Matches 101 - 150 out of 259 < 1 2 3 4 5 6 >
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5655003 Wireless terminal having digital radio processing with automatic communication system selection capability  
A wireless terminal utilizing digital radio processing utilizes stored program control to allow the wireless terminal to operate in a plurality of disposed wireless communication systems. In...
5649005 PC with telephony exchange function  
A key telephone system (KTS) or a telephone private branch exchange (PBX) card is integrated into a personal computer to provide telephone system features. The telephone card includes a call...
5638440 Protection circuit for telephone systems  
A power-cross detection circuit includes a zero crossing detection circuit for detecting a first zero crossing of the current from a first positive half-cycle to a first negative half-cycle, a...
5638435 Impulse signal convertor  
An impulse convertor for converting a received telephone impulse dialing signal into a restored dialing signal has a limiter-amplifier, a signal detector, an output formatter, and a controller. The...
5602911 System and method for eliminating bell tap on analog telephones  
A system and method for modifying a composite Ring AC/Message Waiting (RAC/MW) signal to prevent bell tap on analog telephones. The composite RAC/MW signal comprises AC signals and DC signal...
5600713 On-board ring signal generator  
A ring generator circuit that produces a ring output for a plurality of telephones simultaneously. The ring generator circuit includes a switch that receives an oscillating signal in response to an...
5592529 Telephone inadvertent off-hook condition detector  
An inadvertent-off-hook-condition detecting apparatus for use with a telephone connected to a telephone system is described. The telephone has a hookswitch which connects the voice network of the...
5583933 Method and apparatus for the secure communication of data  
An auto-dialer suitable for use as a smart card capable of being acoustically coupled to a telephone and being reprogrammed in response to acoustic signals. The programming and other features of...
5563943 ISDN interface unit with separate ring generator  
An ISDN interface unit interconnects a data processing unit, an ISDN, and an analog telephone and includes a ring sound controller for supplying a control signal to designate a generation of a ring...
5555301 Power supply apparatus and method for energizing telephone alerting mechanisms and circuitry  
In a digital data communications device for use in an ISDN environment, a power supply apparatus and method are provided for energizing telephone danger circuitry or other alerting mechanisms....
5535273 Circuitry for superimposing small, low energy signals and large, essentially higher energy signals  
A circuitry is disclosed for superimposing small, low energy (2) and large substantially higher energy (3) signals, in particular for transmitting speech signals with a remote supply direct signal...
5530743 Telephone exchange apparatus and tone sending method in telephone exchange apparatus  
In a telephone exchange apparatus for performing exchange processing by a memory time switch, first tone signals are generated, and second tone signals are generated by sequentially...
5526418 Ringer circuit  
A ringer circuit comprising a rectifier circuit, a voltage regulator and a ringer generation circuit is provided. The rectifier circuit generates a DC voltage signal at an output terminal and has...
5509068 Electronic ring monitoring device for telecommunications line  
An electronic ring monitoring device is disclosed that includes telecommunications interface circuitry, ring detection circuitry, isolation circuitry, and output driver circuitry. The...
5495530 Low power emergency telephone mode  
A cordless telephone that may be fully powered by AC main power lines and only partially powered by telephone lines includes structure for producing dual tones, structure for producing dual-tone...
5491746 Unique ringing on a prime telephone  
A telephone switching system is comprised of a main controller, switching circuits controlled by the main controller, a peripheral controller for controlling the seizing of subscriber lines for...
5490054 Ringing generator and method for converting DC to AC having continuously adjustable amplitude  
A ringing generator and a method for converting a DC input voltage signal from a DC source to an AC output voltage and supplying this output voltage to a variable load, The output signal has a...
5461670 Telephone subscriber system incorporating a drive interface for a telephone line switch at a different reference potential  
A telephone subscriber system comprising a speech circuit and a ring circuit adapted to be integrated monolithically to a semiconductor material substrate and being coupled to a telephone...
5442698 Ringing generator for telephones  
A ringing generator includes a binary signal source generating a waveform with eight degrees of freedom controlled to suppress or cancel certain harmonics to produce a binary low frequency signal...
5436964 Programmable call progress tones for a switching system  
In accordance with an embodiment of the invention, a method of establishing call progress tones for a switching system having a generic signal generating apparatus, comprising the steps of...
5426695 Ringing signal control circuit capable of suppressing surge voltage  
In a ringing signal control circuit for controlling supply of a ringing signal from a ringing signal generator to a subscriber's line in response to a call signal destined thereto, a switching...
5406623 Method and apparatus for ringing telephone stations  
A telephone ringing arrangement where a non-sinusoidal ringing voltage waveform is used that has significantly longer intervals during which the waveform is near zero as compared to a sinusoidal...
5404582 Aural annunciator circuit for a receiver  
An aural annunciator circuit for a radio receiver and a radio transceiver incorporating such. The annunciator circuit is operative to generate an aural signal when a signal is transmitted to the...
5402480 Call signal generating circuit  
A call signal generating circuit includes a step-up transformer having a primary winding and secondary windings and a first switching circuit coupled between the primary winding of the step-up...
5384807 ADPCM transcoder with integral tone generation and method therefor  
An ADPCM transcoder (60) includes an integral tone generator (65) which inserts a linear tone signal, such as a conventional DTMF tone signal, into either the transmit or receive data stream, or...
5363443 Differing frequency sine wave generation from a look-up table  
Sine waves are generated by a port circuit processor of a telephone switching office by accessing a look-up table stored in a memory associated with the port circuit processor. Entries in the...
5353342 Adaptive multitone signaling method  
An inband tone signaling method results in improvements in talk-off and talk-down performance without sacrificing important human factors considerations. The inband tone signal transmitter has a...
5343510 Wireless telephone  
A wireless telephone has a function of monitor-outputting an operation sound as an operation key is pressed. The wireless telephone can be operated in one of three modes, namely, none push-tone...
5337356 Ringing circuit for use in portable telephone set  
A portable telephone set having a ringing circuit for producing different ringing tones depending upon the use mode of the portable telephone set, a portable mode or a mobile mode. The ringing...
5323456 Digitally controlled ringer signal generation  
A method and apparatus, of producing an alarm or ringing signal by providing a first pulse signal having a predetermined pulse width to define an alarm or ringing signal amplitude, and modulating...
5323455 Ringer circuit, particularly for a telephone set  
The ringer comprises a loudspeaker receiving signals from an amplifier, the amplifier having both a power supply input connected to a ringer line providing a ringer signal via a chopper power...
5321596 DC/DC/AC power supply for a subscriber interphase unit  
A DC to DC switch mode power supply for a service subscriber interface unit of a fiber optic network includes a source of DC primary power, a main DC to DC switched mode power supply connected to...
5307407 20 Hz ring generator using high frequency PWM control  
A low frequency high voltage AC power for a telephone system is provided by a ring signal generator, which produces a ring signal from a DC power supply using a pair of switches controlled by pulse...
5295185 Ringing signal generation circuit with protection against overvoltage  
A ringing signal generation circuit contains a direct current power source, a transformer, a control transistor, a rectifying and smoothing circuit, an invertor circuit, and an invertor controlling...
5260996 Current limited electronic ringing generator  
An electronic ringing generator circuit with provision for power efficient current limiting and preservation of sinusoidal or near sinusoidal output waveform under overload conditions. A pulsewidth...
5255310 Method of approximately matching an input character string with a key word and vocally outputting data  
A method for approximately matching a DTMF input character string with a key word and for vocally outputting information in response to the input character string. A telephone apparatus is provided...
5247573 Telecommunications system comprising a circuit arrangement for at least one subscriber station  
A subscriber line control circuit for controlling a reversing switch to couple a subscriber station either to an AC signalling voltage generator or to a DC line voltage supply, depending on whether...
5208852 Sound generation circuit  
A sound generation circuit for producing a dual tone which includes memory circuitry for storing data for controlling production of the dual tone, selection circuitry for selecting data stored in...
5182767 Electronic telephone device  
The device includes an acoustic transmitter (10), a tone generator (12), a memory (14) containing an identification code (N) and a service key (C), and an electronic circuit (16). A digital message...
5163084 Voice information service system and method utilizing approximately matched input character string and key word  
A voice information system utilizing approximately matched input character string and key word and a method for the approximate matching thereof is disclosed. A telephone apparatus is provided to...
5157720 Dialler chip mode signal  
A telephone circuit arrangement allows the use of a (high voltage) dialler chip (3) without a mode select output in a low voltage telephone. A filter (R1,C1) derives control signals from the DTMF...
5140630 Added main line apparatus  
An added main line system is disclosed with particular utility in connection with equipment for providing the services of two telephone lines on a single conductor pair. The ring generator of the...
5128991 Dialing confirmation tone output apparatus  
A dialing confirmation tone (DCT) output apparatus including a variable attenuator connected between a DCT generator and an adder adding a received voice signal and a dialing confirmation tone. The...
5127004 Tone and announcement message code generator for a telephonic switching system and method  
A tone and announcement PCM code generator (10) outputs to selected multiple channels of a TDM telephonic switching system (12) selected tones and voice announcements stored in a message memory...
5119418 Telephone system with several terminals on a single line  
In a telephone system, several telephone terminals are connected to a single telephone line including several telephone interface circuits (6, 7, 8), each interface circuit being energized by...
5091934 Tone modification system for telephone system with clock  
A telephone system with a clock includes a circuit which produces a first tone indicating a connection of a transmission line is on hold or that a preset time has arrived, and a different time...
5056135 Method of automatic equalized distribution of ring loads for telephone exchange system  
A method of automatically and equally distributing the ring load for an exchange system. The subscribers are grouped so that at any one time the subscribers of one group only is supplied with the...
5048076 Control apparatus for an automated telephone attendant  
Automated telephone attendant equipment involving a technique for connecting an incoming call on an external line to one out of a plurality of telephone devices. Each telephone device is connected...
5034977 Phase accumulation dual tone multiple frequency generator  
A method and apparatus for generating dual tone multiple frequency signals employing a low frequency quartz oscillator, wherein a phase accumulation dual tone multiple frequency generator is...
5031212 Dialer circuit  
A dialer circuit comprising a microcomputer for controlling the dialing of a telephone. This dialer circuit is capable of storing a telephone number and transmitting a signal concerning this...
Matches 101 - 150 out of 259 < 1 2 3 4 5 6 >