Abstract: Call coverage problems are solved in a telephone communication system by arranging the system on a station orientation basis so that any call directed to a station on any line appearance at that station will be covered by a single button on any one of a number of other coverage station sets. Any other station may also have its calls directed to that same coverage station set and, if desired, to the same call coverage button on the covering set. By separating ringing signals and flashing signals and by handling each on a station basis, it is possible to allow both ringing and visual signals of the call if covered by one station, whereas if call coverage is handled by another station it can be arranged so that only visual signals will be provided.

Abstract: A subscriber's circuit for a four-wire-system local switch is provided with a two-wire/four-wire hybrid circuit that includes a two-wire/four-wire converter circuit. Connected between the converter circuit and a time-division switch section is an incoming circuit that amplifies an incoming voice current, supplies a DC current to a subscriber's telephone set, and generates a subscriber's line signal of large amplitude, such as a bell and a howler signal, by repeatedly reversing the polarity of the DC current. An alarm signal is produced by stepwise changing the duration and the frequency of the repetitive polarity reversal in response to digital command signals supplied from the time-division switch section.

Abstract: A modulated RF carrier signal distributing arrangement, utilizing existing line circuits, is disclosed for providing entertainment signals to key telephone lines in the active noncommunicating (hold) state. The disclosed system utilizes an existing option connector on the line circuit for connection of a music receiver circuit. A centrally located transmitter circuit frequency modulates its own RF carrier with an externally supplied music signal and is wired to the existing common dc power to distribute the modulated RF signals to the receiver via the option connector on each line circuit. The receiver circuitry demodulates the RF signal and couples the resulting music signal directly across the hold bridge leads of the associated line.

Abstract: A priority mixer control for a multi-microphone audio system comprises a threshold signal generator that develops a scanning D.C. threshold signal starting at a maximum level for a time T1 and then decreasing in amplitude as a function of time. Each microphone channel is provided with a control channel including a comparator that compares the microphone signal, as an A.C. signal, with the threshold signal, and that switches the microphone channel to "on" condition when the microphone signal exceeds the threshold; all of the control channels are coupled to a threshold signal restoration means that drives the threshold signal back to its maximum level each time an audio channel is switched "on". An audio channel that has been switched "on" remains "on" for a time T2 substantially longer than the time T1. The number of channels currently in "on" condition is continuously monitored and the output gain is reduced whenever two or more channels are in "on" condition.

Abstract: A telephone control console including visual indicator means, data input means, audio frequency input and output means, microprocessor means, data transmission and reception means wherein said microprocessor means controls at least some of said visual indicator means in accordance with data received by said data reception means and in accordance with data input through said data input means and also controls the transmission of data by said data transmission means in accordance with instructions from said data input means and wherein said audio frequency input and output means include an input and output for an operator's telephone.

Abstract: A busy signal connecting set is immediately released by the disengagement of a connecting station participating in an existing connection, and a state of interception is established for the subscriber circuit of the subscriber station which has not yet released. The subscriber circuit is connected with a house set for the purpose of connecting the busy signal by way of time switching equipment which is activated after a delay time in response to production of the state of interception.

Abstract: A controller at a monitor location generates interrogate signals which are transmitted over a telephone line to a transmitting unit associated with a plurality of underground gasoline storage tanks. The transmitting unit responds to the interrogate signals to selectively couple pressure sensing lines to a pressure sensing transducer. Each line extends into a different one of the storage tanks and provides a pressure which is proportional to the depth of the liquid in the corresponding tank. As each line is coupled to the transducer in sequence, the transducer provides an output voltage corresponding to the sensed pressure. The output voltage controls a transmitter of the transmitting unit which generates an audio signal related in frequency to the sensed pressure, and the frequency signal is transmitted over the telephone line to the controller which detects and decodes the frequency signal and controls a display unit to provide a visual display of the liquid level in the selected tank.

Abstract: The disclosed signalling apparatus provides a different identifying signal in response to a ringing signal for one or more telephone station sets connected by a common line to a centralized switching, control and signalling machine. The different identifying signals are generated in response to the number and timing of ringing signals applied to the line. If a first ring is sensed and within a predetermined first time a second ring is sensed, a first identifying signal is initiated. If a first ring is sensed and after the predetermined first time but before a predetermined second time a second ring is sensed, a second identifying signal is initiated. If a first ring is sensed, but a second ring is not sensed before the predetermined second time, the signalling apparatus is reset to initial conditions.

Abstract: A switching arrangement for a telecommunication switching system having test and seizing circuits is disclosed in which test switching means for bounce-free contact operation require a seizing current rise delayed by switching means in the seizing circuit. The improvement comprises a transistor for establishing the seizing current, a testing resistor disposed in series with the transistor and an RC network associated with the transistor. The potential across a control electrode of the transistor which is determined by the charging voltage of said associated RC network defines a control current. The potential renders the transistor increasingly conductive to current in accordance with a charging process setting in at the start of a test and seizing operation.

Abstract: A microphone support assembly for use by a harmonica player or the like includes an adjustable size ring adapted to surround a finger of the wearer and a cylindrical, open ended case affixed to the ring at an outer edge thereof. A microphone element is adapted to be inserted within the case and the microphone wires attach to an electrical connector supported on a strap supported on the user's wrist. The connector allows attachment to external amplifier circuitry.

Abstract: A frequency division multiplexing system is disclosed having a plurality of individual modulators which modulate respective modulating signals onto respective carrier frequencies. The carrier frequencies are selected to have a frequency separation so that when modulated signals are combined, significant parts thereof do not overlap in frequency. The combined modulated signals are filtered by comb filters which suppress portions of the frequency spectra intermediate the significant portions.

Abstract: A ringing control apparatus comprises a bidirectional switching circuit connected in series to a ringing source, which generates an alternating current of a large amplitude, for delivering to a called subscriber the AC signal as an interrupted ringing signal, a phase detector circuit in the form of a zero level detector for detecting the phase of the AC signal generated from the ringing source, and a control circuit for generating a signal for turning on and off the switching circuit in synchronism with the output signal of the phase detector circuit. The delivery of the ringing to the called subscriber is started at a point of time when the ringing voltage comes to a zero level and is stopped at a point of time when the ringing current comes to a zero level, thereby to prevent generation of a surge voltage.

Abstract: A dial signal receiver for receiving and decoding telephone digit signals in either dual-tone multifrequency (DTMF) or rotary dial pulse form is disclosed. DTMF digits are accepted, if, simultaneously, both the high and low frequency components, derived from a band-split filter, repetitively pass a short term check; and each component passes a long term check once. The short term checks comprise repetitively measuring the period of two consecutive cycles of each component of the input signal. The long term check comprises measuring the period of a number of cycles of each component of the input signal. The number of cycles for each component is dependent on the nominal frequency determined by the short term check of that component. At the end of a cycle related period, a "window" is opened for a time interval related to the expected frequency, as determined by the short term check. If a short term check pulse occurs during the open window period, the related component is accpeted as valid.

Abstract: In a carrier subscriber terminal, a voltage regulator converts the line voltage to a relatively uniform operating voltage for driving a power converter that charges a local battery. The control circuit for the converter comprises a programmable unijunction transistor (PUT) Q1 having a gate and anode connected to intermediate points of associated pairs of resistors R1-R2 and R3-R4 that are electrically connected across the line, and having a cathode connected through a first capacitor C1 and associated discharge path to one side of the line. A Zener diode D5 is resistively connected across the line to establish a reference voltage which is connected through a first diode D1 to the PUT anode, through second and third diodes D2 and D3 to the PUT gate, and through only the second diode D2 to a second capacitor C2 of the regulator.

Abstract: A method is disclosed of preferentially accessing a group of positions (12 in FIG. 1) for a first type of call over a second type of call in a telephone system (FIG. 1) in which the positions (12) are served by a uniform or automatic call distributing office (1). In accordance with one aspect of the invention, selected ones of the positions (12) are marked unavailable for serving calls after the completion of a call of the second type. Thereafter the selected positions are accessed by overriding the unavailable state for a prescribed number of calls of the first type and, at the completion of the prescribed number of calls, the selected positions are again marked available for serving calls. In accordance with a second aspect of the invention, responsive to a first prescribed traffic delay condition in placing calls of the first type to the positions, ones of the positions are successively marked unavailable for serving calls as each completes a call. This occurs as long as the traffic delay state exists.

Abstract: In a PCM time multiplex telecommunications network the digital signal input of the coder/decoder of each subscriber station has an individually controllable receiving memory connected to the input of the coder/decoder, and the digital signal output of the respective coder/decoder has an individually controllable transmitting memory connected thereto. The control of the signal receipt and transmission by the coder/decoder takes place at different points in time than the receipt of PCM signals by the receiving memory, and the transmission of PCM signals by the transmitting memory.

Abstract: A multi-frequency signal receiver for use in tone signalling circuits is disclosed. The receiver includes a plurality of channel band pass filters having mutually independent pass bands, each of which receives the input signal. Threshold detectors are connected to the outputs of the channel bandpass filters as is a variable threshold circuit. The variable threshold circuit includes a peak hold circuit and an attenuator for generating a threshold value for the detectors. A rectifier and integrator circuit rectifies an output which is weighted compared with the output of the peak hold circuit to produce a timing signal. The timing signal is used to gate the output of the detectors.

Abstract: A removable hook for attachment to a microphone hangup button has a loop portion permitting a microphone to be conveniently hung from a suitable projection. Two parallel, spaced apart rails extending from the loop have inwardly extending portions for slideably engaging the grooves in the undercut portion of the hangup button. A resilient arm member extends over and holds the microphone hangup button in place.

Abstract: The use of plural cell sizes in cellular high capacity mobile telecommunications systems is facilitated by providing dual service availability in an essentially geographically continuous large-cell grid and an overlaid and essentially geographically discontinuous small-cell grid. When using certain frequency channel set assignment plans, large-cell antenna sites employ their ordinary channel set assignments whether or not a small-cell antenna site is also present. When a large-cell site is operated in the vicinity of a co-channel small-cell site, the respective channels of the large-cell site are operated in a large-cell mode or a small-cell mode as required to cooperate with the overlaid small-cell site. When using frequency channel set assignment plans requiring departures from ordinary large-cell channel assignments, the departures are similarly effected on the large-cell site channels that are operated in the small-cell mode.

Abstract: An echo cancelling system, in which a pseudo-echo is provided by producing an impulse response of an echo path, reversed in phase and then applied to a subtractor of the echo path to cancel an echo. A low level reference signal, such as random noise or an artificial random signal, is continuously applied to the echo path and successively delayed by a sampling period to obtain a plurality of delayed reference signals, which are multplied by the output of the subtactor to obtain a plurality of multiplied outputs. The multiplied outputs are integrated by integrators and then amplified by high gain amplifiers to be employed for producing the psuedo-echo. As a result of such construction of the adaptive control loop, the convergence time for cancellation is effectively improved.