Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 7 - Arrangements for interconnection between switching centres
Patents for H04M 7 - Arrangements for interconnection between switching centres (24,777)
08/1982
08/25/1982EP0058470A1 Trunk interface circuit with current compensation
08/17/1982US4345117 Telephone line feed circuit
08/17/1982CA1130027A1 Adaptive electronic hybrid circuit
07/1982
07/20/1982CA1128224A1 Call for service and continuity sensor circuit
06/1982
06/29/1982US4337376 Communications system and network
05/1982
05/13/1982WO1982001633A1 Arrangement at telephone exchanges,particularly for connecting such exchanges with each other for example through a line separated from the public telephone network
05/04/1982CA1123131A1 Transformerless trunk circuit
04/1982
04/20/1982US4326104 Current detector
04/13/1982CA1121892A1 Ring sensing circuit for use with a service evaluation system
04/07/1982EP0048868A1 Communications system, especially telephone system
03/1982
03/23/1982US4321431 Trunk circuit with single coupling transformer
03/16/1982CA1120145A1 Method and arrangement for controlling traffic over two-way trunks
01/1982
01/26/1982US4313036 Distributed CBX system employing packet network
01/19/1982US4311879 AC Supervisory signal detector circuit
01/12/1982US4310727 Method of processing special service telephone calls
01/12/1982US4310725 Interface for private branch exchange
01/12/1982CA1116328A1 Detector circuit for sensing battery polarity and loop closure
12/1981
12/16/1981EP0041902A1 Method and device to establish bidirectional and/or multidirectional communications between different persons grouped in different geographically distant locations connected to each other by telephone lines
10/1981
10/27/1981CA1111585A1 Ac supervisory signal detector circuit
09/1981
09/30/1981EP0036800A1 Device for linking a private telephone network to the public network
09/29/1981US4292479 Separation and balance device for telephone exchanges
09/15/1981CA1109169A1 Method and apparatus for signalling and framing in a tdm communication system
09/09/1981EP0035181A2 Arrangement for the individual channel release and locking of telephone channels in signal converters of a time division multiplex system for pulse code modulation
09/01/1981CA1108325A1 Telecommunications system
08/1981
08/18/1981US4284859 Adaptive electronic hybrid circuit
04/1981
04/28/1981US4264786 A.C. Signal current transmission trunk circuit for telephone exchange systems
01/1981
01/13/1981CA1093717A1 Open loop system for transmitting digital information
01/06/1981CA1093019A1 Ported closure and connector therefor
10/1980
10/14/1980US4228323 Variable loop length compensated barrier circuit
09/1980
09/09/1980CA1085498A1 Multi-frequency code signaling between registers
08/1980
08/20/1980EP0014328A1 Busy-circuit for the "incoming" c-conductor in a telecommunication device
07/1980
07/29/1980CA1082823A1 Time division system for synchronizing functions controlled by different clocks
04/1980
04/22/1980US4199665 Method and arrangement for controlling traffic over two-way trunks
02/1980
02/26/1980US4190745 Call for service and continuity sensor circuit
01/1980
01/08/1980US4182936 Transformerless trunk circuit
12/1979
12/13/1979WO1979001093A1 Method of simplifying line selection in a telecommunication exchange in which the lines can be seized from this exchange as well as from a remote exchange
12/11/1979US4178486 Ring sensing circuit for use with a service evaluation system
12/11/1979CA1067986A1 Line protection switching system
11/1979
11/28/1979EP0005687A1 Method of simplifying line selection in a telecommunication exchange in which the lines can be seized from this exchange as well as from a remote exchange
08/1979
08/28/1979US4166198 Process for operating sub-zones of a digital t.d.m. telecommunications network for long distance traffic
07/1979
07/17/1979US4161630 Circuit arrangement for use in telephone systems
06/1979
06/12/1979CA1056527A1 Power fail monitor and transfer circuit for private branch exchange
05/1979
05/01/1979CA1053782A1 Telephone line transfer circuit
04/1979
04/24/1979CA1053392A1 telephone connector interconnectingtwo automatic exchanges
02/1979
02/27/1979CA1049638A1 Return answer supervisory circuit
02/13/1979US4139739 Telecommunications call back system
01/1979
01/16/1979US4135061 Device for blocking a junctor of an automatic switching system
01/09/1979US4133982 AC supervisory signal detector circuit
12/1978
12/26/1978CA1045215A1 Automatic disconnect circuit for subscriber carrier telephone system
11/1978
11/21/1978US4126765 Detector circuit for sensing battery polarity and loop closure
11/14/1978US4125745 Method and apparatus for signaling and framing in a time division multiplex communication system
10/1978
10/10/1978US4119805 Line-control unit for telecommunication system
10/10/1978US4119804 Open loop system for transmitting digital information
08/1978
08/29/1978US4110565 Duplex telephone signalling system
02/1978
02/21/1978US4075431 Speech path system
11/1977
11/15/1977US4058685 Interoffice loop supervision arrangement
11/08/1977US4057695 Telecommunication system with controlled gain active filters
10/1977
10/11/1977US4053717 Cordless telephone
10/11/1977US4053709 Telephone connector
09/1977
09/20/1977US4049919 Communication system trunk circuit
07/1977
07/19/1977US4037120 Electronic dipole for looping a telephone line
05/1977
05/17/1977US4024359 Continuity-checking network for telecommunication system
05/10/1977US4022258 Ported closure and connector therefor
04/1977
04/12/1977US4017690 Guard circuit for ground start telephone equipment
03/1977
03/22/1977US4013956 Telecommunication system with automatically switched modems
02/1977
02/08/1977US4007337 Arrangement and method of achieving a dial pulse muting function in a register sender PABX system
01/1977
01/04/1977US4001514 Subscriber digital multiplexing system with time division concentration
12/1976
12/21/1976US3999017 Telephone apparatus
11/1976
11/16/1976US3992591 Telephone line battery boost circuit
11/09/1976US3991278 Line protection switching system
10/1976
10/12/1976US3985974 Power fail monitor and transfer circuit
08/1976
08/31/1976US3978294 Return answer-supervisory circuit
08/17/1976US3975594 Apparatus utilizing a phantom circuit for connecting additional subscribers to a telecommunication system
06/1976
06/22/1976US3965306 Telephone line transfer circuit
02/1976
02/24/1976US3940570 Apparatus for combining a central telephone trunk line with a customer telephone trunk line
02/03/1976US3936614 PBX ground start trunk interface for station carrier systems
01/1976
01/20/1976US3934089 Automatic disconnect circuit for subscriber carrier telephone system
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