Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 19 - Current supply arrangements for telephone systems
Patents for H04M 19 - Current supply arrangements for telephone systems (7,475)
09/1992
09/01/1992US5144544 Power feed system for telephone and/or information technology terminals
08/1992
08/26/1992EP0499869A1 Circuitry for production of an alternating voltage
08/26/1992CN2114257U Telephone protector
08/25/1992US5142569 Apparatus for selectively enabling subscriber device to respond to ringing signal in dependence upon ringing cadence
08/25/1992US5142429 Overvoltage and overcurrent protective circuit with high earth balance
08/20/1992WO1992014332A2 An emergency call unit
08/19/1992EP0498997A2 Telephone apparatus with calling line identification
08/19/1992CN1063787A Communication central exchange
08/18/1992US5140630 Added main line apparatus
08/11/1992US5138658 Subscriber line interface circuit providing regulated current
08/05/1992CN1063392A Subscriber line interface constant current power supply installation
08/05/1992CN1063389A Distinctive ring system for cordless telephone
08/04/1992US5136630 Intrinsically safe telephone
08/04/1992CA1305924C Volume control circuit for use in portable telephone or the like
07/1992
07/21/1992US5133005 Line powered pay telephone with power management
07/15/1992EP0494709A2 Signal transmission system
07/15/1992EP0494525A2 Telephone apparatus with calling line identification
07/15/1992EP0494459A2 Distinctive ring system for a cordless telephone
07/14/1992US5131033 Sealing current generator for a telephone circuit
07/14/1992CA1305224C Electronic inductor
07/08/1992EP0493703A1 Communication system especially telephone communication system
07/07/1992US5128992 Hybrid circuit
07/07/1992US5128981 Radio communication system and a portable wireless terminal
07/01/1992CN2109029U Telecontrol power supply switch for telephone
06/1992
06/30/1992US5127004 Tone and announcement message code generator for a telephonic switching system and method
06/24/1992EP0491473A2 Control circuit for an electrical telephone accessory
06/19/1992CA2052854A1 Control circuit for an electrical telephone accessory
06/17/1992CN1062061A Telephone ringer circuit
06/17/1992CN1062060A Coupling device to be connected to dce for connection to public switched telphone network having local power supply circuit for allowing use of local telphone, dce and workstation including same
06/10/1992EP0489512A2 Telephone ringer circuit
06/10/1992EP0489215A1 Coupling device to be connected to a DCE for the connection to a public switched telephone network having a local power supply circuit for allowing the use of the local telephone, DCE and workstation including the same
06/06/1992CA2056132A1 Telephone ringer circuit
06/03/1992CN1016927B Digital composite tone alerting
05/1992
05/26/1992US5117449 Dual receiver apparatus for integrated paging and radiotelephone functions
05/12/1992US5113434 Battery boosted dial memory
05/12/1992US5113426 Ground fault detector
05/06/1992EP0483458A2 Power reduction technique for a time slot interchanger in the subscriber interface
04/1992
04/30/1992WO1992007414A1 Buck-boost converter circuit
04/29/1992EP0482466A1 Protection device for electrical and/or electronic telephone circuits, designed to limit the power dissipated within them
04/16/1992WO1992006523A1 Circuit protection device
04/15/1992EP0410978A4 Animated data display interleaving
04/08/1992CN2101353U Constant current supplying device for subscriber's line interface
04/07/1992US5103387 High voltage converter
04/07/1992CA1298678C Line interface circuit
03/1992
03/31/1992CA1298346C Communication line transient protection
03/24/1992US5099513 Integrated circuit for generating a melody and ring
03/24/1992US5099498 Method for suppressing quantization noises superimposed on a sinusoidal audible tone transmitted in a digital telecommunications exchange system
03/17/1992US5097503 Electronic subscriber line connection circuit
03/05/1992DE4027323A1 Call and feed voltage supply for PBX telephone appts. - feeds DC potential in rest and call states to subscriber line pair via different paths, under microprocessor control
03/04/1992EP0473465A1 Power saving arrangement and method in portable cellular telephone system
03/04/1992CN1059242A 线路接口电路 Line Interface Circuit
03/03/1992CA1296767C Floating battery feed circuit using multifilar transformer
02/1992
02/28/1992CA2043118A1 Power saving arrangement and method in portable cellular telephone system
02/26/1992EP0472289A2 Speakerphone state-controlled alerting arrangement
02/05/1992CN1058501A Power system for telephony system
02/04/1992US5086462 Terminal repeater having a function for repeating DC loop signal
02/04/1992US5086454 Direct connect modem deriving power from telephone line
02/04/1992US5086235 Power supply switchover device for electrical apparatus and teleaction terminal equipped therewith
01/1992
01/29/1992EP0468631A2 Power system for telephone systems with street cabinets connected to terminals and to an exchange
01/26/1992CA2045703A1 Power system for telephony systems
01/22/1992EP0467367A1 Subscriber line circuit for connection of a subscriber line for the transmission of analogue subscriber signals to a digital time division multiplex telephone exchange
01/22/1992EP0467212A2 Arrangement for the protection of a feed circuit of a subscriber line circuit of a telephone exchange against external overvoltages
01/22/1992EP0467071A2 Calling device for telecommunication terminals
01/20/1992CA2047450A1 Call alerting device for telecommunications terminals
01/15/1992EP0466601A1 Device for switching of an alternating interrupted calling signal on a telephone set connected to an exchange
01/15/1992EP0466000A2 Circuit arrangement for the attenuation of interfering voltages superimposed on the feed current for the subscriber terminals of a digital time-multiplexed communication system
01/09/1992DE4021335A1 Emergency mode signalling circuit for wideband communications - responds to switching of supply voltage from both lines to single wideband peripheral line
01/02/1992EP0463917A1 Digital device for conditional initialization
01/02/1992EP0463324A2 Circuit for communication terminals which switches a ring line from an active to a passive stade
12/1991
12/31/1991CA1293831C Apparatus for converting distinctive ring to selective ring in telephone lines
12/27/1991WO1992000643A1 Line interface circuit
12/27/1991EP0462649A2 Circuit for switching a telephone device between a voltage ringing generator and a power supply circuit
12/26/1991WO1991020141A1 Communications-transmission system
12/17/1991US5073922 Communication terminal apparatus
12/04/1991EP0458795A1 Circuit arrangement for a telephone subscriber station
12/03/1991US5070522 Combined signal and power distribution system
11/1991
11/26/1991US5068890 Combined signal and electrical power distribution system
11/26/1991CA1292588C Subscriber line interface circuit
11/21/1991EP0457397A1 Circuit for line current regulation in a telephone set
11/20/1991CN1056391A Overvoltage and overcurrent protective circuit with high earth balance
11/14/1991WO1991017623A1 Line interface circuit with active tip and ring feed means
11/13/1991EP0456624A1 Overvoltage and overcurrent protective circuit
11/13/1991EP0456129A2 Circuit for analogic terminal telephone sets connected to a digital line
11/13/1991EP0455894A1 Impedance synthesis multiple loop using filtering means
11/13/1991EP0455893A1 Telecommunication line circuit
11/13/1991CN1056212A 线路接口电路 Line Interface Circuit
11/12/1991CA2041957A1 Telecommunication line circuit
11/08/1991WO1991017598A1 An overvoltage and overcurrent protective circuit with high earth balance
11/08/1991CA2078696A1 Overvoltage and overcurrent protective circuit with high earth balance
11/06/1991EP0455335A1 Subscriber line interface circuit
11/06/1991EP0273922B1 Apparatus in a telecommunication system for supplying power to a telephone set
11/06/1991EP0269714B1 Method and apparatus for feeding power to a telephone line
11/05/1991US5063563 Communication terminal having means for controlling power transfer
11/05/1991CA1291836C Battery feed circuit
11/05/1991CA1291835C Ring trip circuit for subscriber telephone
10/1991
10/31/1991DE4013387A1 Telephone system operation - in which main phone is controlled by central controller and extensions can be added by 4-line
10/23/1991EP0452860A2 Facsimile apparatus comprising cordless telephone set
10/23/1991CN1055632A Self-powered base and remote telephone communication set
10/17/1991DE4031214C1 Telephone subscribers appts. circuitry with local battery supply - has repeater coil having split etc. windings so that current flows in opposed senses to prevent premagnetisation of core
10/16/1991EP0452286A1 Arrangement for reduced power supply to a subscriber line
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