| Patents for H04M 19 - Current supply arrangements for telephone systems (7,475) |
|---|
| 12/20/1977 | US4064377 Electronic hybrid and hybrid repeater |
| 11/01/1977 | US4056693 Voltage and current controlled converter for telephone ringing |
| 11/01/1977 | US4056691 Telephone subscriber line circuit |
| 11/01/1977 | US4056689 Telephone subscriber line circuit |
| 11/01/1977 | US4056688 Telephone range extender with gain |
| 11/01/1977 | US4056687 Decoupling control arrangement for auxiliary circuits coupled to telephone lines |
| 10/18/1977 | US4054941 Range extender with gain |
| 10/11/1977 | US4053722 Solid state two-wire/four-wire converter with common battery |
| 10/11/1977 | US4053717 Cordless telephone |
| 09/20/1977 | US4049928 Self-adjusting voice frequency repeater |
| 09/13/1977 | US4048552 Digitally regulated inverter |
| 09/06/1977 | US4046970 Ringing detector for telephone circuits |
| 09/06/1977 | US4046969 Dial pulse repeating line circuit using miniature line transformer |
| 09/06/1977 | US4046968 Integrable line circuit for use with miniature line transformer |
| 09/06/1977 | US4046967 Line circuit using miniature line transformer |
| 08/16/1977 | US4042786 Telephone ringer circuit |
| 08/09/1977 | US4041252 Four-wire hybrid with dc sourcing capability |
| 08/02/1977 | US4039766 Electric two-to-four wire conversion circuit for use in telephone systems |
| 08/02/1977 | US4039760 Cordless telephone system |
| 07/19/1977 | US4037117 Peak shut-off electronic switch |
| 07/12/1977 | US4035586 Current supply system for terminal devices |
| 07/05/1977 | US4034166 Transmission networks for telephone system |
| 06/21/1977 | US4031332 Telephone ringer insolator |
| 05/31/1977 | US4027235 Direct current compensation circuit with current threshold detection |
| 05/31/1977 | US4027224 Post-regulated switching regulator circuit |
| 05/24/1977 | US4025729 Telephone ringing control circuits |
| 05/24/1977 | US4025727 Balanced tone application system |
| 05/17/1977 | US4024351 Telephone line battery boost circuit |
| 05/10/1977 | US4022985 Key telephone system with a common push-button sender system |
| 05/10/1977 | US4022980 Ring trip detector |
| 05/03/1977 | US4021617 Telephone ringer isolator |
| 04/12/1977 | USRE29183 Telephone range expander |
| 03/29/1977 | US4015091 Telephone ringing generators |
| 03/15/1977 | US4012702 Chime generating circuit |
| 03/08/1977 | US4011410 Communication system interface circuits |
| 03/01/1977 | US4010329 Crescendo control of signalling devices |
| 02/08/1977 | US4007335 Telephone line battery feed circuit |
| 02/01/1977 | US4006316 Code-controlled detection and function actuating system |
| 01/18/1977 | US4004109 Hybrid circuit |
| 01/18/1977 | US4004104 System for feeding in continuous current to a telephone line |
| 01/11/1977 | US4002853 Visual ring indicator |
| 01/11/1977 | US4002838 Telephone ringing control circuits |
| 01/04/1977 | US4001708 Code-controlled ringer attachment for telephones including a-peak-to-peak gain controlled amplifier |
| 01/04/1977 | US4001516 Apparatus for feeding and controlling ringing currents in telecommunication systems |
| 01/04/1977 | US4001515 Interfacing unit for telephone networks |
| 12/14/1976 | US3997733 Intrinsically safe communication systems |
| 11/23/1976 | US3993880 Resistive battery feed for line circuits |
| 11/16/1976 | US3992591 Telephone line battery boost circuit |
| 10/12/1976 | US3986097 Bilateral direct current converters |
| 10/12/1976 | US3985976 Audio frequency signalling systems for telephone systems |
| 10/05/1976 | US3984761 Line powered voltage regulator |
| 09/14/1976 | US3980837 Apparatus for pulsing in telephone sets |
| 08/31/1976 | US3978391 Direct current stabilizing device |
| 08/17/1976 | US3975594 Apparatus utilizing a phantom circuit for connecting additional subscribers to a telecommunication system |
| 08/03/1976 | US3973082 Electronic telephone subscriber set with voltage controlled variable shunt |
| 07/20/1976 | US3970805 Active hybrid circuit |
| 07/20/1976 | US3970801 Dialing apparatus for a portable radio telephone |
| 07/13/1976 | US3969591 Circuit for preventing impulse generation by operating a hook switch in a telephone set |
| 07/06/1976 | US3968333 Battery charger control circuit for telephone transmission systems |
| 06/22/1976 | US3965447 Synthetic reactor circuit |
| 06/22/1976 | US3965307 Electronic tone ringer |
| 06/15/1976 | US3963974 Power supply circuit |
| 05/25/1976 | US3959718 Direct current supply source |
| 05/25/1976 | US3959604 Digital calling signal tone generating circuitry |
| 05/11/1976 | US3956596 Circuit arrangements in telephone apparatus |
| 05/04/1976 | US3955052 Subscriber unit particularly useful for time-division-multiplex system |
| 04/27/1976 | US3953683 Interrupter for telephone systems |
| 03/23/1976 | US3946164 Precise tone signal generator |
| 03/09/1976 | US3943432 Electronic feeding bridge |
| 03/02/1976 | US3941941 Relayless switching circuit for application of ringing signals |
| 03/02/1976 | US3941939 Electronic ring trip circuit |
| 02/24/1976 | US3940572 Power supply for key telephone system |
| 02/17/1976 | US3939311 Muting circuit for subscribers telephone |
| 02/03/1976 | US3936617 Code-controlled ringer attachment for telephones |
| 01/20/1976 | US3934089 Automatic disconnect circuit for subscriber carrier telephone system |