Patents
Sitemap › H04 - Electric communication technique › H04M - Telephonic communication › H04M 9 - Arrangements for interconnection not involving centralised switching
Patents for H04M 9 - Arrangements for interconnection not involving centralised switching (8,105)
10/1991
10/23/1991EP0452629A2 Telephone apparatus capable of setting card unit therein as electronic notebook
10/22/1991US5060257 Videotex terminal for receiving telecopies
10/22/1991CA1291282C Loudspeaking telephone with a frequency shifting circuit
10/15/1991US5058153 Noise mitigation and mode switching in communications terminals such as telephones
10/15/1991CA1290871C Method for terminating a telephone call by voice command
10/13/1991WO1991016796A1 Private telephone system with simplified command feature
10/02/1991DE4009820A1 Avoiding acoustic feedback in communication equipment - using microphone in conjunction with signal processing equipment to determine optimum of equipment
10/01/1991US5054061 Hands-free telephone
09/1991
09/25/1991CN2085583U Practical intercom and telephone expander
09/18/1991CN2085119U Two-way wire dialogue door bell
09/17/1991US5050160 Training method for an echo canceller for use in a voice conference system
09/11/1991EP0445375A1 Method of in-house voice and data communication via the home power distribution network
09/10/1991US5048082 Voice direction recognition in a digital telephone station
09/10/1991US5048080 Control and interface apparatus for telephone systems
09/10/1991US5048076 Control apparatus for an automated telephone attendant
09/10/1991CA2037557A1 Method for in-house voice and data communication through the in-house power supply
09/03/1991US5046086 Page-mapped multi-line telephone communication system
09/03/1991US5046080 Video codec including pipelined processing elements
08/1991
08/29/1991DE4039388A1 Key communication system with central computer control - has pair of associated terminals with mutual dependence for certain communication modes
08/29/1991DE4006048A1 Communication system interconnecting subscriber terminals - has terminal of one subscriber serviceable independently of state of terminal of other subscriber
08/28/1991EP0443547A2 Sub-band acoustic echo canceller
08/27/1991CA1288187C Apparatus and method for hands free telephonic communication
08/27/1991CA1288186C Device for performing the "hands-free" function in a telephone set association the gain switching and echo suppression functions
08/27/1991CA1288185C Apparatus for controlling key telephone station set in key telephone system
08/21/1991WO1991013508A1 A method for active feedback suppression
08/21/1991CN1013632B Baseband data transmission method and computer local area net in telephone exchange
08/20/1991US5042065 Resetting circuit in a key-telephone system
08/20/1991CA1287887C Speakerphone using digitally compressed audio to detect acoustic feedback
08/17/1991WO1991012683A1 Speaking device having hand-free conversational function
08/13/1991US5040209 Telephone ringing monitoring and control system
08/13/1991US5040207 Two-telephone intercom
08/13/1991US5040206 Communication apparatus having driving mechanism and speaker-phone
08/13/1991CA1287679C Controlling key-system groups from a distributed control switching system
08/07/1991CN2082494U Automatic transferring device of portraiture and telephone
08/07/1991CN1013466B Digital key telephone system
08/02/1991WO1991011873A1 Speakerphone for cellular telephones with howl prevention
07/1991
07/31/1991WO1991011888A1 Key telephone device
07/24/1991CN2081617U Mobile telephone set
07/24/1991CN1053337A Echo canceller
07/16/1991US5033081 Key telephone system
07/16/1991US5033080 Method and apparatus for identifying the source of page communication in a party-line intercom paging system
07/11/1991WO1991011060A1 Echo canceller
07/11/1991CA2048634A1 Echo canceller
07/09/1991US5031210 Telephone apparatus
07/03/1991EP0435032A2 Conference system
07/02/1991CA1285670C Control system for a plurality of telephone sets
06/1991
06/26/1991EP0433782A2 Conference network
06/25/1991US5027393 Voice conference system using echo cancellers
06/25/1991US5027391 Call management system
06/25/1991US5027347 Intercom system
06/25/1991US5027345 Digital key telephone system
06/25/1991US5027341 Station line switching control system
06/18/1991US5025441 Key telephone system
06/05/1991EP0429571A1 Device for telecommunication systems
06/04/1991US5021783 Method for operating an apparatus for facilitating communications
05/1991
05/28/1991US5020098 Telephone conferencing arrangement
05/14/1991US5016271 Echo canceler-suppressor speakerphone
05/07/1991US5014347 Field telephone system
05/07/1991US5014302 Telephone
05/07/1991US5014294 Speakerphone for cellular telephones with howl prevention, detection, elimination and determination
05/07/1991CA1283986C Hold detecting and control circuit for a key telephone system
04/1991
04/24/1991EP0423537A2 Method for the automatic switching of the speech direction and circuit for implementing the method
04/23/1991US5010570 Method for active feedback suppression
04/09/1991US5007046 Computer controlled adaptive speakerphone
04/02/1991CA1282511C Voice control circuit for a communication terminal
04/02/1991CA1282506C Multiplexed data channel controlled telephone system
04/02/1991CA1282481C Communication system dynamic conferencer circuit
03/1991
03/20/1991EP0417425A1 Method for transmitting information between several user stations and user station for carrying out the method
03/20/1991CN1012121B Volume range control circuit
03/12/1991CA1281399C Electronic telephone exchange and method of connecting ports ofthe exchange
03/07/1991WO1991003116A1 Device for treating echoes, particularly acoustic echoes, in a telephone line
03/06/1991EP0415031A2 Circuit arrangement for suppression of electrical and/or acoustical feedback
03/05/1991US4998275 Multi-line telephone communications system
03/05/1991US4998273 Telephone line called number recognizer
03/05/1991US4998241 Echo canceller
03/05/1991CA1281112C Communication system having automatic call route selection
02/1991
02/26/1991US4996709 Intercom telephone
02/26/1991US4996708 Key telephone system adapted to respond to information stored in a portable outpulser
02/20/1991EP0413641A1 Arrangement for echoprocessing, especially acoustic, in a telephone line
02/19/1991US4995070 Electronic key telephone set with function operation test function and method of controlling the same
02/19/1991US4995034 Method of integrating one or more accessory function modules in telecommunications systems and access circuit for use therewith
02/13/1991CN2071406U Liaison machine for sentry post
02/05/1991US4991167 Triple cone
02/05/1991US4991166 Echo reduction circuit
01/1991
01/30/1991EP0410698A2 Hands-free telephone
01/30/1991EP0267267A4 Hospital signaling and communications system
01/29/1991US4989242 Control device for a hand-free alternate operating telephone set
01/29/1991US4988209 Telephone agent management information system
01/23/1991CN2070065U Multichannel internal telephonic communication system
01/22/1991US4987573 Telephone system digital channel bank interface
01/22/1991CA1279415C Telephone line carrier system
01/17/1991DE3930278C1 Establishing stereo telephone connection - using integrated digital communication system for coualing two useful data channels and signalling channel
01/15/1991US4985915 Method for interfacing between a key-phone system and a key-phone subscriber
01/08/1991US4984265 Device for forming the hands-free function in a telephone set, associating the gain switching and echo suppression functions
01/08/1991US4984263 Key-phone system
01/02/1991CN1048292A 电话机 Phone
01/01/1991US4982427 Integrated circuit for telephone set with signal envelope detector
01/01/1991US4982425 Hands-free telephone
12/1990
12/27/1990EP0404084A1 Telephone apparatus
12/27/1990EP0403923A1 Telephone device for connection to several telephone lines
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