Abstract: Automatic coin telephone station and central office facilities are disclosed for deriving data on the exact numbers and types of coins deposited during initial and overtime periods. Each station is equipped with nickel, dime and quarter binary counter memories and with flip-flop and logic gating control circuitry which is responsive to interrogate, coin collect and return signals received from the central office for sequentially interrogating the memories and frequency shift keying the stored information to the central office. A coin processor and memory, preference and connector, interrogate tone generator, and detectors are integrated into the central office switching system.

Abstract: An improved telephone toll restrictor utilizing both current and voltage sensors having substantially infinite input impedance during the on-hook condition. A timing circuit is provided to restrict calls a predetermined time after a digit is dialed but prior to central office timeout. Furthermore, a pulse generator provides a strobe pulse to a coincidence gate which also responds to a digit pulse counter, for avoiding restriction of a digit which should not be restricted.

Abstract: Automatic coin telephone station and central office systems have advanced recently to the point where facilities have been designed for accumulating at a centralized location data on the exact numbers and types of coins deposited in coin phones. This disclosure presents an arrangement for automatically processing a coin box removal signal (88) from a coin telephone station (1) to the central office (6) so that a determination can be made of the exact numbers and types of coins in the coin box at the time of its removal from the coin phone for collection. Each station is equipped with memories (16, 17, 18) for three different types of coins and a coin box removal memory (83). Flip-flop and logic gating control circuitry (26) is responsive to interrogate and coin collect signals received from a central office for sequentially interrogating the memories and frequency shift keying the stored information to the central office.

Abstract: This invention relates to an electronic system and a method for storing and distributing audio signals over existing communication lines. The system comprises a compressor for compressing in a predetermined manner the waveform amplitude of an input analog signal, thereby forming a compressed analog signal. The compressed analog signal is then converted into a digital signal by an analog to digital converter. A digital interface subsystem stores and retrieves selected ones of the digital signals for transmission over a communications line. At a remote end of the communications line the digital signal is converted back to its analog compressed signal representation by a digital to analog converter. The compressed analog signal is then expanded in a manner complimentary to the compressor operation, thus reconstructing the analog signal.

Abstract: An FM stereophonic receiver includes a system for producing a test signal having an audio frequency and a constant amplitude, permitting an easy setting of the input level of a tape-recorder which will record an FM program through the receiver. The system is so arranged that the oscillation frequency of a voltage-controlled oscillator involved in a phase-locked loop circuitry of a multiplex decoder in the receiver can be changed so as to make it possible to derive the test signal from a certain point in the circuitry. No separate audio signal generator is required for producing the test signal.

Abstract: A digital echo attenuation circuit for a two-wire-four-wire local telephone circuit in which each digital sample of the transmit and receive signals is compared directly and the results used to augment an accumulator. Once the accumulator reaches a certain threshold level, its output controls a digital pad to attenuate the receive signal and thereby prevent severe distortion and near singing effects.

Abstract: An alarm and audit system for use with loop start telephones and with either semi-post-pay or pre-pay operations, and installed as office equipment for tabulating and storing information concerning collections from coin operated pay telephones, so as to ensure optimum collection and as a perceptive alarm against burglaries; utilizing counter means activated by coin tone bursts transmitted over a pair of normal telephone lines; in semi-post-pay phones the tone burst information being conducted directly to memory means; in pre-pay phones the tone burst information being held in abeyance to be released for tabulation in the memory means by a positive voltage applied when collecting coins, or dropped from said abeyance means by a negative voltage applied when returning coins. The tabulation is accumulative in one of two memory means selectively called upon by computer means to produce information for distribution to those concerned with servicing the said pay telephones.

Abstract: A moisture protective housing for a sound transducer located inside the face mask of a diver which face mask is vented to a breathing apparatus, such as a scuba tank with regulator, to maintain the air breathed by the diver at substantially the same pressure as the water surrounding the diver. The housing includes a deformable portion having pin prick perforations or pores therethrough to make that portion porous when formed. The number of perforations or pores, as well as their size, are selected such that the porous portion becomes permeable to air and/or water only if the pressure differential across it exceeds a preselected value.

Abstract: A digital repeater for the regeneration of partial-response signals having improved noise immunity which basically comprises an equalizer followed by a regenerator. A band limiting filter disposed between the equalizer and regenerator transforms the partial-response signal to a modified form having the same or fewer levels and concurrently reduces the total power of the noise interference. A second filter disposed after the regenerator and having an inverse transfer function replicates the partial-response signal at its output so that the repeater appears transparent to the transmission line.

Abstract: PCM words transmitted on a number of incoming and outgoing links during time slots according to a time division multiplex system are space interchanged by utilizing a circulating shift register wherein at the beginning of their allotted time slots, each of incoming PCM words is registered each in an associated shift register stage. The circulating shift register is stepped by a clock pulse so fast that each PCM word is stepped through all shift register stages during the respective time slot. Control words, each associated with one of the time slots and with one of the outgoing links, determine during which clock pulse an outgoing link is connected to the output of its associated shift register stage. A buffer memory arranged between the circulating shift register and the outgoing links re-establishes the correct time division multiplex system for the outgoing PCM words.

Abstract: A loop extender is used in conjunction with a pair of telephone lines extending from a telephone central office to a subscriber location in order to insert a booster DC potential on the telephone lines in such a manner as to aid the flow of DC current produced on the telephone lines by a telephone central office battery. A control circuit has one input terminal coupled to one of the telephone lines and a reference terminal, another input terminal coupled to the other telephone line and the reference terminal, and an output terminal coupled to a relay. Whenever the input terminals are supplied with a specified potential from the telephone lines, an output from the output terminal maintains the relay in a nonenergized condition so that contacts controlled by the relay couple a DC booster power supply in series relationship with one of the telephone lines.

Abstract: A control circuitry for a radio telephone having a transmitter, a receiver, a cradle and a handset. The handset includes a first computer having a stored program control therein, a first memory, a telephone number display and a pushbutton pad. The cradle includes a second computer having a stored program control therein, a second memory, a plurality of control switches and radio telephone status indicators. A dialed number is entered into the handset memory from the pushbutton pad, under control of the handset computer. Then during a telephone call, the entered number is transferred from the handset computer to the cradle computer and transmitted by the cradle computer. Frequently called numbers can be stored in the handset memory or the cradle memory and later, can be readily recalled and transmitted. The last dialed number can be automatically retransmitted in a subsequent call.

Abstract: An improved cutover block enabling a plurality of telephone circuits to be conveniently transferred from one switching location to another switching location. The cutover operation is performed manually by disconnecting a printed circuit board carried by the cutover block, rotating the board about 180.degree. on its own axis, and reconnecting it to the cutover block to result in reconnecting the circuit to another location. For convenience, the cutover block is made to the same dimensions as a standard telephone connector block, so that it may be mounted conveniently on a frame adjacent an existing connector block with which it is associated.

Abstract: Telephone command apparatus responsive to ringing current on a telephone line includes a decoder responsive to upper and lower frequency components of two-tone signals and an access and lockout device responsive to decoded signals representative of a correct sequence of two-tone signals for terminating the incoming telephone line and enabling a plurality of relays for actuation selectively in response to other two-tone signals received over the telephone line to initiate and complete one or more operations at the called location. Until the correct sequence of two-tone signals is received, the command apparatus has no effect on the telephone line to which it is connected and the line functions in the normal way. Transmittal of an incorrect series of two-tone signals to the access and lockout device disables the command apparatus and renders it incapable of responding to incoming signals for a predetermined period of time.

Abstract: A receiver circuit for a multi-frequency telephone dialling system has means for validating a received tone by making successive measurements of the tone period and validating the tone when m of n successive measurements lie within a single one of a number of given ranges and when, subsequently, l(< m) of n successive measurements of the tone also lie within that single range.

Abstract: A domed member is positioned on the center of a telephone dial. Opposite each finger hole is a raised identifying character such as a Braille number corresponding to the number of the finger hole or a raised Arabic number which can be readily identified by a blind person. A flat on the edge of the member is oriented with the finger stop to assist in locating the member relative to the dial. Preferably the member is removable so that it may be installed and removed while traveling. For such purpose, the base of the member may have pressure-sensitive adhesive, or the member may be hollow and contain a suction cup, or the member may have clips for attachment.

Abstract: A central station system in which the central station is normally connected to one or more remotely located bridging points by a dedicated communication path, each bridging point having a plurality of output ports to which one or more remote station devices are connected. In response to address signals generated by the central station, abridging point connects an identified output port to the dedicated communication path to allow communication between the associated remote stations and the central station. All other output ports are electrically isolated from the dedicated communication path. In the event of failure of the dedicated communication path, apparatus is provided for establishing an alternate communication path through the commercial telephone network. The system is highly immune to tampering and other forms of failure because of automatic decision-making capabilities of the bridging point and other features of the apparatus.

Abstract: A digital linear interface system to interface between the output of a tape deck and a separate data input for each of n channels of data input. Each channel of the digital linear interface system consists of a high Q bandpass filter, a rectifier, a peak detector, and a phase locked loop demodulator. A light emitting diode connected between the rectifier and the phase locked loop demodulator lights when the bandpass filter is tuned to the center frequency. The system separates n linear sine waves having data stored on a separate sine wave for each channel.

Abstract: Circuitry for interconnecting a radio transceiver to a telephone line is disclosed. The circuitry provides controlled access to the telephone system lines from remote radio transceivers by way of a base transmitter-receiver unit which is connected through an impedance matching network to the telephone line. A carrier operated relay responsive to the base receiver unit controls access to the telephone line by means of a time delay relay whereby signals received by the base station are connected to the telephone line. Audio signals originating in the telephone line are detected by a voice operated relay which activates the base unit transmitter to transmit such audio signals for two way communication with the remote radio unit on a single frequency channel.

Abstract: An elongated manually manipulable housing contains a photocell at one end for sensing energy levels in the visible frequency spectrum causing said photocell to correspondingly change in electrical conductivity. A portable power source in the housing is coupled to the photocell to provide an electrical signal corresponding to the change in the photocell conductivity. A comparator circuit in the housing compares that signal with an adjustable reference signal to provide an output signal upon a predetermined ratio between the compared signals. A multivibrator circuit in said housing is coupled to said comparator circuit and to a vibration-generating means which produces signals preferably in the audible range, so that upon the occurrence of an output signal, a user discernible, either audible or tactile, vibratory signal is generated.