Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 3 - Automatic or semi-automatic exchanges
Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881)
01/1985
01/15/1985CA1181158A1 Telephony system with automatic test call generator for remote port groups
01/15/1985CA1181134A1 Communications system and network
01/09/1985EP0130257A1 System and method for the transmission of messages to a subscriber's set through a subscriber's line connected to it
01/08/1985US4493073 Maintenance of stored program controlled switching systems
01/08/1985US4492822 Telephone hold circuit with improved self-limiting amplifier for injecting an audio signal during hold conditions
01/08/1985US4492821 Subscriber connection circuit
01/02/1985CA1180387A Test system for locating breaks and short circuits in a two-lead line
12/1984
12/27/1984CA1180140A Electronic tone ringer
12/27/1984CA1180086A Maintenance termination unit
12/25/1984US4490581 For use in a telephone switching system
12/20/1984WO1984005009A1 Method and apparatus for the connection of a closed ring through a telephone exchange
12/20/1984WO1984005004A1 Test set
12/18/1984US4489222 Telephone line interface
12/18/1984US4489221 Telephone line/subscriber equipment disconnect apparatus
12/18/1984US4489220 In an automatic utility meter reading system
12/12/1984EP0127656A1 A telephone switching arrangement.
12/11/1984US4488291 Circuit arrangement for setting up a conference call
12/11/1984US4488287 Combining and splitting of voice and data from multiple terminal sources and electronic PABX for same
12/11/1984US4488013 Telephone pedestal encapsulating splice housing
12/11/1984US4488009 Compact telephone unit with a plug-in module
12/11/1984US4488008 Telephone network interface device
12/06/1984WO1984004857A1 Ringing signal generator
12/05/1984EP0127137A2 Process for determining the loop condition of a subscriber line
12/05/1984EP0126768A1 A memory cartridge for connection to a telephone switching arrangement.
12/04/1984US4486879 Method and apparatus for mixing low-frequency signals transmitted via different time slots towards the same telephone receiver set
12/04/1984US4486878 Digital telephone exchange with means for processing packet-switched data
12/04/1984US4486627 For testing a transmission line
12/04/1984US4486626 Method of and system for limiting access to a group of telephone trunks
11/1984
11/28/1984EP0126533A1 Test instrument with flexibly connected head
11/27/1984US4485469 Time slot interchanger
11/27/1984US4485274 Sharing an automatic dialer among plural communication channels
11/27/1984US4485271 Remotely actuable line disconnect device
11/23/1984EP0086810A4 Wideband switching architecture.
11/21/1984EP0125279A1 Acd management information system.
11/20/1984US4484105 Circuit for selectively exciting one of a pair of light emitting diodes
11/20/1984US4484031 Interface circuit for a telephone system
11/20/1984US4484030 Method and apparatus for identifying faulty communications circuits
11/13/1984US4482998 Method and apparatus for improving the quality of communication in a digital conference arrangement
11/13/1984US4482997 Arrangement for reducing clipping in a digital conference arrangement
11/13/1984US4482786 Memory dialer system for use with plural telephones and having provision for stacking more than one user
11/13/1984CA1177983A1 On-hook/off-hook detector circuit
11/13/1984CA1177982A2 Link card circuit for electronic key telephone system
11/13/1984CA1177981A2 Page card circuit for electronic key telephone system
11/13/1984CA1177980A2 Line card circuit for electronic key telephone system
11/07/1984EP0123890A2 Method for the assignment of connection data to telephone subscriber's stations
11/06/1984USRE31728 Test set
11/06/1984US4481624 Linear time division multiplexed conferencer
11/06/1984US4481384 Voice recognizing telephone call denial system
11/06/1984US4481383 Communication system recording arrangement
10/1984
10/31/1984EP0123459A1 Loop test circuit
10/31/1984EP0123243A2 Testable coder and decoder apparatus
10/30/1984US4480251 Apparatus to monitor electrical cables, including splice joints and the like, for the ingress of moisture
10/30/1984US4480152 Methods and apparatus for protecting line relay contacts in a telephone switching system
10/24/1984EP0122852A1 Modulating relay, particularly for telecommunication equipment
10/24/1984EP0122354A2 Telephone exchange
10/23/1984US4479212 Conference circuit
10/23/1984US4479211 Method and apparatus for controlling ports in a digital conference arrangement
10/23/1984US4479195 Data conference system
10/23/1984CA1176768A1 Emergency device for subscriber terminal
10/23/1984CA1176751A1 Digital temperature effect generator
10/23/1984CA1176738A1 Microprocessor control circuit
10/17/1984EP0121926A1 Circuit arrangement with automatic subscriber line supervision
10/17/1984EP0121865A2 Circuit arrangement for telecommunication installations, especially for telephone exchanges comprising information processors and devices for overload control
10/16/1984US4477900 Digital communications system
10/16/1984US4477897 Linear time division multiplexed conferencer
10/16/1984US4477807 Radio pager with display device
10/16/1984US4477696 Conference system for telephony
10/11/1984WO1984003977A1 A self routing steering network
10/10/1984EP0121291A2 Method of and apparatus for voice communication storage and forwarding with simultaneous access to multiple users
10/10/1984EP0121239A2 Circuit arrangement for telecommunication installations, especially for telephone exchanges comprising information processors and devices for overload control
10/10/1984EP0121238A2 Circuit arrangement for telecommunication installations, especially for telephone exchanges comprising information processors and devices for overload control
10/10/1984EP0121237A2 Circuit arrangement for telecommunication installations, especially for telephone exchanges comprising information processors and devices for overload control
10/10/1984EP0121236A2 Circuit arrangement for telecommunication installations, especially for telephone exchanges comprising information processors and devices for overload control
10/09/1984US4476349 Call message service
10/09/1984CA1175965A1 Telephone lines status sensor
10/03/1984EP0120718A1 Multi-channel access (MCA) radio telephone system
10/03/1984EP0120552A1 Conference bridge
10/03/1984EP0120459A2 Circuit arrangement for a small PBX with a switching device with electronic switching points
10/03/1984EP0120324A2 Circuit arrangement for an automatic telephone exchange with "hands free" phones facility
10/02/1984US4475190 Method and apparatus for controlling ports in a digital conference arrangement
10/02/1984US4475189 Automatic interactive conference arrangement
10/02/1984US4475187 Broad band exchange system to minimize crosstalk using threshold value multiplex circuits
10/02/1984US4475009 Method and device for remotely controlling telephone call forwarding
10/02/1984CA1175587A1 Overvoltage protection for a line circuit
10/02/1984CA1175501A1 Arrangement for exchanging signals between separated circuit arrangements
09/1984
09/26/1984EP0119843A2 A system for linking channel group in digital communication network
09/26/1984EP0119588A2 Integrated communication system and method of establishing videotelephone links in the same
09/25/1984US4473719 Switchhook status detector
09/19/1984EP0118545A1 Pulse width modulated telephone line interface
09/19/1984EP0118512A1 Automatic audience survey system
09/19/1984EP0118510A1 Data conference system
09/12/1984EP0118111A2 Method of detecting the loop state of a subschriber junction line
09/05/1984EP0117513A1 Operation method for a memory-controlled electronic switching system with central controller
09/05/1984EP0117362A2 Broad band network system
09/04/1984CA1173945A1 Apparatus for switching calls to remotely located port groups in a telephone switching system
09/04/1984CA1173943A1 Semiconductor crosspoint linearizing arrangement
09/04/1984CA1173942A1 Maintenance processing apparatus for remote port units in a telephone switching system
08/1984
08/30/1984WO1984003408A1 Method and circuitry for encoding telephone ringing signals
08/28/1984US4468541 Terminal equipment ring/ding suppression circuit
08/28/1984US4468528 Methods and apparatus for providing enhanced announcements in a telephone system
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