Abstract: A system and apparatus for encoding magnetic information on a magnetizable substrate where the substrate is liable to be moved erratically, e.g. manually, past a magnetic head. Two parallel tracks are provided on the substrate and the first is encoded with binary information conventionally with shorter spaces between change of field representing one binary digit and longer spaces representing the other digit. The other track is encoded using changes in field on the first track as a timing reference such that any change of field on the second track substantially coincides with a change of field on the first track and one digit of the binary pair is represented by no change in field as the field changes on the first track while the other binary digit is represented by a change of field coincidentally with a change of field on the first track. The system and apparatus are eminently suited for use in parking meters where a power source to drive a card consistently past a reading head is not available.

Abstract: A method for clearing unlocking key codes in an electronic locking device in which the unlocking circuit is arranged to be actuated when the code of a magnetic card read by the card reader agrees with an unlocking key code set in the memory, the method comprising using a first clearing card which will function only when the door associated with the locking device is open and a second clearing card which will function only when the door is closed, setting the codes of the first and second clearing cards in specified separate addresses in the memory in the code setting mode for setting the codes of the clearing cards in the processing unit (CPU) of the electronic locking device, determining whether the door is open or closed in the normal operation mode of the CPU, and clearing the unlocking key codes only when the code read by the card reader is identical to the code of the first clearing card set in the above-mentioned manner and the door is open, or when the code read by the card reader is identical to the c

Abstract: An electronic locking device which is particularly useful for safes in a hotel room comprises an unlocking circuit actuated when a code on a magnetic card which acts as the "key" is read by a card reader forming part of the device agrees with an unlocking code stored in the memory of the device. The unlocking code from the card is set in memory when the memory is enabled and the magnetic card is loaded into the card reader for a plurality of times within a relatively short pre-selected time interval.

Abstract: A power source capable of providing a constant DC output when supplied with one of a range of AC inputs. Converter means providing a number of outputs of differing voltages each proportional to the input voltage. A number of parallel circuit lines each connected to one of those outputs. Each parallel circuit line including a rectifier, a maximum voltage regulator and a non-return current device. The outputs from those lines being connected to a common output to give the constant DC voltage supply.

Abstract: A door lock in which the lock bolt is not retracted by direct action of the handles but is instead retracted by slide members acted upon by the handles, the slide members having means for engaging a further slide which carries the bolt. One of the engagement means includes an electromagnet and an engagement member. The engagement member engages the bolt carrying slide only when the electromagnet is energized, which occurs when an appropriate key has been inserted into the lock and verified.