H04M 3 - Automatic or semi-automatic exchanges

Patents for H04M 3 - Automatic or semi-automatic exchanges (99,881)
02/1977
02/22/1977	US4009346 Distributional activity compression
02/22/1977	US4009345 External management of satellite linked exchange network
02/15/1977	US4008376 Loudspeaking teleconferencing circuit
02/08/1977	US4007338 Switching and transmission technique using a method and arrangement of channel allocation for providing conferencing
02/01/1977	US4006307 Impulse noise suppression circuit
01/1977
01/25/1977	US4005491 Dampened transducer support apparatus for message announcing system
01/18/1977	US4004107 Telephone circuit to eliminate use of a hold button
01/11/1977	US4002861 Protector module test set
01/11/1977	US4002857 Telephone circuit to eliminate use of a hold button
01/11/1977	US4002842 Time multiplex loop telecommunication system
01/04/1977	US4001559 Programmable measuring
01/04/1977	US4001520 Hold circuit for telephones
01/04/1977	US4001517 Direct station selection hold arrangement
01/04/1977	US4001508 Message communication system for telephone lines
12/1976
12/28/1976	US4000380 Toll restrictor for touch type digit selector
12/28/1976	US4000377 Digital compound conference system
12/28/1976	US4000375 Automatic call transfer circuit for a plurality of telephones
12/21/1976	US3999017 Telephone apparatus
12/14/1976	US3997735 Telephone station make-busy circuit
12/14/1976	US3997734 Telephone hold attachment
12/14/1976	US3997730 Time division conference circuit
12/07/1976	US3996425 Call denial circuit
11/1976
11/30/1976	US3995118 Call processing restoration arrangement for a telephone switching system
11/09/1976	US3991282 Multi station telephone switching system
11/09/1976	US3991281 Key telephone monobus conference arrangement
11/09/1976	US3991280 Monobus variable resistance transmission circuit
11/09/1976	US3991279 Monobus interface circuit
11/02/1976	US3990050 Computer controlled automatic response system
11/02/1976	US3989899 Telephone scheduling system
10/1976
10/19/1976	US3987252 Computer controlled telephone answering system
10/12/1976	US3986120 Telephone system comprising a satellite
10/12/1976	US3985975 Holographic telephone switching system
10/12/1976	US3985959 Key telephone system for subscribers
10/05/1976	US3984643 Method and apparatus for establishing a plurality of simultaneous conferences in a PCM switching system
09/1976
09/28/1976	US3983339 Dynamic speed of answer recorder
09/28/1976	US3983338 Apparatus and method to test the condition of an electrical service line and to determine the presence and/or removal of electrical equipment connected to the line
09/28/1976	US3983332 Conference call circuitry for TDM signal exchange
09/21/1976	US3982232 Traffic usage data gathering apparatus
09/14/1976	US3980840 Conductor identification arrangement for a cable restoration system
09/14/1976	US3980839 Maintenance monitor for telephone switching systems
09/14/1976	US3980836 Toll restricting method and apparatus
09/14/1976	US3980831 Data switching system
08/1976
08/24/1976	US3976849 Telephone wiring tester
08/24/1976	US3976841 Electronic time switching telephone system
08/17/1976	US3975597 Call queue release control circuit
08/17/1976	US3975595 Service code conversion
08/17/1976	US3975594 Apparatus utilizing a phantom circuit for connecting additional subscribers to a telecommunication system
08/10/1976	US3974338 Apparatus for automatic message reprogramming of a message announcement system
08/03/1976	US3973090 Telephone number assignment record verification apparatus and method
07/1976
07/27/1976	US3971891 Adaptable time division switch
07/20/1976	US3970797 Digital conference bridge
07/13/1976	US3969594 Automated telephony testing and polling apparatus and system
07/13/1976	US3969589 Telephone switching system having attendant queuing facilities
07/13/1976	US3969587 Selective transmission of prerecorded voice signals to subscribers of time-sharing telecommunication system
06/1976
06/29/1976	US3967075 Attendant board system in a telephone exchange
06/29/1976	US3967070 Memory operation for 3-way communications
06/22/1976	US3965418 Telephone system testing apparatus and techniques utilizing central measuring equipment with a plurality of remote test stations
06/22/1976	US3965304 Intercept arrangement for key telephone systems
05/1976
05/25/1976	US3959605 Circuit for detecting loss of telephone line voltage
05/25/1976	US3959593 Traffic analysis from a scanner using a micro-processor
05/18/1976	US3958084 Conferencing apparatus
04/1976
04/27/1976	US3953682 Loop current detector
04/20/1976	US3952172 Telephone call simulator
04/20/1976	US3951248 Telephone line visual status indication circuit
04/06/1976	US3949176 Method of and apparatus for all busy detection
03/1976
03/30/1976	US3947639 Selective switching apparatus
03/16/1976	US3944758 Talk line multiple communication and test apparatus
03/16/1976	US3944752 Telephone line status indicator
03/09/1976	US3943305 Telephone line control system
03/09/1976	US3943290 Semi-automatic telephone-answering system
03/02/1976	US3941950 Telephone line testing instrument having a supervising capability
02/1976
02/24/1976	US3940739 Alarm reporting system
02/24/1976	US3940564 Time division multiplex system with conference link
02/10/1976	US3937931 Procedure to determine the temporal mean of a quantity to be measured, as a function of its period of operation
02/10/1976	US3937901 Lamp control circuit for key telephone systems
02/10/1976	US3937898 Digital conference bridge
02/03/1976	US3936613 Camp-on detecting system for automatic telephone exchange
01/1976
01/27/1976	US3935396 Key telephone system using time division and space division control
01/20/1976	US3934098 Telephone message transfer circuit
01/13/1976	US3932844 Common control switching system
01/06/1976	US3931478 Telephone intercommunication system provided with a common communication line to which access is guarded

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