| Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881) |
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| 03/07/1989 | US4811333 Substantially non-blocking space switching arrangement |
| 03/07/1989 | CA1250938A1 Controlling multi-port hunt groups in a distributed control switching system |
| 03/07/1989 | CA1250909A1 Transmission line signal sensing circuit employing means for conserving power, especially for use with a telephone disconnect circuit, and associated method |
| 03/01/1989 | EP0304653A2 Method and arrangement for storing telecommunication messages in a private telecommunication exchange |
| 03/01/1989 | EP0304652A2 Method for a programme-controlled telephone exchange by which service features concerning the realisation of a speech connection are introduced from a subscriber terminal |
| 02/28/1989 | US4809324 Subscriber line interface circuit (SLIC) isolation from lighting-induced ground overshoots |
| 02/28/1989 | US4809321 Busy/no-answer call completion equipment |
| 02/28/1989 | US4809318 Method of overload control for the central control of a telecommunication system and arrangement for implementing the method |
| 02/28/1989 | US4809270 Variable time slot communication system |
| 02/28/1989 | US4809262 Method of making conference call connections in computer-controlled digital telephone exchanges |
| 02/28/1989 | US4809258 Circuit arrangement for the indication of loop closure during the ringing condition |
| 02/28/1989 | CA1250673A1 Subscriber rf telephone system for providing multiple speech and/or data signals simultaneously over either a single or a plurality of rf channels |
| 02/23/1989 | DE3727223A1 Communication system for carrying out various special communication services |
| 02/22/1989 | EP0303870A2 Modular structured digital communication system with operational and reliable components |
| 02/21/1989 | US4807279 Remotely programmable call forwarding control device |
| 02/21/1989 | US4807277 Remotely activated switching apparatus |
| 02/21/1989 | US4807275 Dispatch board system with displays for indicating the status of various messages |
| 02/21/1989 | US4807274 Telephone line quality testing system |
| 02/21/1989 | CA1250381A1 Supervisory system in communication system |
| 02/16/1989 | DE3801544C1 Test switch for optionally connecting a special device or an automatic measuring or test line circuit to an analog line coming from a telephone exchange |
| 02/16/1989 | DE3725882A1 Method and device for transmitting signals of a telephone appliance |
| 02/15/1989 | EP0303142A1 Method for measuring line parameters of subscriber lines of a telecommunication network |
| 02/15/1989 | EP0302957A1 Device for signalling a message in a telephone system |
| 02/14/1989 | US4805211 Subscriber set programming module |
| 02/14/1989 | US4805209 Coordinated transfer of voice and information through a digital switch |
| 02/14/1989 | US4805207 Message taking and retrieval system |
| 02/14/1989 | US4805205 Method and device for establishing bidirectional communications between persons located at different geographically distant stations |
| 02/09/1989 | WO1989001277A1 Controlling key-system groups from a distributed control switching system |
| 02/09/1989 | DE3725061A1 Arrangement for monitoring multi-digit subscriber numbers for telecommunications exchanges, especially telephone exchanges |
| 02/09/1989 | DE3724847A1 Method for storing telecommunications information |
| 02/07/1989 | USH586 ISDN D channel handler |
| 02/07/1989 | US4803720 Dual plane cross point switch architecture for a micro-PBX |
| 02/07/1989 | US4803718 Hold detecting and control circuit for a key telephone system |
| 02/01/1989 | EP0301957A1 Method and circuit for control of audio conferences |
| 01/31/1989 | US4802209 Paging system for electronic telephone apparatus |
| 01/31/1989 | US4802207 Voltage-sensitive telephone line monitor |
| 01/31/1989 | US4802206 Calling system for enabling speech transmission from a caller to a called busy party in a telephone system |
| 01/31/1989 | US4802205 Circuit arrangement for telecommunications switching systems, particularly for telephone switching systems comprising information-processing sequential logic systems and traffic measuring devices |
| 01/31/1989 | US4801936 Broadband signal switching apparatus |
| 01/31/1989 | CA1249648A1 Adaptive trunk-compression system with constant grade of service |
| 01/26/1989 | WO1989000793A1 Directory assistance systems |
| 01/25/1989 | EP0300607A2 Ring shaped local area network for digital audio |
| 01/25/1989 | CN2031589U Capacity expanding device for crossbar switch |
| 01/24/1989 | US4800583 Overflow call handling system |
| 01/24/1989 | CA1249382A1 Arrangement for operating and maintaining a telecommunications system |
| 01/19/1989 | DE3722921A1 Method for a computer-controlled private telephone branch exchange, particularly for a key system, with the possibility of inserting an attention signal in the busy case |
| 01/18/1989 | EP0299784A2 Feature telephone integration device |
| 01/18/1989 | CN2031184U User exchanger bell current generator with detector |
| 01/17/1989 | US4799255 Communication facilities access control arrangement |
| 01/17/1989 | US4799251 ESS equipment testing device |
| 01/17/1989 | US4799213 Data transmission system |
| 01/17/1989 | US4799144 Multi-function communication board for expanding the versatility of a computer |
| 01/11/1989 | EP0298621A2 System for measuring and automatically compensating for the distortions of a connection between a telephone apparatus and a central voice processing unit |
| 01/11/1989 | CN1030334A Battery feed circuit |
| 01/10/1989 | US4797931 Audio frequency signal identification apparatus |
| 01/10/1989 | US4797913 Direct telephone dial ordering service |
| 01/10/1989 | US4797911 Customer account online servicing system |
| 01/10/1989 | US4797910 Automated operator assistance calls with voice processing |
| 01/10/1989 | US4797877 Communication system dynamic conferencer circuit |
| 01/10/1989 | US4797876 Conferencing bridge |
| 01/10/1989 | US4797875 Method for monitoring and controlling the traffic in digital transmission networks |
| 01/10/1989 | US4797622 Technique for determining the values of circuit elements in a three terminal equivalent circuit |
| 01/10/1989 | CA1248617A1 Parallel call processing system and method |
| 01/10/1989 | CA1248616A1 Telephone switching system switch processor interface |
| 01/10/1989 | CA1248615A1 Computerized system for routing incoming telephone calls to a plurality of agent positions |
| 01/10/1989 | CA1248604A1 Loop around data channel unit |
| 01/04/1989 | CN2030399U Recorder for telephone exchange fault |
| 01/04/1989 | CN1030169A Protection arrangement for telephone subscriber line interface circuit |
| 01/04/1989 | CN1030168A Call monitor arrangement |
| 01/03/1989 | US4796293 Enhanced dedicated teleconferencing system |
| 01/03/1989 | US4796289 Multi-line network interface |
| 01/03/1989 | CA1248252A1 Key telephone system |
| 01/02/1989 | EP0229170A4 Statistical analysis system and method for use with public communication facility. |
| 12/29/1988 | WO1988010539A1 Apparatus for achieving a controllable line termination impedance |
| 12/29/1988 | DE3720186A1 Method for a computer-controlled switching system, in particular a so-called KEY telephone switching system |
| 12/28/1988 | EP0296832A2 A call monitor arrangement |
| 12/28/1988 | CN87104288A Operation mode of charge system of crossbar telephone switchboard |
| 12/28/1988 | CN87104284A Operation mode of crossbar telephone switchboard management system |
| 12/27/1988 | US4794640 Switching control apparatus for intercom-telephone sets |
| 12/27/1988 | US4794639 Method and apparatus for automatically transmitting a message to a telephone terminal |
| 12/27/1988 | US4794633 Mass polling system |
| 12/27/1988 | US4794632 Telephone trunk line testing circuitry |
| 12/27/1988 | US4794595 Voice and data transmission system |
| 12/27/1988 | US4794591 Digital voice switch for a multi-port conference circuit |
| 12/21/1988 | EP0295904A2 Address management system |
| 12/21/1988 | EP0295837A2 Customer account online servicing system |
| 12/21/1988 | EP0295683A2 Protection circuit for battery feed circuit |
| 12/21/1988 | EP0295470A2 Method for a calculator controlled switching device especially for a so called key telephone exchange with the possibility of call transfer |
| 12/20/1988 | US4792970 Expansion port for use in a communication system |
| 12/20/1988 | US4792968 Statistical analysis system for use with public communication facility |
| 12/20/1988 | US4792967 PBX DID and E and M tie trunk integration adapter and method |
| 12/20/1988 | US4792941 Data subsystem traffic control apparatus and method |
| 12/20/1988 | US4792921 Data processing node |
| 12/13/1988 | US4791663 Telephone status recognition and bypass system |
| 12/13/1988 | US4791662 Controlling key-system groups from a distributed control switching system |
| 12/13/1988 | US4791660 Variable data compression announcement circuit |
| 12/13/1988 | US4791659 Remote test telephone line access system |
| 12/13/1988 | CA1246726A1 Arrangement for communication between equipment belonging to different network architectures |
| 12/13/1988 | CA1246725A1 Digital conference circuit |
| 12/07/1988 | EP0294303A1 Circuit for a telephone set comprising a protection against voltage overloading |