Abstract: A circuit for use with a subscriber loop interface circuit (SLIC) to detect the hook/switch status of the telephone handset driven by the SLIC. Responsive to metallic current flowing through the handset when the telephone is taken off hook, a voltage is derived which exceeds a threshold level as well as a current is produced which is proportional to the value of the metallic current. Whenever the produced current level is less than a predetermined value in conjunction with the threshold level being exceeded, a comparator threshold circuit is rendered operative to produce a signal indicative of the hook status being in a closed switch state. With the hook being in an open switch state, the voltage is caused to be less than the threshold level wherein the comparator threshold circuit is maintained in an non-operative state.

Abstract: An electronic tone ringer for use in a telephone instrument to respond to ringing currents to generate an output tone electronically is described. A controlled breakdown rectifier bridge is placed across the input line to produce a d.c. output in response to ring input. The d.c. output is fed to an oscillator to produce a signal which is fed to a piezo-electric transducer to produce output tones. A number of safeguards are built into the circuit to prevent random noises from being fed to the oscillator. Further, the controlled breakdown bridge provides voltage clamp action to prevent spikes of voltage from damaging the circuit.

Abstract: A multi-purpose telephone holder is adapted to hold or position a compact telephone subset in three different orientations. The unit comprises a first tray module which essentially is a relatively rectangular housing configuration having sloping sidewalls, a back wall, an open front end and a bottom surface. A second assembly is a clip mechanism which is adapted to coact with the bottom surface of the tray and has two side retaining arms and two bottom arms for accommodating the subset in a vertical position. Suitable apertures are located in the bottom surface of the tray to enable the clip and tray to be positioned on a wall above a standard baseboard telephone jack. A third component consists of an adapter wall plate which has a peripheral flange for coacting with corresponding flanges on the bottom surface of the tray.

Abstract: A timed telephone ring silencer device for selectively disabling the ringer mechanism of an attached telephone for a predetermined timed interval during a time when the user does not wish to be disturbed by telephone calls. The silencer device contains a modular cord and attached plug for connecting the device to a telephone line and a modular jack for connecting a telephone to the device. The silencer device includes a quartz-controlled clock module for providing timing and selection of a timed silent interval, when the ringer mechanism of a cooperating telephone is disabled, as well as traditional clock, calendar, and alarm functions. Also provided are switches which are used to manually initiate a timed silent interval and to immediately enable the ringer mechanism of an attached telephone, if the user wishes to return his telephone to normal operation during a timed silent interval.

Abstract: Telephone call progress tones are identified by measuring the periods of their envelope cycles in the range of 20 to 200 Hertz which are due to the difference frequency of the signals used by phone company to form the call progress tones. The periods of the envelope cycles are classified, and a decision is made by a programmed microprocessor by comparing the data derived from the unknown signal to what is expected for known call progress calls of many telephone companies. In making such decision, the several period measurements are accumulated in bins, and the bin reaching the largest total is used to develop a representative period which is examined, if various other criteria are met, to identify the call. In this process, substantially regular envelope cycles are selected, and noise is rejected. An answer to the call is detected by this technique.

Abstract: Noise suppression apparatus is interposed between the transducer and the amplifier of a hearing aid, allowing the user to adjust the operation of an automatic level control circuit to provide suppression of background sounds with negligible effect on audibility of close-in sounds.

Abstract: A combination radio and tape player is disclosed which includes a signal equalization selector wherein the audio program selection switches which select either an AM or FM radio mode or a tape player mode of operation also simultaneously select various different sets of stored control signals which implement predetermined audio signal equalization in accordance with the type of audio mode of operation (program) that was selected. This is accomplished by the use of a random access memory which stores three pluralities (sets) of control signals, each plurality of control signals corresponding to a predetermined desired equalization for either the AM, FM or tape player modes of operation of the combination radio and tape player. Manual controls are provided which allow selective adjustment of the equalization provided in any of the AM, FM or tape player modes of operation.

Abstract: Energy in a received signal is distinguished as being whole band energy or partial band energy by comparing an average value of the received signal to a modified magnitude value of the received signal. When the modified magnitude value exceeds the average value, the received signal includes whole band energy, otherwise the received signal includes only partial band energy.

Abstract: Circuitry is provided for distorting an audio signal, useful in providing a "dirty" sound to an electric guitar simulating a vacuum tube amplification thereof. The circuit includes components for simultaneously changing the amount of distortion introduced by a clipping circuit and the amount of gain boost provided at a preselected narrow bandwidth. Addition of such gain boost leads both to increased clipping of the audio signal and to reduced frequency response, at both low and high frequencies. A separate volume control is provided for broad band gain adjustment. Independently operable control switches permit insertion or elimination of the distortion, and insertion or elimination of a brightness circuit boosting high frequency response of the circuit.

Abstract: A camera exposure mode setting device including a dial which can be moved to select a number of different exposure modes, one of which is controlled by a self-timer circuit in the camera. The device also includes circuitry coupled to the dial which operates to prevent the self-timer circuit from operating unless the dial is maintained in a self-timer exposure mode position. In a preferred embodiment, a push button extends from the dial, the button being arranged to prevent the dial from being moved to select the self-timer mode unless the button is first pushed down by the user.

Abstract: A system for transferring a load from a first to a second AC power source, including a monitor for sensing both power sources and producing an output signal when the differences in voltage, frequency, and phase between the two sources are within prescribed limits. Contacts close, in response to the monitor output signal, to connect the second power source to both the first power source and the load. Other contacts open, to disconnect the first power source from the second power source and load, but only after the second power source has been connected to the first power source and the load. The contact arrangement may include an automatic transfer switch and separate contacts in parallel with one or both sets of transfer switch contacts, or it may involve two independently operable contactors, or it may involve a four position switch.

Abstract: A stereophone includes a headband which supports cup assemblies at each of its ends. The cup assemblies can be pivoted to a transport position in which they are enclosed within the headband. The ends of the headband may be fastened together to retain the cup assemblies in this position.

Abstract: A laser recorder device in which many levels of half-tone densities are accurately produced with smooth transitions between areas of different densities. An input signal is sampled with a sampling pulse in response to which digital output values of a predetermined function of the input signal are produced. Pulses are applied to a semiconductor laser beam source with the number and frequency of the pulses during a preset application time being determined in accordance with the magnitude of the input signal.

Abstract: A telephone call monitoring apparatus is described for monitoring a subscriber's telephone to determine the time of day in which incoming or outgoing telephone calls are made and the duration of the calls. Additionally the apparatus determines and records the telephone number of the "called" telephone. The apparatus is responsive to the frequency, duration and pause between ring back signals placed on the telephone to determine the estimated time that the call is answered by the called telephone.

Abstract: First and second sound channels are provided for processing audio signals. Each sound channel includes means responsive to a D.C. control voltage for controlling the volume of the audio output signal of the channel. A volume control potentiometer is coupled across two terminals of a source of supply voltage and a D.C. volume control potential is developed at a tap of the potentiometer. The volume control potential is applied to a control electrode of a controlled current path. The controlled current path includes the parallel combination of a first voltage divider and a second, variable voltage divider. A tap of the first voltage divider is coupled to the D.C. control input of the first sound channel, and a tap of the second voltage divider is coupled to the D.C. control input of the second sound channel. By adjusting the second, variable voltage divider, the control voltage provided by the second voltage divider may be set to equalize the D.C. volume control characteristics of the two sound channels.

Abstract: A lock for securing a telephone instrument against unauthorized use includes a key-operated cylinder extending through a wall of the housing of the telephone instrument and including a cam movable between locked and unlocked positions for engaging the line switch of the telephone instrument in the locked position and maintaining the line switch in a disconnect position so long as the lock remains in the locked position.

Abstract: Ink jet recording apparatus includes a guide member provided in parallel to a transversal direction of a recording sheet, a carriage having a recording head and adapted to move on the guide, a signal generator provided in parallel to the guide, and a control unit for causing the signal generator to detect position and speed of the carriage.

Abstract: Magnetic memory element for transport ticket or credit card, comprising a support and at least one ferromagnetic layer containing at least one piece of information recorded therein and a layer of a non-magnetic diffuser in contact with the ferromagnetic layer to irreversibly destroy the magnetism of the ferromagnetic layer when the element is heated.

Abstract: The body for a telephone unit is designed to permit easy removal for maintenance and for initial assembly. The escutcheon plate which is a close fit to the dial is fitted in an oval hole which allows it to move on the body to clear the dial on removal of the telephone body.

Abstract: The present invention relates to a system for exposure measurement and/or focus detection by means of image senser such as photo diode array (MOS image senser), CCD (charge coupled devices) consisting of a plural number of adjacently disposed respectively integrated fine light sensing elements whereby the image pattern of the object is scanned purely electrically in such a manner that the then obtained output of each light sensing element is converted into a digital value one after another for processing.