Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 3 - Automatic or semi-automatic exchanges
Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881)
08/1989
08/08/1989US4856050 Telephone message retrieval system with improved message processor and retrieval console including auto-disabling playback switch
08/08/1989US4855941 Process for compression of a data set
08/02/1989EP0326366A2 Improvements in telephone technician's terminals
08/02/1989EP0325794A2 ISDN system with a subscriber line multiplexer for establishing different D-channel links
08/01/1989US4853952 Method and apparatus for visual indication of stored voice signals
07/1989
07/26/1989EP0325327A1 Method of asynchronous duplex data communication between two stations relating to specific services to be performed through a common communication channel, and stations for carrying out the method
07/26/1989CN1004916B Signal transmitting system of master-control telephone set
07/25/1989US4852156 Private telephone system using a personal code number to access the telephone nearest to the code number holder
07/25/1989US4852154 Pay-per-view CATV system
07/25/1989US4852151 Modem with call waiting
07/25/1989US4852149 Automated call filter
07/25/1989US4852145 Telephone subscriber loop test system
07/25/1989US4852144 Traffic generator analog
07/25/1989US4851937 Apparatus for securing access to a communications recorder
07/20/1989DE3806262C1 Circuit arrangement for monitoring the state of switching points in a digital space-division switching network
07/18/1989US4850012 Automated access facilities for use with key telephone systems
07/18/1989US4850007 Telephone toll service with advertising
07/18/1989US4849971 Carrier telephone service analysis system
07/18/1989US4849966 Announcement system
07/18/1989US4849846 Telephone protection circuit
07/13/1989DE3743959A1 Method for checking operational functions of a computer-controlled communication switching system
07/11/1989US4847896 Monolithically integratable telephone circuit for supplying ringing signals to a subscriber's telephone line and for detecting an off the hook condition during ringing
07/11/1989US4847890 Anonymous interactive telephone system
07/11/1989US4847885 System for measuring and automatically compensating for the distorsions of a connection between a telephone apparatus and a central voice processing unit
07/11/1989US4847829 Video conferencing network
07/11/1989US4847806 Method and apparatus for giving identity to, and selecting one of a plurality of function units
07/11/1989CA1257419A1 Network event identifiers
07/06/1989EP0313562A4 Telephone on-hold device.
07/06/1989DE3743401A1 Circuit arrangement for telecommunication switching systems, particularly telephone switching systems, with facilities for acquiring switching events arriving in a sequence
07/05/1989CN1033725A Changeover system of dispatching telephone
07/04/1989US4845756 Apparatus for through-connecting audio signals
07/04/1989US4845739 Telephonic-interface statistical analysis system
07/04/1989US4845737 Method for measuring line parameters of subscriber lines of a telecommunication system
07/04/1989US4845736 Cross-connect switch and method for providing test access thereto
07/04/1989US4845499 Method for generating PCM logarithmic values from linear values
07/04/1989US4845497 Conference circuit for a digital communication system
07/04/1989CA1257026A1 Message taking and retrieval system
06/1989
06/29/1989WO1989006083A1 Data transmission system
06/29/1989WO1989006078A1 Enhanced dedicated teleconferencing system
06/29/1989WO1989006077A1 Remotely commanded telephone switch enhancing system
06/29/1989WO1989006076A1 Automated access facilities for use with key telephone systems
06/28/1989EP0322075A2 Switching network and controller for a switching system
06/28/1989EP0321540A1 Apparatus for achieving a controllable line termination impedance
06/28/1989EP0321498A1 Directory assistance call processing and non-supervisory signal monitoring arrangements.
06/27/1989US4843620 Hand-held telephone line signaling test instrument
06/27/1989CA1256612A1 Remote testing system for electrical circuits
06/27/1989CA1256611A1 Method of and circuit arrangement for evaluating the output signals of current flow detectors in telecommunication facilities
06/22/1989DE3820315C1 Method for two-way interchange of data between a communications switching system and a staff time recording system
06/21/1989EP0321084A2 Teleconferencing system including paperless facsimile means
06/20/1989US4841566 Hold and dial accessory for telephone instrument
06/20/1989US4841560 Direct access test unit for central office
06/20/1989US4841559 Telephone network interface tester
06/20/1989US4840448 Optical fiber transmission apparatus, in particular for submarine use
06/20/1989CA1256185A1 Interface circuit for transmitting command codes to an attendant console
06/20/1989CA1256184A1 Interface circuit for transmitting keycodes to a centrex
06/20/1989CA1256036A1 Microphone actuation control system suitable for teleconference systems
06/15/1989WO1989005552A1 Routing of network traffic
06/14/1989EP0320426A1 Coordinated transfer of voice and information through a digital switch
06/13/1989US4839919 Telephone and demodulator
06/13/1989US4839916 Telephone toll integrity checking system
06/13/1989US4839643 Broadband signal switching equipment
06/07/1989EP0319282A2 A voice mail system with improved detection and cancellation
06/07/1989CN1033341A Private automatic branch exchange
06/07/1989CN1033340A Method and circuit for controlling audio conference between at least three participants
06/06/1989US4837818 Telecommunication line circuit
06/06/1989US4837816 Communication system using switching apparatus
06/06/1989US4837811 Telephone technician's terminals
06/06/1989US4837810 Telephone switch center with control of individual devices
06/06/1989US4837808 Circuit connecting a voice-controlled device to a telephone station and line
06/06/1989US4837804 Telephone answering voiceprint discriminating and switching apparatus
06/06/1989US4837799 Telephone line communications control system
06/06/1989US4837798 Communication system having unified messaging
06/06/1989US4837797 Electronic message unit and methods using same
06/06/1989CA1255409A1 Subscriber line circuit having an improved offhook supervision circuit
06/01/1989WO1989005080A1 Communication device
06/01/1989WO1989005078A1 Optical communications network
06/01/1989WO1989005077A1 Optical communications network
06/01/1989WO1989005070A1 Optical communications network
06/01/1989WO1989005069A1 Optical communications network
06/01/1989WO1989004845A1 Nitrogen-containing esters of carboxy-containing interpolymers
05/1989
05/31/1989EP0318428A1 Communication device
05/31/1989EP0318335A1 Fault location in optical communications networks
05/31/1989EP0318333A1 Stations for a digital communications network
05/31/1989EP0318332A1 Synchronisation of digital communications network
05/31/1989EP0318331A1 Scrambling in a digital communications network
05/31/1989EP0203147B1 Automatic redialing arrangement for multi-line telephone station sets
05/30/1989US4835773 Duplicated equipment
05/30/1989US4835767 Additive PCM speaker circuit for a time shared conference arrangement
05/30/1989US4835766 Monitoring system capable of monitoring a sequence of digital signals flowing through a subscriber line
05/30/1989US4834551 Call holding alert system
05/30/1989CA1254980A1 Customer programmable real-time system
05/24/1989EP0317463A1 Conference arrangement circuit for a plurality of participants in telecommunication systems
05/24/1989EP0317059A2 Private automatic branch exchanges
05/23/1989CA1254638A1 Reconfigurable high-speed integrated local network
05/18/1989WO1989004573A1 Call appearance reservation arrangement
05/16/1989US4831651 Intermediate amplifier for use in two-wire connections of a dial telephone network and method for the gain control of said amplifier
05/16/1989US4831618 Additive PCM speaker circuit for a time shared ISDN conference arrangement
05/11/1989DE3830037A1 Test instrument for testing continuity of subscriber lines
05/11/1989DE3736897A1 Circuit arrangement for telecommunication switching systems, particularly telephone switching systems, with facilities for detecting individual switching events arriving in a sequence
05/10/1989CN1032874A Automated matrix for communication line connection
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