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)
02/1982
02/03/1982EP0045067A1 Time division switching system
02/02/1982US4314328 Information extractor for the selective visualization of data stored in a monitoring memory
02/02/1982US4314110 System for the testing of telephone switching systems
02/02/1982CA1117636A1 Telephone exchange
01/1982
01/26/1982US4313036 Distributed CBX system employing packet network
01/26/1982US4313035 Method of providing person locator service
01/26/1982US4313034 Connecting circuit for a telephone line
01/26/1982US4313033 Apparatus and method for digital combination of delta modulated data
01/26/1982CA1117231A1 Signal processing apparatus for subscriber circuits
01/21/1982WO1982000232A1 A process and system for error detection in a computer-controlled telephone exchange
01/19/1982US4311882 Method of and arrangement for testing traffic routes in telecommunication networks
01/19/1982US4311880 Key telephone hold arrangement
01/19/1982US4311875 Interface system isolating a subscriber subset from a telephone switching system
01/19/1982CA1116733A1 Interoffice callback arrangement
01/12/1982US4310728 Ringing device for a private automatic branch exchange
01/12/1982US4310726 Method of identifying a calling station at a call terminating facility
01/12/1982US4310724 Current detector circuit
01/12/1982CA1116329A1 Loop, dial pulse and ring trip detection circuit
01/06/1982EP0042861A1 Automated conversation system
01/05/1982US4309578 Telephone ringer load simulator
01/05/1982US4309572 Call processing system with an operator assistance in a telephone switching system
12/1981
12/29/1981CA1115438A1 Audio teleconferencing
12/23/1981EP0042133A1 Service-integrated message transmission and communication system
12/22/1981US4307454 Arrangement preventing multiple connections to peripheral circuits
12/22/1981CA1114971A1 Telephone multiresponder apparatus
12/22/1981CA1114970A1 Pulse rejection and duration correction circuit
12/22/1981CA1114934A1 Dialed number to function translator for telecommunications switching system control complex
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
12/15/1981US4306295 Arrangement for measuring the ratio between a number of events occurring after each other in a first and a second series of events
12/15/1981CA1114536A1 Ringing generator
12/15/1981CA1114512A1 Arrangement for measuring the ratio between a number of events occurring after each other in a first and a second series of events
12/15/1981CA1114482A1 Attendant console complex
12/09/1981EP0041262A1 Programmable telephone-traffic measuring equipment
12/09/1981EP0041195A1 Improved paging arrangement
12/08/1981US4305149 Conferencing method and apparatus with multiplexed analog signals
12/08/1981US4304966 PBX Field display
12/08/1981CA1114082A1 Digital conference circuit
12/01/1981US4303804 Telephone-conferencing apparatus and method having line location
12/01/1981CA1113575A1 Check circuit for synchronized clocks
11/1981
11/24/1981US4302843 Method and apparatus for measuring transmission characteristics of a test object during communication gaps
11/24/1981US4302836 Monitoring circuit for time-division switching network
11/24/1981US4302632 Digitally-controlled telephone answering switching system
11/17/1981US4301531 Three-party conference circuit for digital time-division-multiplex communication systems
11/17/1981US4301334 Telecommunication subscriber line access circuit with ground key and insulation fault indication
11/17/1981CA1112744A1 Audio teleconferencing
11/10/1981US4300024 Technique for measuring a duration of signaling pulses in a telephone circuit
11/10/1981CA1112385A1 Compensation of transmission losses in a telephone system
11/10/1981CA1112384A1 Loop to ground start circuit
11/10/1981CA1112343A1 Conversational telephone call distributor
11/03/1981US4298775 Microprocessor controlled telephone set
11/03/1981US4298774 Call waiting signal arrangement
10/1981
10/28/1981EP0038506A2 Control system for electro-optical display elements, especially of a telephonic subset
10/27/1981US4297536 Self-adjusting hybrid network
10/27/1981US4297531 Circuit for suppressing noise influences in the evaluation of signal states on transmission lines
10/21/1981EP0038147A1 Improvements in or relating to computer control systems
10/15/1981WO1981002959A1 Portable telephone line test set
10/14/1981EP0037540A2 Method and circuit for feeding call signals to telecommunication lines, especially in telephone exchanges
10/13/1981US4295220 Clock check circuits using delayed signals
10/13/1981US4295008 Telephone-conferencing apparatus and method having response tallying
10/13/1981US4295007 Line identifier for switchboards
10/13/1981CA1110746A1 Finite storage-time queue
10/07/1981EP0037111A1 Circuit for generating ringing signals for telecommunication lines
10/06/1981US4293946 Trilateral duplex path conferencing system with broadcast capability
10/01/1981WO1981002824A1 Memory accessing system
10/01/1981WO1981002823A1 Automatic calling methods and apparatus
09/1981
09/30/1981EP0036619A1 Circuit arrangement for a telephone exchange, particularly for a private automatic branch exchange, with a message store for recalling
09/29/1981US4292480 Method and apparatus for locating telephones
09/22/1981US4291299 Analog to digital converter using timed level changes
09/22/1981US4291199 Communication system tracking arrangement
09/15/1981US4289934 Integrated automatic call distribution facility and PBX system
09/15/1981US4289932 Conferencing communications system
09/15/1981CA1109171A1 Supply arrangement for a line circuit
09/15/1981CA1109170A1 Arrangement for measuring the line condition of a subscriber's line circuit by means of a measuring resistor
09/08/1981US4288871 Digital loop conferencing signal correction arrangement
09/08/1981US4288662 Circuit arrangement for telephone exchange systems, especially subscriber extension station installations, with additional data traffic, for example with teleprinter equipment
09/08/1981CA1108789A1 Key telephone unit protective coupler
09/02/1981EP0034776A1 Diagnostic circuit for PCM connection networks
09/01/1981US4287591 Communications transmission system
09/01/1981US4287393 Transmission bridge for a subscriber's circuit
09/01/1981CA1108325A1 Telecommunications system
08/1981
08/28/1981EP0026187A4 Communication system tracking arrangement.
08/26/1981EP0034514A1 Time division switching installation for lines carrying voice and data packets
08/26/1981EP0034384A1 Arrangement for applying a ringing voltage to a subscriber's line
08/26/1981EP0034339A1 Telephone circuit for off-hook detection during ringing
08/26/1981EP0034308A1 Method and circuit for conference operation in PCM time division multiplex telecommunication installations
08/25/1981US4286114 Two-wire resistance bridges for private line circuits
08/19/1981EP0033933A2 Process for feeding audible tones into conference communications
08/19/1981EP0033858A1 Circuit arrangement for measuring the electric characteristics of user telephone lines
08/19/1981EP0033744A1 Voice controlled switching system
08/18/1981US4284854 Universal signal generator for generating telephone system high level signals
08/18/1981US4284853 Telecommunication subscriber line access circuit with ground key indication and a device for call signal generation
08/18/1981US4284851 Arrangement for frustrating fraudulent telephone calls
08/11/1981US4283603 On-hook/off-hook status check circuit
08/11/1981CA1106986A1 Telephone instrument connection block with remotely actuated line test
08/11/1981CA1106766A1 Simultaneous interpretation apparatus
08/04/1981US4282408 On-hook/off-hook detector circuit
08/04/1981US4282407 Telephone loop resistance detector
08/04/1981US4282399 Shared maintenance terminal system
08/04/1981CA1106513A1 Telephone signalling test system
07/1981
07/28/1981USRE30692 Method and apparatus for measuring telephone line characteristics
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