| Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881) |
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| 03/11/1987 | EP0213342A2 Programmable ring signal generator |
| 03/11/1987 | CN85102443A Caller display device for semi automatic long distance telephone system |
| 03/10/1987 | US4649234 Circuit arrangement for telecommunications exchange systems, particularly telephone exchange systems, comprising information processing sequential logic systems and traffic measuring devices |
| 03/04/1987 | EP0212761A2 Communications system |
| 03/04/1987 | EP0212654A2 Method and apparatus for disallowing the extension of a call through a network |
| 03/04/1987 | EP0211849A1 Pager system and communication protocol. |
| 03/03/1987 | US4648109 Light emitting diode message waiting lamp circuit |
| 03/03/1987 | US4648108 Conference circuits and methods of operating them |
| 03/03/1987 | US4648089 Digital voice summing for teleconferencing |
| 03/03/1987 | US4647724 Ringing interface card for telephone test equipment |
| 02/26/1987 | WO1987001256A1 Telephone and demodulator |
| 02/26/1987 | DE3529161A1 Circuit arrangement for telecommunications systems, in particular telephone switching systems, with information-polling devices cyclically activating answering stations |
| 02/25/1987 | EP0211675A2 Line terminating apparatus |
| 02/25/1987 | EP0211336A2 Port circuit for coupling an end-user instrument with a port of a communications system |
| 02/25/1987 | EP0211262A2 Method for a private branch exchange in which telephone terminals with various constructions are installed |
| 02/25/1987 | EP0211261A2 Method for automatically testing a communication system, especially a private branch exchange |
| 02/25/1987 | EP0211246A2 Method for a telecommunication exchange, especially a private branch exchange with at least one operator position |
| 02/25/1987 | CN86104257A Communication system with remote-controlled signal receiving apparatus |
| 02/24/1987 | US4646347 Ringing signal reformatting circuit |
| 02/24/1987 | US4646346 Integrated message service system |
| 02/24/1987 | US4646342 Test trunk access controller |
| 02/24/1987 | US4646288 Multi-line accumulator/multiplexer |
| 02/24/1987 | US4645881 DC level trip detector |
| 02/24/1987 | US4645879 Call-routing device |
| 02/24/1987 | US4645874 Message routing through data communication networks |
| 02/24/1987 | US4645872 Videophone network system |
| 02/19/1987 | DE3529056A1 Device for central monitoring of communication systems in networks |
| 02/17/1987 | US4644530 Instant speaker algorithm for digital conference bridge |
| 02/17/1987 | US4644527 Interface unit for transferring voice and data signals |
| 02/17/1987 | US4644437 Telephone subscriber loop overvoltage protection integrated circuit |
| 02/17/1987 | US4644351 Two way personal message system with extended coverage |
| 02/17/1987 | CA1218171A1 Personal-calling communication system |
| 02/17/1987 | CA1218137A1 Telephone cable encapsulating splice housing |
| 02/12/1987 | WO1987000995A1 An intermediate amplifier for use in two-wire connections of a dial telephone network and a method for the gain control of said amplifier |
| 02/11/1987 | CN86102081A Speakerphone sensing circuit |
| 02/11/1987 | CN86101291A Selecting arrangements for multiplex systems |
| 02/10/1987 | US4642805 Digital link for telephone station sets |
| 02/10/1987 | US4642697 Facsimile relay device |
| 02/10/1987 | CA1217888A Subscriber's telephone hold circuit with automatic disconnect |
| 02/04/1987 | EP0210798A2 Programmable data-routing multiplexer |
| 02/04/1987 | EP0210797A2 Digital Subscriber controller |
| 02/03/1987 | US4641376 Multi-channel multi-cell optoelectronic switching networks for multi-service telecommunications systems |
| 02/03/1987 | US4641302 High speed packet switching arrangement |
| 02/03/1987 | US4641299 Mechanized loop testing using a local metallic access port |
| 02/03/1987 | US4640992 Speech response interface circuit |
| 02/03/1987 | US4640991 Electronic audio communications systems network |
| 01/31/1987 | CN85102113A Audio frequency transmission circuit formed by line-voltage stabilizer type transmitting amplifier |
| 01/31/1987 | CN85101395A Wideband high voltage amplifier for telephone exchange subscriber line interface utilizing low voltage control circuitry |
| 01/31/1987 | CN85101387A Signal transmitting system of master-control telephone set |
| 01/28/1987 | EP0209973A1 Protection arrangement for a telephone subscriber line interface circuit |
| 01/27/1987 | US4639557 Remote testing system for electrical circuits |
| 01/27/1987 | US4639555 Pair cut apparatus and method of use |
| 01/27/1987 | CA1217286A1 Maintenance termination unit |
| 01/27/1987 | CA1217261A1 Method and apparatus for sending a data message to a selected station during a silent interval between ringing |
| 01/21/1987 | EP0208991A2 Line switching method and system |
| 01/21/1987 | EP0208875A1 Circuit for the separation of the direct and alternating current portions of a signal mixture |
| 01/20/1987 | US4638123 Circuit arrangement for a small PABX with a switching matrix that has electronic crosspoints |
| 01/20/1987 | CA1216977A1 Multiplexer system |
| 01/20/1987 | CA1216958A1 Voice/text storage and retrieval system |
| 01/15/1987 | WO1987000375A1 Statistical analysis system for use with public communication facility |
| 01/15/1987 | DE3525566A1 Circuit arrangement for identifying earth key functions in telephone switching systems |
| 01/14/1987 | EP0208648A2 Method for automatically testing centrally controlled communication systems, especially those of private branch exchanges |
| 01/13/1987 | US4636939 Parallel bus protocol |
| 01/13/1987 | CA1216690A1 Telephone line circuit having time-shared dtmf receivers |
| 01/13/1987 | CA1216651A1 System for linking channel group in digital communication network |
| 01/10/1987 | CN85101046A Keyboard for telephone trunk control desk |
| 01/07/1987 | EP0207255A1 Arrangement for operating and maintaining a telecommunication exchange, especially a telephone exchange |
| 01/07/1987 | EP0207214A2 Method of and apparatus for controlling data flow through a subsystem of a data communication network |
| 01/06/1987 | US4635255 Digital subscriber controller |
| 01/06/1987 | US4635253 Exchange system including plural terminals for voice and data transmission |
| 01/06/1987 | US4635252 Conference circuit for digital communication systems |
| 01/06/1987 | US4635251 Meet-me conference with control capabilities |
| 01/06/1987 | US4634811 Call screening system |
| 01/06/1987 | CA1216349A1 Method and apparatus for providing a plurality of special services |
| 12/31/1986 | CN85105268A Telephone auto-exchange technology with frequency shared call in the same wire |
| 12/30/1986 | US4633459 Repeater for carrier subscriber communication system |
| 12/30/1986 | US4633043 Apparatus for use with key telephone systems |
| 12/30/1986 | US4633041 Station set directory assistance arrangement |
| 12/30/1986 | EP0206403A2 High speed packet switching arrangement |
| 12/30/1986 | EP0206279A1 Circuit arrangement for the noiseless injection of sinusoidal AC pulses, especially metering pulses of 16 kHz |
| 12/30/1986 | EP0205919A1 Circuit arrangement for telecommunication exchanges, particularly telephone exchanges, comprising central control devices receiving information-processing orders from distributed control devices |
| 12/30/1986 | EP0205543A1 An arrangement in a telephone exchange |
| 12/30/1986 | CA1216068A1 Programmable coding and decoding arrangement |
| 12/30/1986 | CA1216050A1 Call transfer method and circuitry |
| 12/24/1986 | CN85104001A Digital timeslot and signaling bus in a digital pbx switch |
| 12/23/1986 | US4631720 Service integrated transmission system |
| 12/23/1986 | US4631475 Method of detecting hazardous line voltages over a two-wire line |
| 12/23/1986 | US4631368 Switching system for readily accessing the service line for test basic unit and the switching system for readily accessing the service line for test expansion unit |
| 12/23/1986 | US4631364 Communication system having dynamically assigned station set buttons |
| 12/23/1986 | US4631363 Method and apparatus for incremental load simulation |
| 12/23/1986 | US4631362 Low resistance origination scan circuit |
| 12/17/1986 | EP0201126A2 Integrated services radio transmission system |
| 12/17/1986 | CN86201443U Device for guarding against the user's calling for preset telephone number |
| 12/16/1986 | US4630262 Method and system for transmitting digitized voice signals as packets of bits |
| 12/16/1986 | US4629836 Method and apparatus for accessing communication systems |
| 12/16/1986 | US4629835 Fault isolating apparatus system and method |
| 12/16/1986 | US4629832 Communication system administration method and circuitry |
| 12/16/1986 | US4629831 Series connected interceptor |
| 12/16/1986 | US4629830 Telecommunications system, particularly a telephone exchange system, having overload protected sequential logic systems |
| 12/16/1986 | CA1215485A1 Ringing generator testing arrangement for a digital telephone network |