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)
08/1984
08/22/1984EP0116296A1 Method and device for signalling between picture phone sets at an existing telephone link
08/22/1984EP0116291A2 Ring trip detection system
08/21/1984US4467149 Compensation method and apparatus for use with nonideal test access lines
08/21/1984US4467147 Switching network for interactive access and testing of subscriber loops
08/21/1984US4467143 Telephone conference amplifiers, and telephone conference bridges incorporating the same
08/21/1984CA1173182A1 Programmable line circuit
08/14/1984US4466095 Speech path control system
08/14/1984US4466094 Data capture arrangement for a conference circuit
08/14/1984US4466093 Time shared conference arrangement
08/14/1984US4466092 Test data insertion arrangement for a conference circuit
08/14/1984CA1172737A1 Analog subscriber/trunk module with shared ringing source and ring trip
08/07/1984USRE31643 Hold circuit for telephone system
08/07/1984US4464621 Test device for and method of locating faults in a two-wire line or for switching two-wire lines
08/07/1984US4464543 In a telecommunication system
07/1984
07/31/1984CA1171987A1 Telephone tactile alert system
07/31/1984CA1171945A1 Voice recognizing telephone call denial system
07/31/1984CA1171922A1 Solid state relay
07/17/1984US4460807 For use in a communication system
07/11/1984EP0112967A1 Call interceptor
07/10/1984US4459437 Test system for locating breaks and short circuits in a two-lead line
07/10/1984US4459436 Programmable tester for measuring network characteristics
07/10/1984US4459434 Home telephone exchange
07/05/1984WO1984002625A1 Method of detecting hazardous line voltages over a two-wire line
07/04/1984EP0112734A1 Arrangement for the interconnection of transmission lines, especially telephone lines, using differential amplifiers
07/04/1984EP0112731A2 Subscriber line interface circuit
07/04/1984EP0112678A1 A telecommunications system
07/03/1984US4458113 Conductor pair identifier apparatus
07/03/1984US4458112 Floating subscriber loop interface circuit
07/03/1984CA1170379A1 Digital conference time slot interchanger
06/1984
06/27/1984EP0111832A1 Circuit arrangement for fault localisation in a digital telephone subscriber line
06/26/1984US4456940 Voltage controlled transient protection unit
06/26/1984US4456792 Voice switching arrangement for telephone conferencing
06/26/1984US4456791 Off-hook detector with reduced sensitivity to common mode
06/26/1984US4456789 Audio teleconferencing
06/26/1984US4456788 Telecommunication trunk circuit reporter and advisor
06/26/1984CA1169984A1 Multimessage automatic telephone polling methods and apparatus
06/20/1984EP0111406A1 Transmission integrity arrangement and method
06/20/1984EP0110964A1 Automatic interactive conference arrangement.
06/20/1984EP0110933A1 Apparatus for through-connection testing in a digital telecommunication network.
06/19/1984US4455645 Back-up control system implemented with a redundancy scheme for protection against failure
06/19/1984US4455456 Digital supervisory circuit for a telephone system
06/19/1984US4455455 Internodal conference call administrator
06/19/1984CA1169597A1 Home communications and control system
06/13/1984EP0110444A1 Ringing signal generator
06/13/1984EP0110360A2 Circuit arrangement for composing and separating speech and data during the transmission in a digital switching network
06/12/1984US4454477 Loop current detector with threshold setting impedance
06/12/1984US4454388 Arrangement for subscriber line verification and ring testing
06/12/1984US4454385 Latching relay hold release circuit for a telephone instrument
06/07/1984WO1984002207A1 A memory cartridge for connection to a telephone switching arrangement
06/07/1984WO1984002206A1 A telephone switching arrangement
06/05/1984US4453210 Multiprocessor information processing system having fault detection function based on periodic supervision of updated fault supervising codes
06/05/1984US4453049 Arrangement for single line testing
06/05/1984US4453048 Arrangement for subscriber line ring testing
06/05/1984CA1168774A1 Key telephone hold arrangement
06/05/1984CA1168737A1 Time division switching system
06/05/1984CA1168707A1 Apparatus to monitor electrical cables, including splice joints and the like for the ingress of moisture
05/1984
05/30/1984EP0109705A1 Subscriber circuit for a telephone network
05/30/1984EP0109432A1 Call completion circuit and method
05/29/1984US4451708 Spare subscriber terminal apparatus
05/29/1984US4451706 Telephone substation transmitter muting circuit
05/29/1984US4451705 Call completion circuit and method
05/29/1984US4451704 Switching system auxiliary line transfer circuit
05/29/1984US4451703 All electronic interface for telephony system
05/29/1984US4451700 Automatic audience survey system
05/29/1984CA1168333A1 Apparatus for controlling and indicating the integrity of the connection of telephone subscribers to a switching system
05/23/1984EP0109260A2 Telephone conference system
05/15/1984US4449238 Voice-actuated switching system
05/15/1984US4449217 PCM Communication system and method of operation
05/15/1984US4449017 ACD Combined handset and headset arrangement
05/10/1984WO1984001871A1 Acd management information system
05/08/1984US4447679 Subscriber line testing system
05/08/1984US4447675 Ring-trip detector
05/08/1984US4447674 Electronic hold release circuit
05/01/1984US4446554 Arrangement for multiple custom calling
05/01/1984US4446553 Arrangement for multiple custom calling
05/01/1984US4446341 Mechanized testing of subscriber facilities
05/01/1984US4446340 Customer premises loop test unit powered from the normal central office power source
05/01/1984US4446339 Rotary dial decoder
05/01/1984US4446338 Telephone lines status sensor
05/01/1984US4446337 Method and apparatus for revertive automatic intercept message delivery in a telephone system
05/01/1984US4446336 Method for recording and updating stored messages in an announcement system
05/01/1984CA1166777A1 Home telephone exchange
05/01/1984CA1166776A1 Restricted access line circuit for a communications system
05/01/1984CA1166729A1 Logic device for alarm pretreatment
04/1984
04/25/1984EP0106575A2 Electronic audio communication system with user controlled message address
04/25/1984EP0106247A1 Telephone system
04/25/1984EP0105916A1 Method and apparatus for identifying faulty communications circuits.
04/24/1984US4445212 Arrangement for multiple custom calling
04/24/1984US4445211 Arrangement for multiple custom calling
04/24/1984US4445148 Automatic telephone answering apparatus
04/24/1984US4445007 Remote testing of subscriber line interface circuits
04/24/1984US4445003 Improved connection arrangement for connecting series and shunt utilization circuit to a communications channel
04/24/1984US4445001 Circuit arrangement for identifying telephone subscribers
04/24/1984CA1166371A1 Service-integrated communication transmission and exchange system
04/24/1984CA1166365A1 Distributed digital conferencing system
04/18/1984EP0105441A1 Telephone switching system for public or private telephone networks with at least one central dial information recording and processing device
04/17/1984US4443669 Subscriber connection circuit
04/17/1984US4443665 Privacy and hold circuit for telephone
04/17/1984CA1165915A1 Programmable ring signal generator
04/17/1984CA1165894A1 Computer control systems
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