Resettable locks have been produced in the prior art for hotels and motels, which can be reset after each room occupancy. In this way, lost or stolen keys are ineffective to gain access to the room at a future date. Such a resettable lock is described, for example, in U.S. Pat. No. 3,938,358.
The keying process of the present invention finds particular utility with resettable hotel or motel locks of the type described, for example, in the aforesaid patent. The key is constructed to permit the establishment to change the lock of any room after each occupancy, and yet to maintain an efficient system for detecting prior keys used for a particular room and for removing such keys from service.