H04M 19 - Current supply arrangements for telephone systems

Patents for H04M 19 - Current supply arrangements for telephone systems (7,475)
04/1989
04/11/1989	CA1252510A1 Electronic contacts and associated devices
04/06/1989	WO1989003147A1 Telephone accessory
04/05/1989	EP0310433A2 Radio telephone device
03/1989
03/29/1989	EP0309115A2 Line interface circuit
03/22/1989	EP0307781A1 Protection and remote powering system and device for an equipment connected by two transformers to a 4-wire transmission link
03/21/1989	US4815126 Telephone line switch
03/21/1989	CA1251587A1 Ringing signal reformatting circuit
03/14/1989	US4813072 Switching device for power supply to additional accessories for a telephone
03/14/1989	US4813066 Battery feed circuit for a telephone system
03/09/1989	DE3728230A1 Circuit for detecting an incoming ringing signal in a telephone set
03/07/1989	US4811391 Telephone set comprising a line voltage stabilizer having a DC supply point
02/1989
02/28/1989	US4809258 Circuit arrangement for the indication of loop closure during the ringing condition
02/28/1989	US4808905 Current-limiting circuit
02/15/1989	EP0303091A2 Circuit for a subscriber connecting circuit of a digital time division telecommunication network presented as a module
02/15/1989	EP0302957A1 Device for signalling a message in a telephone system
02/14/1989	US4805213 Ring detector
02/09/1989	WO1989001210A1 Telephone paging system
02/08/1989	CN1003272B Batlery-feed circuit for exchange
02/07/1989	US4803722 Circuit for remote supply of subscriber line terminals in a telecommunication system
02/07/1989	US4803721 DC control circuit
02/07/1989	US4803719 Method for powering telephone apparatus and telephone apparatus powered directly from the telephone line without external power
02/07/1989	US4803702 Reset and synchronization interface circuit
01/1989
01/26/1989	DE3723338A1 Visible scale of the sound volume at the telephone
01/24/1989	US4800589 Voltage regulator control circuit for a subscriber line interface circuit
01/24/1989	US4800586 Compensation circuit for use with an integrating amplifier
01/17/1989	US4799144 Multi-function communication board for expanding the versatility of a computer
01/11/1989	EP0298813A1 Public telephone apparatus with permanent connection
01/11/1989	CN1030334A Battery feed circuit
01/11/1989	CN1003069B Battery supply circuit for consumers' line
01/10/1989	US4797917 Monolithically integratable telephone circuit for supplying ringing signals to a subscriber's telephone line and for detecting an off the hook condition during ringing
01/10/1989	CA1248651A1 Telephone circuitry with power backup
12/1988
12/29/1988	WO1988010542A1 Ring trip circuit for subscriber telephone
12/28/1988	CN88103726A Subscriber line interface circuit and transformer therefor
12/21/1988	EP0295822A2 Subscriber line interface circuit and transformer therefor
12/21/1988	EP0295683A2 Protection circuit for battery feed circuit
12/21/1988	EP0295680A2 Battery feed circuit
12/21/1988	EP0295533A2 Subscriber connecting circuit
12/15/1988	DE3718008A1 Semiconductor circuit arrangement for full-wave rectification
12/14/1988	EP0294417A1 Apparatus in a loudspeaking telephone set for supplying power to an amplifier connected to the loudspeaker.
12/08/1988	DE3716141A1 Charge indicator for ISDN switching systems
12/07/1988	EP0294303A1 Circuit for a telephone set comprising a protection against voltage overloading
12/06/1988	US4790006 Method for electrically simulating a cradle switch and a hands free talking-loudspeaking key in a hands free talking-loudspeaking telephone station
12/06/1988	US4789999 Line circuit for coupling a subscriber set to a switching facility to provide a complex impedance match
12/06/1988	CA1246197A1 Switching system having tone trunk
11/1988
11/24/1988	DE3716140A1 Power connection relay (PCR) for telephone networks operated according to the ISDN system
11/24/1988	DE3716139A1 Secondary ringing unit
11/24/1988	DE3715552A1 Transmission circuit for communication signals - has transformer with output coil divided into two identical partial coils with capacitor in between
11/22/1988	CA1245383A1 Backup battery power supply for microprocessor based telephone
11/22/1988	CA1245382A1 Battery-feed circuit for exchange
11/22/1988	CA1245381A1 Line circuit for driving a ringer and a service indicating lamp in a telephone set
11/16/1988	CN88102480A Emergency d.c. power supply with emergency state being indicated by polarity reversal
11/15/1988	US4785406 Quad exchange power controller
11/03/1988	DE3713935A1 Circuit for ancillary telephone devices powered by the connection line
11/02/1988	EP0289387A1 Direct current power supply aided by an emergency condition indication by inversion
11/01/1988	US4782518 Apparatus for converting distinctive ring to selective ring in telephone lines
11/01/1988	CA1244166A1 Interswitch line circuit
10/1988
10/25/1988	US4780696 Multifilar transformer apparatus and winding method
10/20/1988	WO1988008234A1 Telephone subset circuit arrangement
10/19/1988	EP0286795A2 Circuit for the connection of ringing current in telecommunication exchanges, especially in telephone exchanges
10/19/1988	EP0286793A1 Circuitry for the overvoltage protection and the supply of a ringing current at a telecommunication connection line, especially a telephone exchange line
10/18/1988	US4779007 Uninterrupted power supply system
10/04/1988	US4776007 Solid state trunk circuit
10/04/1988	US4775975 Dial tone detection arrangement with a detection notification feature
09/1988
09/28/1988	EP0284571A2 A so-called switching voltage regulator for an interface circuit in a telephone subscriber line
09/21/1988	EP0283429A2 Circuitry for the signalisation of a call for a terminal apparatus connected to a digital telephone network
09/21/1988	EP0282578A1 Quad exchange power controller
09/21/1988	EP0282567A1 Low voltage and low power detector circuits
09/14/1988	EP0281578A1 Reset and synchronization interface circuit
09/14/1988	CN88100532A Volume control circuit for use in portable telephone or the like
09/13/1988	US4771449 Data station termination circuit
09/13/1988	CA1242039A1 Interface channel unit
09/08/1988	DE3706253A1 Circuit arrangement for telecommunications systems, in particular telephone switching systems, with DC voltage feed of switching devices via connection lines
09/01/1988	DE3705562A1 Telecommunication line unit
08/1988
08/31/1988	EP0280323A2 Portable cordless telephone set for outputting various discrimination sounds with simple circuit construction
08/30/1988	US4767980 Inductance multiplier circuit
08/30/1988	CA1241472A1 Battery feed circuit for a pair of subscriber lines
08/16/1988	US4764956 Active impedance line feed circuit
08/09/1988	US4763348 Controlled power supply for key telephone system
08/09/1988	CA1240432A1 Telephone subscriber line interface circuit with reduced power watchkee ping mode
08/03/1988	EP0277031A2 Volume control circuit for use in portable telephone or the like
08/03/1988	EP0276296A1 Current-limiting circuit.
08/02/1988	US4761812 Constant power telephone line circuit
08/02/1988	CA1240088A1 Solid state trunk circuit
08/02/1988	CA1240087A1 Limiting amplifier for common mode feedback in telephone line feed circuits
08/02/1988	CA1240085A1 Calling signal transmission apparatus
07/1988
07/28/1988	DE3701395A1 Method for operating a switched-mode regulator
07/27/1988	EP0275566A2 Method and device for reducing the energy requirement by a telephone set powered by the telephone line
07/27/1988	EP0275352A1 Circuit for the protection of electronic appliances against overloading
07/26/1988	US4760595 Subscriber line interface circuit having means for combining DC and AC feedback signals
07/12/1988	US4757528 Thermally coupled information transmission across electrical isolation boundaries
07/06/1988	CN87101278A Active impedance line feed circuit
07/05/1988	CA1238956A1 Switched capacitor coupled line receiver circuit
06/1988
06/29/1988	EP0272800A2 Active impedance line feed circuit
06/29/1988	CN87107404A Circuit arrangement for protecting electronic device to counteract excessive load
06/22/1988	EP0271946A2 Telecommunication device and circuits used therein
06/21/1988	US4752952 Subscriber circuit link interface for an automatic telephone exchange
06/16/1988	WO1988004502A1 Apparatus in a loudspeaking telephone set for supplying power to an amplifier connected to the loudspeaker
06/14/1988	US4751607 Communication line transient protection
06/08/1988	EP0269714A1 Method and apparatus for feeding power to a telephone line.
06/01/1988	EP0269579A2 A voltage regulator control circuit for a subscriber line interface circuit

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