| Patents for H04M 1 - Substation equipment, e.g. for use by subscribers (168,223) |
|---|
| 02/01/1977 | US4006312 Sound recording and reproducing machines |
| 02/01/1977 | US4006309 Voice operated relay |
| 01/25/1977 | US4005279 Lockable cover for push button telephones |
| 01/25/1977 | US4005271 Automatic telephone answering and recording apparatus |
| 01/25/1977 | US4005270 Remote control for operating a telephone answering system from a remote point over the telephone line |
| 01/25/1977 | US4005269 Apparatus for interfacing between telephone and wireless communication systems |
| 01/18/1977 | US4004276 Telephone answering machines |
| 01/18/1977 | US4004112 Quickly attachable note pad support accessory for desk telephones |
| 01/11/1977 | US4002860 Transmitting and receiving apparatus |
| 01/11/1977 | US4002855 Push-button telephone attachment |
| 01/11/1977 | US4002852 Electronic telephone network |
| 01/11/1977 | US4002670 Nematic compounds and mixtures |
| 01/04/1977 | US4001506 Home intercom telephone set |
| 12/28/1976 | US4000379 Tone generator |
| 12/21/1976 | US3999049 Synthesizer of multifrequency code signals |
| 12/21/1976 | US3999017 Telephone apparatus |
| 12/21/1976 | US3999016 Automatic telephone answering and message recording apparatus |
| 12/21/1976 | US3998514 Device armed with a terminal for making electrical connection with a conductor |
| 12/14/1976 | US3997740 Pulse train analyzer |
| 12/14/1976 | US3997733 Intrinsically safe communication systems |
| 12/14/1976 | US3997732 Call tracing and identification system |
| 11/30/1976 | US3995217 Method and apparatus for suppressing background noise in a digital telephone system |
| 11/30/1976 | US3995123 Telephone calculator |
| 11/23/1976 | US3993879 Acoustical communications headset |
| 11/23/1976 | US3993877 Automatic dialing equipment |
| 11/23/1976 | US3993876 Automatic dialing apparatus for telephones |
| 11/23/1976 | US3992795 Stick-on telephone number reference list holder for handsets |
| 11/16/1976 | US3992583 Universal flexible acoustic coupler muff system |
| 11/09/1976 | US3991274 Telephone answering system with one responsive circuit for remote playback control |
| 11/02/1976 | US3989902 Alternating current regulator for use with telephone type line |
| 11/02/1976 | US3989901 Optional telephone answering system |
| 10/26/1976 | US3988550 Telephone repertory dialer |
| 10/26/1976 | US3988549 Keyboard type telephone station adapted to transmit dialling pulses and multifrequency signals |
| 10/26/1976 | US3988542 Variable message recorder using a disc without grooves and a single motor to provide both turntable drive and spiral scanning |
| 10/19/1976 | US3987254 Transformerless amplification circuitry for telecommunication system |
| 10/19/1976 | US3987253 Hybrid coupling for telecommunication system |
| 10/12/1976 | US3986119 Emergency communication system |
| 10/12/1976 | US3985972 Telephone call restrictor |
| 10/12/1976 | US3985966 Method and apparatus for generating digital dual frequency signals |
| 10/05/1976 | US3984645 Lightweight headset and retractable cord spool |
| 10/05/1976 | US3984640 Telephone answering device without outgoing message tape |
| 09/21/1976 | US3982079 Touch-to-rotary converter for a telephone instrument |
| 09/21/1976 | US3982078 Line matching circuit for use in a tone pushbutton dialling subscriber's set provided with a tone generator |
| 09/21/1976 | US3982072 Phone aid timing device |
| 09/14/1976 | US3980842 Telephone listening comfort adaptor (TLCA) |
| 09/14/1976 | US3980837 Apparatus for pulsing in telephone sets |
| 09/14/1976 | US3980836 Toll restricting method and apparatus |
| 09/07/1976 | US3979560 Telephone answering system with ring detector |
| 08/31/1976 | US3978295 Circuit arrangement for a tone pushbutton selection telephone subscriber set |
| 08/31/1976 | US3978289 Remote-controlled automatic telephone-answering and message-recording apparatus |
| 08/24/1976 | US3976849 Telephone wiring tester |
| 08/24/1976 | US3976846 Dial device for a telephone set having a function of preventing toll dialing |
| 08/10/1976 | US3974401 System for detecting the transmission direction of a signal on a two-way transmission line |
| 08/10/1976 | US3974344 Electronic speech circuit for a central battery telephone set |
| 08/10/1976 | US3974338 Apparatus for automatic message reprogramming of a message announcement system |
| 08/03/1976 | US3973084 Electric impulse transmitters for telephone instruments |
| 08/03/1976 | US3973083 Rotary dial device for a telephone set |
| 08/03/1976 | US3973082 Electronic telephone subscriber set with voltage controlled variable shunt |
| 07/27/1976 | US3971901 Communications headset with reversible mounting means |
| 07/27/1976 | US3971900 Communications headset with rotatable and tiltable electrical connector |
| 07/27/1976 | US3971896 Two-tone generator using switching transistors in LC resonant circuits controlled by push-button |
| 07/20/1976 | US3970792 Adjustable mounting structure for video telephone unit |
| 07/13/1976 | US3969721 Light emitting diode indicator assembly for a multiple pushbutton array |
| 07/13/1976 | US3969592 Pushbutton-controlled call-number selector for dial-equipped telephone |
| 07/13/1976 | US3969591 Circuit for preventing impulse generation by operating a hook switch in a telephone set |
| 06/29/1976 | US3967076 Call denial circuit for key telephone systems |
| 06/29/1976 | US3967068 Automatic telephone monitoring system |
| 06/22/1976 | US3965310 Apparatus for limiting access to telephone dialing area |
| 06/22/1976 | US3965306 Telephone line transfer circuit |
| 06/15/1976 | US3963883 Telephone enclosure with sound prevention means |
| 06/15/1976 | US3963879 Telephone dial assembly |
| 06/15/1976 | US3963876 Amplifier circuit for increasing transmit and receive levels in a telephone hybrid network |
| 06/08/1976 | US3962664 Current protector |
| 06/08/1976 | US3962555 Telephone handset guard |
| 06/08/1976 | US3962553 Portable telephone system having a battery saver feature |
| 06/01/1976 | US3961229 Two pair station protector |
| 05/25/1976 | US3959604 Digital calling signal tone generating circuitry |
| 05/25/1976 | US3959602 Telephone substation circuit |
| 05/25/1976 | US3959600 Remotely programmable call diverter |
| 05/25/1976 | US3959591 Telephone answering apparatus |
| 05/11/1976 | US3956600 Wall telephone caddy |
| 05/11/1976 | US3956596 Circuit arrangements in telephone apparatus |
| 05/04/1976 | US3955054 Telephone housing having interchangeable dial face inserts |
| 05/04/1976 | US3955053 Integrated circuit arrangement for a telephone subscriber station |
| 04/27/1976 | US3953688 Cord reel and writing pad attachment for telephones |
| 04/27/1976 | US3953684 Static memory pulse transmitter |
| 04/27/1976 | US3953680 Remote control transcribing device |
| 04/27/1976 | US3953679 Telephone answering device utilizing Mobius loop activating switch |
| 04/20/1976 | US3952168 Rotary telephone dial structure |
| 04/20/1976 | US3952167 Electromagnetic coupler for use with a telephone set |
| 04/20/1976 | US3952166 Loudspeaking telephone circuit |
| 04/13/1976 | US3950619 Message charge control telephone answering device |
| 04/06/1976 | US3949172 Telephone extension system utilizing power line carrier signals |
| 03/30/1976 | US3947730 Telephone line surge protecting device |
| 03/30/1976 | US3947642 Telephone answering system and apparatus |
| 03/30/1976 | US3946977 Telephone unit with retractable mounting bracket |
| 03/23/1976 | US3946171 Multiple pushbutton switch assembly for telephone sets and the like |
| 03/23/1976 | US3946160 Telephone answering device with plural message recording tapes |
| 03/23/1976 | US3946158 Video-telephone system initially signifies caller to called subscriber |
| 03/16/1976 | US3943649 Telephone index devices |