Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 9 - Arrangements for interconnection not involving centralised switching
Patents for H04M 9 - Arrangements for interconnection not involving centralised switching (8,105)
11/1982
11/09/1982CA1135425A1 Signal multiplexing circuit
10/1982
10/26/1982CA1134523A1 Telephone group listening systems
10/26/1982CA1134522A1 Voice switch for hands free communication apparatus
10/06/1982EP0061812A1 Disposition of acoustic transducers and use of this disposition in a hands-free telephone apparatus
10/06/1982EP0061524A1 Method for the bidirectional transmission of binary data signals on a signal line closed on both sides by a transformer
09/1982
09/28/1982US4352180 Digital time-division multiplex telecommunication system
09/21/1982US4351049 Circuit arrangement for user stations in a communications network
09/14/1982CA1131817A1 Computer controlled key telephone station set
09/08/1982EP0059543A1 Parallel operation of telephone equipment on a digital loop
09/07/1982CA1131332A1 Communication system tracking arrangement
08/1982
08/31/1982US4347605 Multiplexed telecommunication systems
08/31/1982US4347409 Key telephone system
08/24/1982US4346261 Speaker phones
08/10/1982CA1129529A1 Speech channel switching networks suitable for use in combination with electronic key telephone sets
08/03/1982CA1129055A1 Method and system for reducing conference bridge oscillations
07/1982
07/08/1982WO1982002306A1 Radiotelephone with hands-free operation
07/06/1982US4338495 Electronic key telephone systems
07/06/1982CA1127329A1 Telephone system without central office
06/1982
06/08/1982US4334126 Control circuit for concurrently monitoring and controlling functions and frequency modulating status information in a digital data network
05/1982
05/18/1982US4330690 Telephone group listening systems
05/11/1982US4329543 Communication system
04/1982
04/27/1982US4327256 Telephone system
04/20/1982CA1122338A1 Line/interface circuit for key telephone systems
04/07/1982EP0048925A1 Circuit for small private telephone exchanges with bidirectional transmission of binary digital signals between a central device and telephone sets connected thereto
04/07/1982EP0048924A1 Arrangement for telephone sets in small private telephone exchanges, in which a bidirectional transmission of digital signals is carried out between these sets and a central device
04/06/1982US4323735 Key telephone line shunt detector circuit
04/06/1982US4323734 Interface circuit for telephone line to equipment signal coupling
03/1982
03/30/1982US4322581 Multifunction telephone with message information and control information circuits for connecting stations and common equipment in a telephone network
03/09/1982US4319086 Voice switch for hands free communication apparatus
03/02/1982US4317959 Speech control circuit
02/1982
02/23/1982CA1118925A1 Audio teleconferencing
02/23/1982CA1118923A1 Telephone set with loudspeaker
02/09/1982US4315110 Multiple line telephone instrument
02/09/1982US4315103 Speech-controlled loudspeaker telephone station circuit
02/02/1982US4314370 Wireless intercommunication system
02/02/1982US4314109 Synchronization system for key telephone system
01/1982
01/05/1982US4309755 Computer input/output arrangement for enabling a simultaneous read/write data transfer
01/05/1982US4309573 Loudspeaking substation circuit
12/1981
12/29/1981US4308427 Hands-free talk-back intercommunication system
12/08/1981US4304969 Power circuit for loudspeaker telephone
11/1981
11/10/1981CA1112382A1 Communication circuit
11/04/1981EP0039109A1 Protective device against the Larsen effect in a loudspeaking telephone apparatus
10/1981
10/27/1981CA1111584A1 Hold control for a key telephone system
10/27/1981CA1111583A1 Key telephone system
10/13/1981CA1110768A1 Method and apparatus for removing room reverberation
10/06/1981US4293740 Hands free answer intercom
10/06/1981CA1110373A1 Hands-free answer arrangement on intercom for key telephone system
09/1981
09/29/1981US4292476 Speech channel switching networks suitable for use in combination with electronic key telephone sets
09/29/1981US4292475 Expandable link telephone intercom system
09/29/1981US4292474 Electronic key telephone system with bi-directional serial data stream station control
09/23/1981EP0036005A1 Duplex amplifyer particularly for interphone
09/22/1981US4291199 Communication system tracking arrangement
09/08/1981US4288871 Digital loop conferencing signal correction arrangement
09/08/1981CA1108789A1 Key telephone unit protective coupler
08/1981
08/28/1981EP0026187A4 Communication system tracking arrangement.
08/19/1981EP0033744A1 Voice controlled switching system
08/05/1981EP0032982A1 Domestic installation for information transmission and application of the installation as interphone system or for activating an alarm
08/04/1981US4282409 Speech networks for telephone sets
07/1981
07/22/1981EP0032205A2 Key-controlled system for alternate, simultaneous or loud-speaking oral communication
07/21/1981US4280022 Key telephone systems
07/07/1981US4277843 Closed-loop telecommunication system
06/1981
06/10/1981EP0030228A2 Speech networks for telephone sets
05/1981
05/19/1981US4268723 Circuits and methods for initializing the loop current of a telephone set
05/12/1981CA1101142A1 Voice-switched telephone set
05/05/1981US4266103 Key telephone exclusion circuit
04/1981
04/22/1981EP0027343A1 A voice detector
04/14/1981US4262171 Telephone system in which communication between stations is controlled by computers at each individual station
04/08/1981EP0026187A1 Communication system tracking arrangement.
04/07/1981US4260857 Office line connection circuit during service interruptions in key telephone apparatus
04/02/1981WO1981000943A1 Duplex amplifyer particularly for interphone
03/1981
03/11/1981EP0024942A1 Circuits and processes for initializing the loop current of a telephone set
03/03/1981US4254306 Key telephone system
02/1981
02/24/1981US4253000 Method and system for reducing conference bridge oscillations
02/24/1981CA1096523A1 Circuit arrangement for preventing feedback
02/24/1981CA1096521A1 Key telephone station set circuit
02/17/1981US4251689 Loudspeaker telephone apparatus
02/04/1981EP0023403A1 A digital loop sharing communication system and a telephone instrument for use therein
01/1981
01/13/1981CA1093717A1 Open loop system for transmitting digital information
01/06/1981US4243837 Telephone transmission installation between interlocutors in a noisy environment
12/1980
12/16/1980CA1091835A1 Intercommunication system
12/02/1980CA1090908A1 Communication system call coverage arrangements
11/1980
11/27/1980WO1980002627A1 Voice controlled switching system
11/25/1980US4236049 Electronic key telephone system
11/18/1980US4234765 Key telephone system
11/12/1980EP0018938A1 Digital time-division multiplex telecommunication system
11/12/1980EP0018845A1 Data handling circuits
11/12/1980EP0018844A1 Telephone systems
11/04/1980CA1089134A1 Telephone station set interface circuit
11/04/1980CA1089129A1 Key telephone intercom line system
10/1980
10/29/1980EP0017835A1 Circuitry for controlling the transmission of digital signals, especially PCM signals, between connection points of a time division multiplexing telecommunication network, especially a PCM network
10/28/1980US4230904 Signal control circuit
10/21/1980CA1088188A1 Multi-link telephone intercom system
10/14/1980US4228324 Key telephone system having interstation signalling during hold condition
10/02/1980WO1980002094A1 Communication system tracking arrangement
09/1980
09/30/1980US4225754 Loudspeaker telephone
09/02/1980US4220827 Telephone signaling circuit
09/02/1980CA1085075A1 Multy-party telephone system
08/1980
08/12/1980CA1083735A1 Control circuit for hands-free telephone
08/12/1980CA1083734A1 Key telephone line circuit tone-on-hold arrangement
08/12/1980CA1083733A1 Key telephone communication path interface
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