| Patents for H04K 1 - Secret communication (16,771) |
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| 10/04/1993 | CA2065133A1 Spread spectrum communications system without a receiver synchroniser |
| 09/28/1993 | US5249227 Method and apparatus of controlling processing devices during power transition |
| 09/07/1993 | US5243650 Method and apparatus for encryption/decryption of digital multisound in television |
| 09/01/1993 | EP0558372A1 Method for hardening transmission, in particular between a control station and a transponder and apparatus for implementing said method |
| 08/31/1993 | US5241595 Communication control section for facsimile equipment having a secure communication function |
| 08/31/1993 | US5241539 Communication system with signal converter between networks |
| 08/17/1993 | US5237610 Independent external security module for a digitally upgradeable television signal decoder |
| 08/04/1993 | EP0553948A2 Digital speech encryption using encryption memory |
| 08/04/1993 | EP0553553A2 Security node in switched telecommunication network |
| 08/04/1993 | EP0515364A4 Method and apparatus for providing privacy/security in a communications system |
| 08/03/1993 | US5233654 Signal processing apparatus and methods |
| 07/27/1993 | US5231667 Scrambling/descrambling circuit |
| 07/27/1993 | US5231397 Extreme waveform coding |
| 07/07/1993 | EP0313576B1 Gateway system and method for interconnecting telephone calls with a digital voice protected radio network |
| 07/06/1993 | US5226083 Communication apparatus for speech signal |
| 07/06/1993 | US5226081 Multi-carrier communication system using ciphered carrier bit assignment information |
| 06/23/1993 | CN1073560A Wireless audio calling system working at broadcast frequency range |
| 06/22/1993 | US5222137 Dynamic encryption key selection for encrypted radio transmissions |
| 06/15/1993 | CA1319189C Cable television channel selector/descrambler for use with cable-ready video appliances |
| 06/10/1993 | WO1993011619A1 Method and apparatus for data encryption and transmission |
| 06/10/1993 | CA2080929A1 Secure telecommunications |
| 06/09/1993 | EP0489794A4 Improvements in a spread-spectrum multiplexed transmission system |
| 06/02/1993 | CN1072810A Method and apparatus for scrambling and descrambling of video signals with edge fill |
| 06/02/1993 | CN1021099C Method and apparatus for encrypting and decrypting time domain signal |
| 05/26/1993 | EP0543294A1 Method and apparatus for scrambling and descrambling of video signals with edge fill |
| 05/25/1993 | US5214694 Scramble signal transmission system for earth station of communication satellite |
| 05/04/1993 | CA1317368C Direct broadcast satellite signal transmission system |
| 04/20/1993 | US5204898 Method of protection against the unauthorized unscrambling of scrambled television broadcasts, and implementation method |
| 04/20/1993 | US5204767 Pay-channel transmission system for CATV |
| 04/14/1993 | CN1020324C In-band controller |
| 04/06/1993 | US5201066 Radio-telephone system employing a manner of changing a channel and a privacy digital code and interstoring them between a stationary apparatus and a portable apparatus by wireless and a method of changing the privacy digital code |
| 03/31/1993 | CN1020233C Method and apparatus for encrypting and decrypting time domain signals |
| 03/30/1993 | US5199074 Encryption system |
| 03/30/1993 | US5199069 Automatic encryption selector |
| 03/23/1993 | US5197098 Secure conferencing system |
| 03/23/1993 | CA1315032C Cordless telephone |
| 03/17/1993 | EP0532228A2 A cryptosystem for cellular telephony |
| 02/09/1993 | US5185797 Encrypted trunked control channel system |
| 02/09/1993 | US5185794 System and method for scrambling and/or descrambling a video signal |
| 02/09/1993 | US5185793 Method and apparatus for securing television signals using sideband interdiction |
| 01/26/1993 | US5182772 Method and apparatus for encoding, transmitting, receiving and de-coding information |
| 01/19/1993 | US5181246 Privacy communication device |
| 01/19/1993 | US5181243 System and method for communications security protection |
| 01/05/1993 | US5177785 Method and system for secure telecommunications |
| 01/05/1993 | US5177485 Method of scrambling pal, secam and ntsc composite video signals and decoder of signals scrambled by this method |
| 12/16/1992 | EP0517776A1 Hole placement and fill system based on category selection |
| 12/09/1992 | CN1066950A Independent external security module for digitally upgradeable television signal decoder |
| 12/02/1992 | EP0515364A1 Method and apparatus for providing privacy/security in a communications system |
| 12/01/1992 | US5168522 Wireless telephone with frequency inversion scrambling |
| 12/01/1992 | US5168519 System and method for securing DTMF transmission |
| 11/24/1992 | US5166976 System and method for detection of a pulse within a video signal |
| 11/08/1992 | WO1992020178A1 Spread spectrum correlator |
| 11/04/1992 | EP0511497A2 Secure communication network |
| 10/27/1992 | US5159634 Cryptosystem for cellular telephony |
| 10/20/1992 | US5157725 Method and apparatus for preventing external detection of signal information |
| 10/15/1992 | WO1992017959A1 Dynamic encryption key selection for encrypted radio transmissions |
| 10/14/1992 | CN1018697B Method and apparatus for improving video scrambling and employing split sync pulses |
| 09/30/1992 | EP0506435A2 Independent external security module for a digitally upgradeable television signal decoder |
| 09/30/1992 | EP0506405A2 Image transmission method, and apparatus therefor |
| 09/29/1992 | US5151922 Variable speaker muting based on received data |
| 09/22/1992 | US5150410 Secure digital conferencing system |
| 09/22/1992 | US5150401 Retrofittable encryption/decryption apparatus using modified frequency modulation |
| 09/16/1992 | EP0504078A1 Method and apparatus for securing television signals using sideband enhancement |
| 09/15/1992 | US5148482 RF communication unit |
| 09/15/1992 | US5148478 System and method for communications security protection |
| 09/03/1992 | WO1992015160A1 Storm alert for emergencies |
| 09/02/1992 | EP0500767A1 Audio surveillance discouragement apparatus and method |
| 09/01/1992 | US5144666 Decoder to decode an encrypted sound |
| 09/01/1992 | US5144664 Apparatus and method for upgrading terminals to maintain a secure communication network |
| 08/26/1992 | EP0398931A4 Cryptographic method and apparatus with electronically redefinable algorithm |
| 08/18/1992 | US5140635 Wireless telephone with frequency inversion scrambling |
| 08/13/1992 | DE4203436A1 Data reduced speech communication based on non-harmonic constituents - involves analogue=digital converter receiving band limited input signal with digital signal divided into twenty one band passes at specific time |
| 08/04/1992 | US5136648 Message storage security system |
| 08/04/1992 | CA1306044C Secure teleconferencing system |
| 07/21/1992 | USRE34004 Secure single sideband communication system using modulated noise subcarrier |
| 07/08/1992 | EP0403570A4 Off-premises cable television channel interdiction method and apparatus |
| 07/07/1992 | US5128523 Microcontrolled reader for smart cards |
| 07/01/1992 | EP0491840A1 Signal digitizing method and system |
| 06/17/1992 | EP0490618A1 Scrambling/descrambling circuit |
| 06/17/1992 | EP0489794A1 Improvements in a spread-spectrum multiplexed transmission system |
| 06/09/1992 | US5121430 Storm alert for emergencies |
| 06/03/1992 | EP0488289A2 Video network system |
| 06/03/1992 | EP0487701A1 Signal acquisition |
| 05/26/1992 | CA1301911C Video picture signal scrambling system |
| 05/20/1992 | EP0485887A2 Apparatus and method for upgrading terminals to maintain a secure communication network |
| 05/19/1992 | US5115466 Communication network intended for secure transmission of speech and data |
| 05/06/1992 | EP0414732A4 A method and apparatus for improving video scrambling and employing split sync pulses |
| 04/28/1992 | US5109414 Signal processing apparatus and methods |
| 04/22/1992 | EP0413752A4 In-band controller |
| 04/22/1992 | CN1016391B Cordless telephone |
| 03/31/1992 | US5101432 Signal encryption |
| 03/25/1992 | WO1992005638A1 Variable speaker muting based on received data |
| 03/24/1992 | US5099515 Secrecy device for wiretapping prevention and detection |
| 03/18/1992 | CN1015950B Duplex analog scrambler |
| 03/11/1992 | EP0474498A2 Synchronizing circuit |
| 03/11/1992 | CN1015855B Reliable group transmission mode of informations |
| 03/10/1992 | US5095540 Hole placement and fill system based on category selection |
| 03/03/1992 | US5093846 Signal acquisition using modulation by a preselected code group |
| 03/03/1992 | CA1296771C Communication system with tandem scrambling devices |
| 02/26/1992 | EP0471677A1 An information transmission system. |