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)
09/1982
09/15/1982EP0060006A1 Loop detector with small sensibility for longitudinal voltages
09/14/1982US4349703 Programmable ring signal generator
09/14/1982CA1131818A1 Current limited subscriber line feed circuit
09/14/1982CA1131564A1 Digital signal mixing apparatus
09/08/1982EP0059469A1 System for forwarding along a telephone connection the identities of the subscribers involved in that connection
09/07/1982CA1131333A1 Method of controlling call traffic in a communication switching system
09/07/1982CA1131332A1 Communication system tracking arrangement
08/1982
08/31/1982CA1130899A1 Gain controller for a teleconferencing bridge
08/31/1982CA1130898A1 Method for testing communication paths
08/24/1982CA1130407A1 Automatic telecommunication exchange system
08/18/1982EP0057854A2 Automatic telephone answering machine
08/18/1982EP0057852A2 Automatic telephone answering machine for private automatic branch exchanges
08/17/1982US4345324 Process and system for error detection in a computer-controlled telephone exchange
08/17/1982US4345273 Broad band switching system
08/03/1982CA1129056A1 Method of and an apparatus for a radiotelephone communications system
08/03/1982CA1129055A1 Method and system for reducing conference bridge oscillations
08/03/1982CA1129001A1 Location of contact faults on electrically conductive cables
07/1982
07/28/1982EP0056545A1 Installation for the localization of interruptions and short circuits in a two-wire line
07/27/1982US4342111 Digital bridging apparatus for telephone conferencing system
07/27/1982US4341929 Memory accessing system
07/27/1982CA1128628A1 Low power consumption relay switching circuit for use in conjunction with a line test trunk interfacing to a test desk
07/20/1982US4340960 Time division switching system
07/20/1982US4340913 Tri-level digital recording
07/20/1982US4340788 Method of and system for measuring electrical characteristics of circuit elements included in time-sharing telecommunication network
07/20/1982US4340779 Interpreter intercommunication and public address system
07/20/1982CA1128222A1 Lineman's hand test set
07/14/1982EP0055977A1 Portable instrument for measuring the attenuation of a subscriber's telephone line
07/13/1982US4339818 Digital multiplexer with increased channel capacity
07/13/1982US4339816 Conferencing apparatus and methods for a frequency division multiplex communications system
07/08/1982WO1982002307A1 On-hook/off-hook detector circuit
07/08/1982WO1982002287A1 Voltage controlled transient protection unit
07/06/1982US4338494 Telephone call inventorying and sequencing system and method
06/1982
06/30/1982EP0054902A2 Method and apparatus for answering telephone calls automatically
06/29/1982US4337378 On-hook/off-hook detector circuit
06/29/1982US4337376 Communications system and network
06/29/1982CA1126840A1 Data storage and retrieval structure for a message storage system
06/24/1982WO1982002133A1 A method and apparatus for transferring the same information to a plurality of receivers
06/24/1982WO1982002132A1 A device for the referral/transfer of calls in telephone exchanges
06/23/1982EP0054120A1 Service integrated transmission system
06/22/1982US4336424 Circuit arrangement for monitoring operating conditions of direct current devices
06/15/1982CA1125936A1 Toll restrictor
06/08/1982US4334129 Telephone digital office cutover system
06/01/1982US4332985 Automatic calling methods and apparatus
05/1982
05/25/1982US4331950 Broad band switching network
05/25/1982US4331913 Precision negative impedance circuit with calibration
05/25/1982US4331843 Apparatus for controlling and indicating the integrity of the connection of telephone subscribers to a switching system
05/18/1982US4330886 Automatic telephone exchange system for both speech signals and data transfer
05/18/1982US4330688 System for statistical supervision of trunk-dialed long-distance telephone calls
05/13/1982WO1982001635A1 Improvements in or relating to line interface circuits
05/12/1982EP0051495A1 Ring scheduling apparatus for a digital multiplexed telecommunication system
05/12/1982EP0051494A1 Automatic maintenance and self-test system for a digital multiplexed telecommunication system
05/12/1982EP0051446A1 Improvements in or relating to line interface circuits
05/04/1982US4328396 Total service telephone answering system
04/1982
04/27/1982US4327256 Telephone system
04/27/1982US4327253 Circuit arrangement for consecutively monitoring operating conditions of direct current devices
04/27/1982US4327251 Automatic telephone directory message system
04/20/1982US4326103 Coin telephone monitor circuit
04/14/1982EP0049471A1 Subscriber line testing apparatus
04/14/1982EP0049287A1 Portable telephone line test set
04/13/1982USRE30903 Computer controlled telephone answering system
04/13/1982US4325139 Circuit for combining delta modulated signals
04/13/1982CA1121925A1 Method and apparatus for detecting irregular telephone calls
04/13/1982CA1121891A1 Toll fraud detector
04/07/1982EP0049213A1 Circuit for common controlled telephone exchanges, especially private telephone exchanges and special private telephone exchanges, with identification means assigned to the keys of operator positions
04/07/1982EP0049212A1 Circuit for common controlled telephone exchanges, especially private telephone exchanges and special private telephone exchanges, with digitally controlled operator positions
04/07/1982EP0049211A1 Circuit for common controlled telephone exchanges, especially private telephone exchanges and special private telephone exchanges, with at least one operator position and an information handling device attached to this position
04/07/1982EP0049210A1 Circuit for common controlled telephone exchanges, especially private telephone exchanges and special private telephone exchanges, with means to indicate if a subscriber set and/or operator position is operational
04/07/1982EP0048940A1 Subscriber connecting circuit
04/07/1982EP0048868A1 Communications system, especially telephone system
04/07/1982EP0048740A1 Automatic calling methods and apparatus
04/06/1982US4323738 Portable telephone line test set
03/1982
03/30/1982CA1121076A1 High voltage switch and capacitive drive
03/24/1982EP0047782A1 Memory accessing system
03/23/1982US4321430 Subscriber's connecting network comprising a symmetrical power amplifier for feeding a subscriber's line
03/23/1982CA1120570A1 Time-slot interchange with protection switching
03/17/1982EP0047524A1 Communications system, particularly telephone system, for the connection of mobile subscriber terminal equipments
03/16/1982US4320497 Method for testing communication paths
03/16/1982US4320338 Methods of and apparatus for determining the capacitance of a transmission line by integrating line currents
03/16/1982US4320260 Circuit arrangement for determining the connection condition of a subscriber line in a telecommunications network
03/16/1982US4320257 Compensation of transmission losses in a telephone system
03/16/1982US4320256 Verbally interactive telephone interrogation system with selectible variable decision tree
03/16/1982CA1120144A1 Digital conference
03/10/1982EP0047046A1 Arrangement for exchanging signals between separated circuit arrangements
03/09/1982US4319092 Current detection circuit arrangement for an automatic telephone exchange
03/09/1982US4319090 Method of determining existing service capabilities of telephone exchange equipment
03/04/1982WO1982000743A1 System for the testing of telephone switching systems
03/03/1982EP0046623A2 Installation for the recording of oral messages directed to different addressees, and for the reproduction of these messages during the recall of an addressee
03/02/1982US4317967 Fault isolation device
03/02/1982US4317961 Telephone-conferencing apparatus and method
03/02/1982US4317960 Telephone-conferencing and inquiry-handling apparatus and method
03/02/1982CA1119330A1 Subscriber's circuit
03/02/1982CA1119329A1 Conference circuit
03/02/1982CA1119282A1 Microprocessor control complex
02/1982
02/24/1982EP0046224A1 Method for common-controlled telecommunication exchanges, particularly for telephone private branch exchanges with operator positions working differentially
02/23/1982US4317007 Telephone-conferencing method and apparatus with monitor-only access
02/23/1982CA1118925A1 Audio teleconferencing
02/23/1982CA1118922A1 Universal signal generator for generating telephone system high level signals
02/23/1982CA1118875A1 Identifier for manual switchboards with conference facility
02/17/1982EP0045941A1 Dialling method for establishing a connection in a telephone switching system with digital speech transmission
02/16/1982US4316059 Gain controller for a teleconferencing bridge
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