remaining keys being opening keys. The lock includes a read only memory for storing a control code corresponding to the key code associated with the control key and an erasable memory for storing a set of opening codes. The lock further including a control circuit which compares the key code of each key placed in the lock to both the control code and the opening codes. The control circuit opens the lock when the key code of a key placed in the lock corresponds to any one of the opening codes and changes the set of opening codes stored in the erasable memory when the control key and one of the opening keys are sequentially placed in the lock.

Abstract: The disclosure relates to the computer art in general, and in particular to an identification device of the key-board type which includes a rectifier for both supplying current to the device and for supplying a trigger signal to a pulse generator having several outputs. Upon receipt of the trigger signal, the pulse generator generates a predetermined sequence of pulses on its outputs which are connected to a combination circuit which has two outputs. The pulse generator is operative to generate a train of pulses, each pulse of the train being applied to a respective one of the outputs as a function of a code which identifies the device. The pulses appearing at these two outputs are inductively transferred to a detector which thus receives a pulse train containing a predetermined number of pulses, the polarity of each of the pulses being representative of a binary number constituting the identification code of the device.