| Patents for H04M 9 - Arrangements for interconnection not involving centralised switching (8,105) |
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| 11/25/1992 | EP0515242A1 Method for optimizing the quality of telephone communications |
| 10/31/1992 | WO1992020170A1 Voice communication device provided with echo canceler |
| 10/29/1992 | WO1992019048A1 Device for treating the residual echo of a cancellor which cancels the echo signal of a digital speech signal |
| 10/15/1992 | WO1992017988A1 Telephone set |
| 10/14/1992 | EP0508093A2 Method for the transmission of the busy state in a communication system, especially in a key-controlled telephone exchange for alternate a simultaneous communication and device for carrying out the method |
| 10/14/1992 | CN2119056U Ac line transmission multi-channel digit telephone set |
| 10/07/1992 | CN1065170A A.c duplex carrier telphony set |
| 10/06/1992 | US5153908 Automatic redial in a key telephone system having different line types |
| 10/06/1992 | CA1308441C Hands-free telephone |
| 09/29/1992 | US5151934 Key telephone apparatus |
| 09/29/1992 | US5151933 Key telephone system |
| 09/29/1992 | US5151896 Modular digital telephone system with fully distributed local switching and control |
| 09/16/1992 | EP0503660A2 Multi-channel echo canceling method and apparatus |
| 09/16/1992 | EP0503412A2 Key-controlled multi-line telephone system for alternate, simultaneous or loud-speaking and communication |
| 09/15/1992 | CA1307602C Telephone intercom device |
| 09/09/1992 | CN2115626U Automatic intercall telephone |
| 09/03/1992 | WO1992015167A1 Telephone adapter for telephone sets |
| 09/02/1992 | EP0501783A2 Speakerphone with serial port interface |
| 09/02/1992 | EP0501451A2 Method and arrangement for generating tap-coefficients updating inhibit signal in speakerphone |
| 08/26/1992 | EP0500356A2 Loudspeaker telephone device comprising a noise suppressing circuit |
| 08/26/1992 | CN2114248U Two-way wire talkback speaker |
| 08/26/1992 | CN2114247U Ac duplex carrier telephong set |
| 08/25/1992 | US5142569 Apparatus for selectively enabling subscriber device to respond to ringing signal in dependence upon ringing cadence |
| 08/25/1992 | US5142532 Communication system |
| 08/18/1992 | US5140628 Radio telephone system control method |
| 08/11/1992 | US5138656 Intercom with transducer enclosure to attenuate resonant frequencies |
| 08/11/1992 | US5138655 Telephone apparatus capable of setting card unit therein |
| 08/04/1992 | US5136630 Intrinsically safe telephone |
| 08/04/1992 | US5136585 Digital key telephone system |
| 08/04/1992 | US5136577 Sub-band acoustic echo canceller |
| 07/28/1992 | US5134658 Apparatus for discriminating information signals from noise signals in a communication signal |
| 07/23/1992 | WO1992012589A1 Voice-switched handset receive amplifier |
| 07/22/1992 | EP0495360A2 Arrangement for volume control in a hands free telephone device |
| 07/14/1992 | US5131048 Audio distribution system |
| 07/14/1992 | US5131032 Echo canceller and communication apparatus employing the same |
| 07/10/1992 | WO1992012606A1 Improved audio distribution system |
| 07/07/1992 | US5128989 Key telephone system with circuitry for adding a third caller to a multiple party connection |
| 07/05/1992 | WO1992012583A1 Adaptive acoustic echo canceller |
| 07/01/1992 | EP0492049A2 Distributed telephone conference control device |
| 06/24/1992 | EP0491430A1 Echo canceller with improved doubletalk detection |
| 06/23/1992 | US5125026 Internal telephone intercom system |
| 06/09/1992 | US5121426 Loudspeaking telephone station including directional microphone |
| 06/03/1992 | EP0488827A1 Interphone |
| 06/02/1992 | US5119418 Telephone system with several terminals on a single line |
| 05/27/1992 | EP0486990A2 Auxiliary attenuator arrangement for use in voice-switched speakerphone and method of selectively inserting communication loss in speakerphone paths |
| 05/26/1992 | US5117372 Graphics-assisted terminal administration arrangement |
| 05/20/1992 | EP0486391A1 Digital private branch exchange with direct internal switching |
| 05/20/1992 | CN2105153U Two-end telephong liaison device |
| 05/19/1992 | CA1301293C Key telephone system |
| 05/19/1992 | CA1301073C Voice enhancer system |
| 05/13/1992 | EP0484793A1 Digital audio communication system including a central processing unit and a communication station |
| 04/29/1992 | EP0482745A2 Method for operating an apparatus for facilitating communications |
| 04/29/1992 | EP0481976A1 Intercom telephone |
| 04/02/1992 | WO1992005643A1 Modular digital telephone system with fully distributed local switching and control |
| 04/01/1992 | EP0478129A2 Apparatus for facilitating communications |
| 04/01/1992 | EP0478125A2 Discriminating information from noise in a communication signal |
| 03/24/1992 | US5099472 Hands free telecommunication apparatus and method |
| 03/24/1992 | CA1297973C Feature telephone integration device |
| 03/19/1992 | DE4111820A1 Acoustic feedback elimination circuitry for loudspeaking telephone - uses frequency detectors controlling level of attenuation device |
| 03/18/1992 | EP0475135A1 Transmission system for connection network in communication networks |
| 03/17/1992 | US5097501 Key telephone interface |
| 03/17/1992 | CA1297566C Implied principal busy status indicator for covered calls |
| 03/11/1992 | EP0263157B1 Method and device for transferring signals between modules of an electronic unit |
| 03/11/1992 | CN1059441A Duplex centerless frequency-division multiple access carrier telephone system |
| 03/04/1992 | EP0204718B1 Full duplex speakerphone for radio and landline telephones |
| 02/26/1992 | EP0472348A2 Economical videoconference system |
| 02/26/1992 | EP0472289A2 Speakerphone state-controlled alerting arrangement |
| 02/23/1992 | CA2047373A1 Economical videoconference system |
| 02/19/1992 | EP0471083A1 Speaking device having hand-free conversational function |
| 02/18/1992 | US5090052 Telephone system with multiple extension telephones |
| 02/12/1992 | EP0470548A1 Method for controlling attenuation in a digital hands-free telephone set |
| 02/12/1992 | CN1058685A Multi-user self-selection talking system |
| 02/05/1992 | EP0469114A1 A method for active feedback suppression |
| 02/04/1992 | US5086458 Telephone answering system and apparatus for direct caller selection of a party line extension |
| 01/22/1992 | EP0466855A1 Speakerphone for cellular telephones with howl prevention |
| 01/16/1992 | DE4021787A1 Electro-acoustic system e.g. for telephone appts. - controls coupling between loudspeaker and microphone via space to suppress acoustic feedback using filter and/or modulator |
| 01/07/1992 | CA1294082C Adaptive expander for telephones |
| 01/07/1992 | CA1294081C Loudspeaking telephone with a variable gain circuit |
| 01/02/1992 | EP0463832A2 Control and interface apparatus for telephone systems |
| 01/02/1992 | EP0463831A2 Key telephone interface |
| 12/31/1991 | US5077682 Apparatus and method for displaying duration of a call made over a central office line in a keyphone system |
| 12/31/1991 | CA1293832C Telecommunications line interface circuits |
| 12/27/1991 | EP0462890A2 Communications systems |
| 12/26/1991 | WO1991020149A1 Echo canceller with adaptive voice switch attenuation |
| 12/24/1991 | US5075687 Echo suppression with both digital and analog variable attenuators |
| 12/18/1991 | CN1015141B Non-cord telephonic system |
| 12/17/1991 | US5073923 Private telephone system with unified command feature |
| 12/11/1991 | EP0461029A1 Trans-controller method and device for installation and distribution of television programmes with conditional access |
| 12/03/1991 | US5070524 Telephone system |
| 11/28/1991 | DE4016629A1 Service telephone unit with dual-tone multi-frequency decoder - protects service conversations by provision of engaged tone from internal generator and switch operated by microcontroller |
| 11/27/1991 | EP0458710A1 Telephone system with a plurality of telephone terminals on a single line |
| 11/14/1991 | WO1991017617A1 Speech-transmission system |
| 11/14/1991 | DE4014132A1 Sprachuebertragungssystem Sprachuebertragungssystem |
| 11/05/1991 | CA1291837C Electronic telephone terminal having noise suppression function |
| 10/31/1991 | DE4013961A1 Building internal telephone installation - has one or more stations with access to exchange line and common entrance-door station for security |
| 10/31/1991 | DE4013387A1 Telephone system operation - in which main phone is controlled by central controller and extensions can be added by 4-line |
| 10/30/1991 | CN1055854A Private telephone system with simplified command feature |
| 10/29/1991 | US5062151 Communication system |
| 10/24/1991 | DE4012354A1 Damping regulation system for hands-free telephone - has switching between 2 different pairs of measuring points dependent on speech direction |
| 10/23/1991 | EP0452734A2 Hands free telephone device |