Abstract: A telephone ring detector circuit is provided which finds particular utility in telephone answering systems. The detector circuit responds only to ring signals on the telephone line to activate the system, and it is unresponsive to dialing pulses, or other signals, that may be present on the telephone line. The detector circuit of the invention distinguishes the ring signals from the other signals on the telephone line by counting the number of pulses present on the telephone line for the various signals and providing a ring detect output only when the number of pulses is in excess, for example, of the pulses which form the trains of the dialing signal.

Abstract: A rotary-type control for a headphone earpiece has an indexing dial which is loosely keyed to the control shaft of a potentiometer and extends partially through an opening in the cover of the earpiece to permit the wearer of the earpiece to manually control the potentiometer. The loosely keyed indexing dial is centered in the opening in the cover of the earpiece by the cooperative action of a journal bearing on the underside of the cover, a raised hub-like projection on the top of the indexing dial which is received and journaled in the bearing and a spring which exerts an upward force on the bottom of the dial keeping the hub-like projection journaled in the bearing so that the dial is level and centered in the opening in the cover.

Abstract: An improved microphone structure having a ball screen enclosing the transducer. The microphone body or handle has an annular shoulder at its upper end to provide an upstanding externally threaded projection. The lower part of the ball screen has an opening to receive the upstanding handle projection, the peripheral portion of the screen at the opening being turned inwardly and adapted to be secured to an internally threaded base ring. The base ring is threaded on the handle projection to secure the ball screen in place.

Abstract: An apparatus for interconnecting a telephone line and a calculator having a printer and display means, wherein input detecting means are provided for recognizing dialing pulses and charge pulses on the telephone line, and output driving means are provided for acting upon the calculator only at points thereof corresponding to input keys and switches thereof which usually serve also to introduce values and give operating orders to the calculator, this output driving means being arranged first to control the printer for causing it to print telephone numbers in accordance with the number of dialing pulses detected by the input detecting means, then to control an addition process in the calculator for causing its display to indicate the charges successively incurred during a call, and finally to control the printer for causing it to print the total charges incurred during this call after the line has been restored.

Abstract: Circuitry for integrity verification is provided to prevent a calling party from unknowingly remaining connected to a faulty trunk connection between an automatic switching office and an operator-assisted office. New circuit arrangements are added to the outgoing trunk circuit of the automatic office and to the line circuit of the operator-assisted office. At the outgoing trunk circuit, binary memory elements and associated circuitry are employed to delay the completion of the normally executed cross-office continuity check at the automatic office, thereby delaying release of common control equipment at that office. During the delay interval, interoffice integrity check signals are exchanged between the outgoing trunk circuit and the line circuit. Circuitry is added to the line circuit for the generation of a wink signal in response to a seizure signal from the outgoing trunk circuit. This wink signal is received at the trunk circuit as a timed off-hook signal followed by a steady on-hook signal.

Abstract: In a two-wire bidirectional telephone transmission line, a power converter and a directional threshold detector form in combination an impedance transparent bilateral voice-signal controller which can supply stable voice-switched gain to a dominant signal originating from either direction and a simultaneous, equal loss to any signals propagating from the other direction without separating the respective signals.

Abstract: A telephone signaling and paging system is disclosed. The signaling and paging system senses the presence of a telephone message when recorded by a telephone answering system and automatically dials a preselected number to provide an alerting signal or page. Upon receipt of the alerting signal or page, the recipient, by dialing the answering unit number, can receive the recorded message and hence can be quickly alerted to the contents of the recorded message. The system includes a provision for repeated dialing of the preselected number by the system until contact is made to assure prompt message alerting, and also includes a provision for precluding signaling or paging should no message be recorded by the telephone answering unit. In addition, the system includes means wereby the alerting signal or page may be manually activated for alerting or paging purposes.

Abstract: A headset including a pair of earpieces and a head strap extending from one earpiece to the other earpiece, and with the head strap including end portions and the earpieces each including a cavity and with each end portion extending into the cavity in the earpiece and with the ends of the end portions enclosed within the earpieces, and with the end portions of the head strap slideable within the cavities in the earpieces for providing adjustment of the headset and including stop members to limit the travel of the end portions, and with wires extending through the head strap from one portion to the other end portion and into the earpieces and with the wires fully contained within the head strap and the earpieces.

Abstract: A sound frequency reproduction system and apparatus has a chair for a human. A transducer is vibrated by a sound signal of appropriate frequency. The vibrating shaft of the transducer is directly fitted to the framework of the chair. The sound signal is provided to an acoustic device, including a speaker, located near the chair.

Abstract: A hearing protector for providing protection from high volume sound waves. The protector is a headset including earmuffs, at least one of which contains a microphone for receiving sound waves and a speaker for transmitting sound waves to the ear of a person wearing the headset. The signal to the speaker is filtered to reduce the amplitude of any frequency components outside of a predetermined audio frequency range. A CMOS integrated circuit is connected as an active voltage sensitive variable resistance element of a control circuit for automatically limiting the volume of the sound waves provided by the speaker, in response to variations in the level of the sound received within the predetermined audio frequency range.

Abstract: A function control code sequence of signals, each comprising a pair of audio frequency tones, is transmitted from a control location to a remote station selector. Each input signal is applied to a tone decoder element which separates the two tones through a filter, amplifier, detector network to produce a pair of logic signals representing the tones received. The sequential pairs of logic signals are applied to a code selector which converts the 2 of 7 format into a 1 of 12 digital code sequence equivalent to the original function control code selected at the control location. This digital sequence is applied through a programmable cross bar connector matrix to a sequence detector responsive only to a predetermined input sequence. The matrix is programmed to produce this predetermined sequence and actuate the sequence detector only when an assigned function code is received.

Abstract: Centralized toll restriction for private branch exchanges (PBXs) is performed by providing first and second memory addresses in the number translator of a central office switching system. The first and second addresses are matched with restricted telephone calls and unrestricted telephone calls, respectively. Those telephone lines of each PBX which are to be restricted are marked in a convenient manner, such as with tip to ground marking, while those telephone lines not restricted are left unmarked. Outgoing trunks between the PBXs and the central office switching system are temporarily marked with an unbalance upon going off-hook on a restricted telephone line, in order to transmit restriction indication to the central office switching system.

Abstract: A conventional telephone pay station is adapted for coin-free restricted dialing of a preselected number of digits by employing a two-coil latching relay operating a switch for shunting outgoing calls, one coil being operated after a predetermined time delay responsive to detection of an offhook condition to open the switch, and the second coil being operated responsive to the detection of dialing by the calling party of a number of digits greater than the preselected number to close the switch. Anti-fraud circuits are provided to interrupt tone generator operation after a predesignated time delay following each digit, and to interrupt service after each hook switch operation.

Abstract: A dual-tone multiple frequency signal generator is provided for use with telecommunications systems, data transfer systems and other applications. The tone encoding system utilizes MOS/LSI integrated circuitry on a single chip powered directly by telephone line voltages. An electronic keyboard circuit provides synchronized pulses to decode single-pole, single-throw keyboard switches by row and column. A crystal-controlled oscillator generates a reference frequency which is divided according to the row and column of an activated keyboard switch to obtain two pulse signals having frequencies representative of the activated switch. The outputs of the divider circuitry are fed to programmed logic array which generates two digitally coded signals each representing a sinusoidal waveform. A digital-to-analog ladder network converts the digitally coded signals to continuous sine waves, and an operational amplifier combines the sinusoidal waveforms to provide a dual-tone output.

Abstract: A stereo speaker system removably mountable on the back of a seat includes two speaker assembly enclosures pivotally mounted on a spacer bar to maintain the speakers at a desired separation and orientation and a strap for securing the enclosures and spacer bar to the back of the seat. Each enclosure includes a chamber substantially occupied by a speaker assembly and a duct portion for directing the sound.

Abstract: A key telephone adapter unit providing interconnection between a key telephone instrument having a line selector unit with a plurality of lines and a corresponding plurality of line status indicators and an electronic telephone switching system in which audio frequency voice information signals and supervisorial serial data signals are interfaced to individual telepone handsets by first and second conductor pairs.The adapter unit responds to a serial data polling command received from the switching system over the data pair by converting signals representative of the status of each line of the associated key telephone instrument to serial data signals for transfer to the switching system over the data pair; and responds to other serial data commands received from the switching system over the data pair by generating command signals for directing operation of the line status indicators, e.g. the status lamps, the bell and the buzzer.

Abstract: A digital tone decoder includes means for generating a timing signal, zero crossing counter means for generating a decode signal after a predetermined number of zero crossings in response to an incoming time domain signal and for generating a reset signal at a predetermined time after the decode signal is sent to reset said zero crossing counter means to zero, and decoder means coupled to said zero crossing counter and to said timing means for generating an output signal at one of a plurality of output terminals corresponding to the frequency of the incoming signal upon receipt of the decode signal from said zero crossing counter means, said decoder means being reset to an initial state upon receipt of the reset signal.

Abstract: The system includes a holder for a microphone, a mounting structure for mounting the holder from a dashboard in the drivers compartment of a vehicle, and mechanisms for operating the microphone while operating the vehicle. The operating mechanisms include a lever arm pivotally mounted on the holder with a plate portion of the lever arm located adjacent to and spring biased outwardly from a control button extending from one side of the microphone situated in the holder, a trigger which is mountable on a control arm extending from a steering column of a vehicle and a cable connected between the trigger and the lever arm. Typically the vehicle control arm is one used by a handicapped person having limited use of his legs and includes acceleration and brake controls. The system permits a vehicle operator to operate the microphone without removing his hands from the steering wheel and control arm of the vehicle while operating the vehicle.

Abstract: Conference conversations are provided among selected groups of stations in a communications system. Each of a plurality of stations generates speaker signals and conference control signals and responds to a designated listener address signal in order to receive selected elements of a listener output signal from a central processor. A programmable list processor responds to the conference control signals and generates memory address signals and control signals. A random access memory sequentially stores and periodically updates samples of the digital speaker signals and generates a series of listener output pulses in response to the memory address signals. An accumulator additively stores selected groups of listener output pulses and upon receiving an appropriate control signal generates a listener output signal. A listener address circuit also responds to the control signal and generates the listener address signal.

Abstract: The invention involves the use of a plurality of incoherent noise generators distributed, in one embodiment, along ceilings in open-plan and partitioned office spaces and the like, to diffuse masking sound energy through acoustical tile and other false ceiling structures while tailoring the same for speech privacy results, by providing a uniform, delocalized and incoherent masking sound space.