| Patents for H04M 19 - Current supply arrangements for telephone systems (7,475) |
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| 07/22/1993 | DE4139610A1 Adjusting subscriber terminal signal transmission parameters - taking place after loop closure recognition and maintaining until loop end closure |
| 07/21/1993 | EP0551530A1 Amplifier biasing circuit suitable for a ring-trip detection system |
| 07/20/1993 | US5230018 Communication system for activating an optical display in a communication terminal of a communication switching station |
| 07/20/1993 | CA1320605C Terminating circuit in a battery feed circuit of an electronic exchange system |
| 07/14/1993 | EP0550554A1 Circuit protection device. |
| 07/14/1993 | EP0276296B1 Current-limiting circuit |
| 07/13/1993 | US5228081 Ringing signal control circuit for an enhanced subscriber line interface |
| 07/06/1993 | US5226078 Adjustable integrated/discrete-element line current controller in a telephone set |
| 06/29/1993 | US5224154 Line powered DCA including dual programmed microcontrollers |
| 06/29/1993 | US5224152 Power saving arrangement and method in portable cellular telephone system |
| 06/24/1993 | WO1993012621A1 Intercom system |
| 06/24/1993 | WO1993012569A1 Electronic device with dual purpose regulator |
| 06/24/1993 | DE4142007A1 Data and speech transmission system using 4-wire telephone cable - has respective line wire pairs for transmission of speech and data signal in opposite directions between speech points and exchange |
| 06/23/1993 | EP0547301A2 Low-loss power feeding circuit for telephone apparatus |
| 06/15/1993 | US5220597 Dialing apparatus for power failure extension telephone set of key telephone system |
| 06/09/1993 | EP0545066A1 Telephone answering apparatus including power failure protection |
| 06/09/1993 | DE4140153A1 Telephone subscriber's appts. circuitry with call signal generating circuit - has cradle switch contact disconnecting rectifier bridge from call tone circuit and supplying speech circuit |
| 06/08/1993 | US5218634 Ringer assembly |
| 06/08/1993 | US5218285 Electronic device with dual purpose regulator |
| 06/03/1993 | WO1993011624A1 Telephone ringing signal generator |
| 06/03/1993 | DE4139608A1 Supply voltage setting system for communications subscriber circuit - uses detected loop circuit resistance upon initial connection of subscriber circuit to 2=wire subscriber line |
| 06/03/1993 | CA2101842A1 Telephone ringing signal generator |
| 06/01/1993 | US5216710 Liquid crystal display driver and power supply |
| 06/01/1993 | US5216708 Calling signal controller |
| 06/01/1993 | US5216707 Circuit for firing paystation coin relay using power derived from telephone line tip/ring voltage |
| 06/01/1993 | US5216704 Method for remote power fail detection and maintaining continuous operation for data and voice devices operating over local loops |
| 05/25/1993 | US5214692 Bypass for telephone switching system |
| 05/11/1993 | US5210788 Telephone instrument and distribution system |
| 05/04/1993 | US5208723 Solid state electronic protector with pressure release |
| 04/14/1993 | EP0536970A2 Incoming call alert system for cellular telephones without wired connection thereto |
| 04/14/1993 | EP0536183A1 Line interface circuit. |
| 04/13/1993 | US5202917 Telephone calling method and telephone apparatus |
| 04/06/1993 | US5201068 Radio telecommunications apparatus |
| 04/01/1993 | DE4132146A1 Controlling subscriber terminals to establish connection - using central control for conversion of pulse into message for answering machine when calling subscriber hangs up |
| 03/31/1993 | EP0533755A1 Communications-transmission system. |
| 03/16/1993 | US5195128 Communication system, particularly a telephone communication system |
| 03/10/1993 | EP0530722A2 Method and circuit arrangement for suppression of the first ring of telephone sets connected to additional equipment |
| 03/09/1993 | US5193212 Circuit for saving battery for use in a radio paging receiver and method thereof |
| 03/04/1993 | DE4226834A1 ISDN network termination with U interface component and S bus - has intermediary point for subscriber's appts. supplied by exchange battery or local accumulator if mains supply fails |
| 03/04/1993 | CA2077160A1 Subscriber line interface circuit with differential voltage sensing and compensation |
| 03/03/1993 | EP0530089A2 Communication apparatus having function of generating calling signal |
| 03/03/1993 | EP0529633A2 DC termination circuit for 2B1Q line-coded basic rate ISDN |
| 03/02/1993 | US5191507 Polarity inverting circuit |
| 03/01/1993 | CA2076720A1 Dc termination circuit for 2b1q isdn basic rate physical layer line code protocol |
| 02/23/1993 | US5189697 For supplying energizing direct current from a power source |
| 02/18/1993 | DE4126352A1 Volume adjusting circuit for ringing transducer of telephone - connects different outputs of controller to earth via different resistances depending on position of push button indicating desired volume |
| 02/10/1993 | EP0294417B1 Apparatus in a loudspeaking telephone set for supplying power to an amplifier connected to the loudspeaker |
| 02/09/1993 | US5185738 Fiberoptic telephone systems |
| 02/03/1993 | EP0525298A1 Portable radiotelephone |
| 02/02/1993 | CA1313432C Speaker drive arrangement for loudspeaker telephone |
| 01/27/1993 | CN1068460A Current limited subscriber interface circuit |
| 01/21/1993 | WO1993001676A1 Ringing trip judging circuit |
| 01/21/1993 | WO1993001665A1 Personal communication system providing supplemental information mode |
| 01/21/1993 | DE4123763A1 Vol. adjustment for telephone terminals with loudspeaker - has analog gate incorporated in signal path leading to electroacoustic transducer |
| 01/21/1993 | CA2112594A1 Personal communication system providing supplemental information mode |
| 01/20/1993 | CN1068229A Telephone circuit assembly with hook-off detector circuit |
| 01/19/1993 | US5181240 Data circuit-terminating equipment with power source device |
| 01/19/1993 | US5181023 Terminal unit of a mobile communication system |
| 01/19/1993 | US5180987 DC-to-AC symmetrical sine wave generator |
| 01/19/1993 | CA1312971C Low power control apparatus for a coin operated telephone |
| 01/19/1993 | CA1312970C Method and apparatus for electronic payphone open switch interval management |
| 01/12/1993 | US5179586 Line interface circuit |
| 01/07/1993 | WO1993000763A1 Telephone marketing system |
| 01/07/1993 | DE4221306A1 Sensor control circuit for electronic routing of telephone signals - comprises in=line coil which couples electrical signal with magnetic sensor e.g. Hall element to provide electrical isolation |
| 01/07/1993 | DE4121196A1 Vol. setting control for telephone subscriber's appts. - uses call tone generator providing different tone signal during setting procedure |
| 12/30/1992 | EP0520171A1 Subscriber line interface circuit with an off-hook detection circuit |
| 12/30/1992 | EP0520156A2 Current limited subscriber interface circuit |
| 12/29/1992 | US5175764 Enhanced high voltage line interface circuit |
| 12/24/1992 | DE4120077A1 Ringing current for hands-free telephone station - includes separate polarity protection for amplifier and control microprocessor drawing upon isolated DC supply |
| 12/16/1992 | CN1067144A Method and apparatus for electronic payphone open switch interval management |
| 12/15/1992 | US5172412 Subscriber circuit capable of suppressing in-phase induced noise |
| 12/15/1992 | US5172409 Precision FET control loop |
| 12/15/1992 | US5172408 Speakerphone state-controlled alerting arrangement |
| 12/15/1992 | US5172092 Selective call receiver having audible and tactile alerts |
| 12/09/1992 | EP0517321A2 Telecommunication system comprising a supply circuit for a telecommunication line, and a supply circuit for a telecommunication line suitable for use in the telecommunication system |
| 11/25/1992 | EP0515102A2 Automatic loss control circuit in a digital loop transmission system |
| 11/25/1992 | EP0514695A2 Telephone set with ring tone inhibit circuit |
| 11/10/1992 | US5163090 Over-current verifier circuit for an enhanced subscriber line interface |
| 11/04/1992 | EP0511920A1 Variable level driver circuit for periodic excitation of a capacitive load |
| 10/29/1992 | WO1992019062A1 Current limited circuit for subscriber interface |
| 10/29/1992 | DE4113758A1 Circuit for transistorised microprocessor controlled telephone station - has control current switchable via microprocessor coupled by opto-coupler for speech circuit switch=on |
| 10/27/1992 | US5159627 Adaptive ringer for telephone terminal |
| 10/20/1992 | US5157721 Control circuit for an electrical telephone accessory |
| 10/20/1992 | US5157711 Telephone terminal device |
| 10/13/1992 | US5155764 Telephone set with on-hook line seizure |
| 10/13/1992 | CA1308825C Terminal repeater having a function for repeating dc loop signal |
| 10/13/1992 | CA1308824C Party line converter |
| 10/07/1992 | EP0507482A2 Telephone ring generator with automatic volume control according to the ambient noise level |
| 10/01/1992 | WO1992014332A3 An emergency call unit |
| 09/26/1992 | WO1993019516A1 Dc/dc/ac power supply |
| 09/23/1992 | EP0504716A2 Method for the activation of an optical indicator in a communication apparatus connected to a switching exchange |
| 09/23/1992 | EP0504658A2 Method for the activation of an optical indicator in an analogic communication terminal connected to a communication equipment |
| 09/16/1992 | EP0503528A2 Subscriber line interface circuit for ISDN and POTS applications, including echo canal cirenitry |
| 09/16/1992 | CN1018323B Low power control apparatus for coin operated telephone |
| 09/15/1992 | US5148475 Reduced contact resistance on a SLIC |
| 09/09/1992 | EP0502617A2 Portable radio telephone |
| 09/08/1992 | US5146490 Passive telephone line monitoring system |
| 09/08/1992 | CA1307315C Telephone protection circuit |
| 09/03/1992 | DE4105462A1 Generating calling AC voltage in telephone subscriber circuit - producing DC voltage with amplitude control by pulses of different pulse-interval ratio |
| 09/02/1992 | CN1064179A Circuit arrangement for generating ac voltage |