Matches 151 - 200 out of 260 < 1 2 3 4 5 6 >
Match Document Document Title
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...
5027391 Call management system  
A call management system connected locally between a central office telephone company switching station (CO) and a conventional single telephone line having multiple extensions provides call paging...
5001748 Ringing signal generator  
A ringing signal generator includes a low power signal generator for generating a relatively low power signal representing a ringing signal, a bipolar pulse generator for generating a series of...
4995077 Card-like device having a microprocessor and speaker for communicating with a telephone line  
A card-like device having a microprocessor and a speaker to communicate with telephone line, the device also including a single switch which when depressed by a user first activates the device and...
4972466 Digital composite tone alerting  
Within a digital PBX system or the like, an appartaus permits provision of digital composite tone alerting particularly suitable for piezoelectric transducers with one arbitrarily selectable tone,...
4969186 Telephone message waiting system and apparatus  
A system transmits information over telephone lines using ring signals. The ring signals have bursts of selectable duration separated by selectable time intervals between bursts. A ring signal...
4964158 Power supply for telephone exchange  
A power supply (ringer power supply) for a telephone exchange comprising a first switching circuit for receiving and subjecting direct current to high frequency switching by means of a switching...
4962527 Series ringing signal generator  
A series ringing signal generator is disclosed which comprises a source of a user control signal. A programmable ringing signal generator is provided for generating an analog sine wave signal...
4942600 Communication apparatus for generating a call signal from a telephone set to a data terminal  
A call signal generating circuit includes a DC/DC converter, an ON/OFF control unit, including a control circuit and a phototransistor, for ON/OFF-controlling an output voltage from the DC/DC...
4926467 Line card with distributed signaling voltages  
A central office line card with distributed signaling voltages comprised of a plurality of subscriber line interface circuits connected to a common signal bus. Standard ringing signal is received...
4924511 Ring signal generator for generating ring signals of different frequencies and power levels in response to user selection  
A programmable ring signal generator includes a source of a user control signal. A controlled clock signal generator produces one of a set of respective clock signals responsive to the user control...
4908857 Isolated drive circuit  
The present invention provides a power drive circuit which is transformer isolated from the circuit developing the drive signals, but which does not lose its DC reference voltage. This technique...
4866587 Electronic ringing signal generator  
A switching power amplifier circuit has the functions of a power inverter and a switching amplifier embodied into one integral circuit. Two high frequency switching inverter circuits are connected...
4864604 Electronic wristwatch having dialing tone generator  
A wristwatch equipped with a dialing tone generator employs a low-frequency oscillator as a reference signal oscillator. The reference signal is frequency-divided into first and second...
4827503 Integrated ringing circuit and a ring trip circuit for the same  
A constant current circuit, including a constant current source which draws a current and a constant current source which sends a current, is connected to a two-wire subscriber line. A ringing...
4776008 Key-in sound-generating circuit  
A key-in sound-generating circuit comprises a keyboard including dial number keys and function keys, a DTMF signal generator coupled, at the output terminal, with a telephone network, a sound...
4769836 Dialing tone generator employing low frequency oscillator  
A dialing tone generator employs a low-frequency oscillator as a reference signal oscillator. The reference signal is frequency-divided into first and second frequency-divided signals. The first...
4737989 Ringing circuit  
The invention concerns an electronic ringing circuit for telephone systems. A capacitor is connected to the center tapping of a first coil inductively coupled to a transistor-controlled supply...
4734936 Ringing signal sending-out circuit  
A circuit for sending out a ringing signal of a high voltage and a low frequency to a telephone set through a telephone line repeatedly with a predetermined time interval. In order to omit use of a...
4727570 Waveform generators  
A stepwise approximation of a sinewave is generated by inputting different values representing different points on the waveform from a ROM (6) to a step duration counter (5). At the end of each...
4703500 Power amplifier  
A power amplifier includes negative and positive terminals for connection across a direct current supply, an input for receiving a reference signal and an output for supplying an amplified replica...
4651339 Multi-subscriber warning system  
A multi-subscriber warning system can, in instances where emergencies are impending, apply ringing current to the "ring" lines of one party systems, to the "ring" lines of "ring" two party systems,...
4631361 Programmable ring generator  
A ring generator capable of supplying a plurality of predeterminedly selected distinct voltages each having a predetermined high amplitude and a predetermined frequency to a telephone line...
4609782 Solid state signal insertion circuit and method for use in a telephony system or the like  
A solid state insertion circuit comprising an opto-coupler triac driver is activated by a solid state switch to insert a ringing signal onto a subscriber telephone path in order to ring, for...
4595797 Ringing signal generator for a subscriber telephone set  
A ringing signal generator for a subscriber telephone set comprising a switch switching the input signal, followed by a phase shifter and two symmetrical amplifiers having a very high output...
4584576 Ringing signal generator  
D.C.-fed ringing signal generator for a group of subscriber lines comprises a cascade arrangement of a digital signal generator controllable by a control signal to produce a signal corresponding...
4580011 Distributed processing telephone switching system  
A telephone switching system and method eliminates the need for high speed computers by employing a master controller having its own microprocessor to coordinate and control a tone controller, a...
4580016 Method and apparatus for checking the integrity of a communications channel in a voice store and forward system  
Method and apparatus for determining the integrity of a communications channel includes a first communications system connected to a communications channel with a receiving communications system...
4575585 Synchronous programmable signal generator and method  
A programmable signal generator and method for generating frequencies that are subharmonics of a rectified 60 hertz input signal. Opto-coupled triacs systematically switch and rectify the input...
4570034 Phone line ring signal detection circuit  
A ring detect circuit for detecting the ring signal on a telephone line and providing and electronic signal in response thereto, typically to initiate an automatic answer function. The circuit...
4533792 Circuit for switching between ring signal and message waiting signal without bell tap  
The invention relates to a circuit for switching between a ring signal and a message waiting signal in a telephone system, such as a PBX, without the occurrence of "bell tap". The instantaneous...
4514596 Telephone handsets  
A telephone subscriber subset including a transducer for generating audible signalling tone information in which the signalling tones are received at the input terminal as substantially sinusoidal...
4500844 Ringing signal generator employing delta-modulation power amplification techniques  
A ringing signal generator is disclosed in which a low-level reference ringing signal, generated by a reference waveform generator (101), is amplified by a delta-modulation power amplifier (106,...
4496800 Ringing generator testing arrangement for a digital telephone network  
A ringing generator testing arrangement for a digital telephone network is shown comprising a zero crossing detector connected to the ring lead of a line circuit under test. The zero crossing...
4472602 Telephone set with transducer/ringer  
There is disclosed a switch-hookless telephone set having a housing in the configuration of a handset housing, a cord, a plug and, within the housing, circuitry comprising: a ringing network...
4436960 Telephone ringing signal generator  
An AC-AC line current reversal technique is employed for generating a telephone ringing signal. Generation of the signal is accomplished by controllably activating one of two series full wave...
4431871 Solid state relay  
A solid state relay provides for a discontinuous transfer contact function. The solid state relay includes a first field effect transistor (FET) in a first switch, and second and third FETs in a...
4429188 Telephone call screener  
A telephone call screener discriminates between desired and undesired incoming telephone calls. Desired calls are signaled by use of a two-digit code known only to persons selected by the user. The...
4421953 Telephone tactile alert system  
A telephone user who cannot hear the telephone ringing is alerted, other than audibly, to the fact that the telephone must be answered. A radio transmitter at the telephone is driven by ringing...
4421952 Multi-frequency busy signal synthesizing circuitry  
Circuitry for synthesizing a busy or reorder tone comprised of a first tone having a frequency of 770 Hz and a second tone having a frequency of 1150 Hz is described. The inventive synthesizing...
4405833 Telephone call progress tone and answer identification circuit  
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...
4362908 Circuit arrangement for emitting ringing signals in a telephone system  
A circuit arrangement for emitting ringing signals to a subscriber station in response to a call signal electronically generated at a telephone exchange comprises a control unit which, in the...
4355206 Ringing control device  
A ringing control device for a group of subscriber lines served by a connection network, comprising a relay for each line, the connection network providing a ringing control signal and a timing...
4341928 Ringing signal supply  
A ringing signal supply, provided at a concentrator remote from a switching office, compares a fraction of its output with a low level reference ringing signal supplied from the switching office,...
4340785 Ringing signal supply  
A ringing signal supply, provided at a concentrator remote from a switching office, compares a fraction of its output with a low level reference ringing signal supplied from the switching office to...
4320258 Arrangement for requesting service for called telephone subscribers  
An improved ringing control circuit in a stored program telephone switching system which provides a called subscriber an interval or window of time after answering a call to send a request for...
4314102 Post office box monitoring system  
A system for detecting the presence of mail in a post office box. A post office box holder calls a telephone number which accesses a computer. The computer contains data representative of the...
4310733 Arrangement for applying signals to a telephone line  
Arrangement for applying signals to a two-wire telephone line, comprising two line control circuits each comprising a fed-back amplifier circuit. According to the invention the amplifier circuits...
4282410 Ringing signal generator  
A telephone ringing signal generator which sequentially produces a plurality of ringing signals each of a different frequency. Each of a plurality of tone ringers connected to the generator will...
4273964 Ring and tone plant  
A telephone ringing and tone generating circuit including circuitry for generating a plurality of tones, circuitry for generating a plurality of ringing currents and circuitry for generating a...
Matches 151 - 200 out of 260 < 1 2 3 4 5 6 >