| Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881) |
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| 03/24/1988 | WO1988002206A1 Communication interface |
| 03/24/1988 | WO1988002205A1 Communication system |
| 03/24/1988 | WO1988000786A3 Security arrangement for a telecommunications exchange system |
| 03/24/1988 | DE3631168A1 Method for exchanging input and output procedures between external subscriber installation and a switching system with V24 interface |
| 03/23/1988 | EP0260839A2 Protection arrangements for communications lines |
| 03/23/1988 | CN86106026A System for interfacing a standard telephone set with a radio transceiver |
| 03/16/1988 | EP0259447A1 Telecommunication network and methods relating thereto. |
| 03/15/1988 | US4731829 Circuit for detecting current variations |
| 03/15/1988 | US4731827 Interswitch line circuit |
| 03/15/1988 | US4731824 Chime pulser for phone call backup interpreter |
| 03/15/1988 | US4731822 Held party notification feature |
| 03/15/1988 | US4731817 Multi-processing stored program controlled telecommunication establishment |
| 03/15/1988 | CA1234234A1 Method and apparatus for testing remote communication systems |
| 03/15/1988 | CA1234209A1 Telephone line access system for main distribution frame |
| 03/10/1988 | WO1988001821A1 Telephone configuration of the hands-free type for teleconferences |
| 03/10/1988 | WO1988001820A1 Control of the amplification of signals transmitted in a bidirectional and simultaneous way |
| 03/10/1988 | DE3629938A1 Circuit arrangement with an electronic choke |
| 03/10/1988 | DE3629937A1 Circuit arrangement with an electronic choke |
| 03/09/1988 | EP0259053A2 Variable data compression announcement circuit |
| 03/09/1988 | CN87207227U Tester of telephone general wiring support |
| 03/08/1988 | US4730306 Conference system |
| 03/08/1988 | US4730303 Digital switching system with host and remote duplicated transmission controllers |
| 03/08/1988 | US4730302 Monitoring means for digital signal multiplex equipment |
| 03/08/1988 | CA1233924A1 Telephone line status circuit |
| 03/03/1988 | DE3629468A1 Method for a computer-controlled switching system, particularly a telephone branch exchange |
| 03/02/1988 | EP0257672A1 Digital telecommunication system comprising an exchange and a group of multi-access telephone terminals |
| 03/02/1988 | EP0257314A2 Method to guarantee the operation of a programme-controlled switching exchange |
| 03/01/1988 | US4729126 Method and apparatus for supervising the accessing and testing of communication systems |
| 03/01/1988 | CA1233583A1 Protection arrangement for a telephone subscriber line interface circuit |
| 03/01/1988 | CA1233578A1 Data entry and display control circuit |
| 02/24/1988 | EP0256291A2 Circuit for the separation of the direct and alternating current portions of a signal mixture |
| 02/24/1988 | CN87200552U Compatible central battery toll switchboard |
| 02/24/1988 | CN87105391A Digital telecommunication system comprising an exchange and a group of multi-access telephone terminals |
| 02/24/1988 | CN87103996A Communication system having unified messaging |
| 02/23/1988 | US4727567 Operator station for telephone exchange |
| 02/23/1988 | CA1233283A1 Subscriber line interface circuit with longitudinal current suppression |
| 02/17/1988 | EP0255903A2 Processor-controlled telephone exchange with a central operation device and operation terminals |
| 02/16/1988 | US4726060 Line circuit for driving a ringer and a service indicating lamp in a telephone set |
| 02/16/1988 | US4726016 Conference system |
| 02/16/1988 | CA1232988A1 Subscriber line interface circuit with improved d.c. balance |
| 02/11/1988 | DE3726366A1 Communication network and communication transmission process |
| 02/10/1988 | CN87105312A Modular structure of integrated service data network communication system of producing and displaying fault literal information |
| 02/10/1988 | CN86204718U Semi-automatic cross-bar telephone switchboard for subscriber |
| 02/09/1988 | US4724539 Call forwarding reprogramming device |
| 02/09/1988 | US4724379 Relay multiplexing for circuit testers |
| 02/09/1988 | CA1232664A1 Message waiting alerting method |
| 02/09/1988 | CA1232663A1 Instant speaker algorithm for digital conference bridge |
| 02/09/1988 | CA1232662A1 Digital teleconferencing control device, system and method |
| 02/09/1988 | CA1232660A1 Fault detection arrangement for a digital conferencing system |
| 02/03/1988 | EP0255325A2 Call transfer between a message service system and a telephone switching system |
| 02/03/1988 | EP0254743A1 Pay-per-view catv system. |
| 02/03/1988 | CN87202234U Redialing device of telephone |
| 02/02/1988 | US4723273 Discretionary call forwarding |
| 02/02/1988 | US4723272 Telecommunication system, in particular telephone system |
| 02/02/1988 | US4723270 Traffic data collecting arrangement comprising a template data memory in each exchange |
| 02/02/1988 | CA1232379A1 Digital link for telephone station sets |
| 01/28/1988 | WO1988000786A2 Security arrangement for a telecommunications exchange system |
| 01/28/1988 | EP0138951A4 A self routing steering network. |
| 01/28/1988 | DE3625350A1 Method for a telecommunication branch exchange, particularly a telephone branch exchange |
| 01/28/1988 | DE3624563A1 Method for electronically simulating the line connected and switch-over contacts in telephone stations fed via the subscriber line and having two subscriber lines |
| 01/28/1988 | DE3623534A1 Method of preventing overloading of the central processor of a telephone switching system |
| 01/27/1988 | EP0254559A2 Security arrangement for a telecommunications exchange system |
| 01/27/1988 | EP0254116A2 Circuit arrangement for adaptation of a two-wire subscriber line circuit for the connection with a coupling device with single wire interconnection in telephone exchanges, especially private branch exchanges |
| 01/27/1988 | EP0254115A1 ISDN communication system of modular structure with creation and indication of fault texts |
| 01/27/1988 | CN87204824U Communication device for city telephone |
| 01/27/1988 | CN87200222U Universal telephone distribution frame protector capable of operating at the front |
| 01/26/1988 | CA1232024A1 Multi-channel access (mca) radio telephone system |
| 01/21/1988 | DE3623535A1 Circuit arrangement for controlling voice announcements in digital telephone switching systems |
| 01/20/1988 | EP0253421A1 Communication network, more specifically a telephone network and data communication network composed of a set of nodes, in which specific facilities within optionally determined domains can be offered fully integrated |
| 01/20/1988 | CN87206467U Vertical and horizontal style automatic out-telephone-trunk-line expander |
| 01/19/1988 | US4720853 Ring signal discriminator |
| 01/19/1988 | US4720848 Communication system with voice announcement means |
| 01/19/1988 | US4720845 Protective circuit for the overvoltage protection of a subscriber line interconnect circuit |
| 01/19/1988 | CA1231771A1 Multi-processing stored program controlled telecommunication establishment |
| 01/14/1988 | WO1988000418A1 Telephone on-hold device |
| 01/13/1988 | EP0252872A2 Circuit arrangement for determining subscriber loop conditions (constant current feeding) |
| 01/13/1988 | CN87104413A Railway basic unit service automatic communication system |
| 01/13/1988 | CN87104377A Isdu d channel handler |
| 01/12/1988 | US4719647 Telephone message retrieval system with improved processor and retrieval console |
| 01/12/1988 | US4719618 Digital conference circuit |
| 01/12/1988 | US4719617 Communication system |
| 01/12/1988 | CA1231479A1 Communication system having dynamically assigned station set buttons |
| 01/12/1988 | CA1231477A1 Communication system with operation-procedure guiding function by speech |
| 01/12/1988 | CA1231383A1 Two-way personal message system with extended coverage |
| 01/07/1988 | EP0251038A1 Device for disconnecting the wires of a subscriber connection line from the powering circuit |
| 01/07/1988 | EP0250936A1 Method for controlling the information transmission of switched four-wire connections, especially semi-permanent switched connections in digital TDM exchanges |
| 01/07/1988 | DE3620925A1 Method for user guidance on a digital telephone station |
| 01/06/1988 | CN85108230B Ringing signal sending circuit |
| 01/05/1988 | US4718084 Overload protection circuit for a telephone subscriber line feed circuit |
| 12/29/1987 | US4716585 Gain switched audio conferencing network |
| 12/29/1987 | US4716583 Verbal computer terminal system |
| 12/23/1987 | EP0250075A2 ISDN D channel handler |
| 12/23/1987 | EP0249836A1 Switching device for broad-band signals |
| 12/23/1987 | EP0249795A2 Method for a communication system, especially for a private telephone system, in which at times a switching to changed traffic possibilities occurs |
| 12/22/1987 | US4715058 Protective circuit for the overvoltage protection of a subscriber line interconnect circuit |
| 12/22/1987 | US4715032 Method and apparatus for the connection of a closed ring through a telephone exchange |
| 12/17/1987 | WO1987007801A1 Communication system having unified messaging |
| 12/17/1987 | WO1987007799A1 A telephone line monitoring system |
| 12/16/1987 | EP0249575A2 Computerized communications system |
| 12/16/1987 | EP0248812A1 Method and apparatus for efficient resource allocation. |