Abstract: An AC current sensor comprising a generally C-shaped main coil with a fixed gap between its ends. A pair of compensating coils are positioned at fixed locations in the main coil's gap. The longitudinal axes of the compensating coils lie on an imaginary straight line which extends between the centers of the main coil's ends; and their electrical centers are each spaced the same distance from their respective ends of the main coil. A compensating coil gap is defined between the electrical centers of the compensating coils. The main coil defines a measuring recess in which the sensed AC current carrying conductor is located when a measurement is taken. When the ratio of the size of the main coil gap to the size of the compensating coil gap is equal to the square root of three, the AC current sensor's accuracy and outside signal rejection increase most rapidly with increased distance of the sensed AC current carrying conductor from the compensating coil gap, and the AC current sensor's size can be minimized.

Abstract: An apparatus for unloading a length of film from a cartridge, trimming the ends from the film, splicing the leading edge of the film to the trailing edge of the previously unloaded film, placing an identifying mark on the film and on an envelope and winding the film on a magazine. The unloading device allows the film to be removed from the cartridge by manually pulling the sheet of backing paper from the film in the daylight while shielding the film from light. The cartridge is locked to the loading device until all of the film in the cartridge has been loaded through a film guide into a storage box. The leading edge of the film is then trimmed by upward movement of a cutting blade allowing the film to advance through an aperture in the cutting blade until the trailing edge is trimmed by downward movement of the cutting blade.

Abstract: The system includes up to four communication links, a separate link selector for each link, and a separate link scanner for each telephone station. The system is suitable for usage with conventional dial pulse or tone selective key telephone sets.

Abstract: The system includes a central station console and one or more remote station modules. Corresponding message-waiting indicators mounted by the central station console and each remote station module are accessed and controlled from the central station on a selective individual basis; but can be controlled alternatively from the remote station modules in order to indicate message-received. Corresponding do-not-disturb indicators mounted by the central station console and each remote station module are controlled exclusively from the latter. For telephone application, the do-not-disturb indicators additionally may be operated in a flashing mode when the associated telephone set assumes off-hook condition in order to provide call status indication.

Abstract: Apparatus for gauging location of a movable element in relation to an end of an elongated impulse wave energy propagative member employing a sensing transducer adjacent one end of the member to sense first the direct impulse and thereafter the indirect impulse that is reflected from the opposite end. Processing of the sensing transducer responses and sequentially programmed digital measurement of time intervals associated with the duration and time relationship of such responses according to logic equations affords the desired location indication with automatic compensation for ambiently caused variations in shock wave propagation velocity in the member on repeating cycles of operation and with measurement accuracy independent of undue precision requirements in location of the sensing transducer in relation to the adjacent end of the member.

Abstract: Processing apparatus for automatically cutting (or otherwise operating on) a filmstrip during advancement thereof into positions precisely related to the cutter by referencing to the transversely oriented center lines, rather than leading or trailing edges, of marks or cuts longitudinally spaced along an edge of the filmstrip. Sensor means having a mark detector and responsive to duration of a first time interval initiated by the mark's leading edge passing the sensing detector and terminated by the mark's trailing edge passing the detector, computes the correct filmstrip feed distance from the true center line of each mark to the associated next stopping point wherein the filmstrip is presented to the cutter. It does so by counting the pulses controlling filmstrip feed rate established by a stepping motor drive, after first dividing the pulse frequency in half during only said first time interval, such count continuing to a preset number selected to be reached after said first time interval.

Abstract: A camera film locating feed system for processing of film strips utilizing locating holes in the film that have or tend to undergo trailing edge damage due to mishandling of the camera when the film is being advanced from one frame setting to the next. In feeding such film in the processing device a selectable control means detects film positioning by reference to the leading edge of each locating hole with the film in one orientation in the processor, and by the lagging edge with the film inverted or oppositely oriented in the processor, and rejects false detection control signals from certain kinds of locating hole damage by the delaying action of a control means gate.