| 5661804 |
Trainable transceiver capable of learning variable codes |
| Aug-26-1997 |
A trainable transceiver for learning and transmitting an activation signal that includes a rolling or other variable code for remotely actuating a device, such as a garage door opener. The trainable transceiver... |
| 5646996 |
Automatic resynchronization of transmitter in the event of corrupted memory |
| Jul-8-1997 |
Loss of synchronization between transmitter and receiver of a remote entry system is detected during the communication sequence between transmitter and receiver, by generating a checksum of the authentication... |
| 5610983 |
Apparatus for detecting a synchronization component in a satellite transmission system receiver |
| Mar-11-1997 |
A satellite transmission system receiver, for receiving a composite signal including a data component and a synchronization (sync) component is disclosed. The receiver includes a signal processor, responsive... |
| 5598476 |
Random clock composition-based cryptographic authentication process and locking system |
| Jan-28-1997 |
The first and second devices exchange randomly generated messages that are used in a composition-based encryption/decryption process. At least one of the randomly generated messages is, itself, encrypted... |
| 5592556 |
Digital radio with vocoding encrypting codec |
| Jan-7-1997 |
A new digital radio includes codec, vocoder and encryption/decryption processing all on a single integrated circuit chip module. Great flexibility is provided in terms of different operating modes (e.g.,... |
| 5546464 |
Method of and apparatus for selective resynchronization in a digital cellular communications system |
| Aug-13-1996 |
In a ciphered digital cellular communications system a method and apparatus are presented for selective resynchronization of the cipher upon initial channel acquisition or handoff. Where synchronization... |
| 5535278 |
Global positioning system (GPS) receiver for recovery and tracking of signals modulated with P-code |
| Jul-9-1996 |
Method and apparatus for improving the speed and accuracy of processing signals from global positioning system (GPS) receivers by ensuring access to GPS carrier signals that have been modulated with an... |
| 5528693 |
Method and apparatus for voice encryption in a communications system |
| Jun-18-1996 |
A world-wide cellular radio telecommunications system utilizing low-earth orbit satellites provides secure transmissions of voice and data even though the length of the signal path of the communications... |
| 5517187 |
Microchips and remote control devices comprising same |
| May-14-1996 |
Encoder and decoder microchips suitable for use in remote control devices, are disclosed. The encoder microchip comprises means for performing an encoding function on an identification number embedded... |
| 5506905 |
Authentication method for keyless entry system |
| Apr-9-1996 |
A system for remotely controlling a desired door locking or other function in a vehicle or other protected environment has a transmitter and receiver for communicating a message including a sequence number,... |
| 5502767 |
Method for maintaining secure information synchronization on a control channel |
| Mar-26-1996 |
Synchronization of secure information on a control channel (104) of a secure radio trunking communication system (100), is maintained by periodically transmitting control encryption parameters (CEP) (111)... |
| 5488663 |
Encoding methods for generating a digital signal containing modulated bit allocation information, and record carriers containing that signal |
| Jan-30-1996 |
Transmission system for transmitting and receiving, and subband encoding methods for generating for transmission, digital signals containing modulated bit allocation information; and record carriers containing... |
| 5420925 |
Rolling code encryption process for remote keyless entry system |
| May-30-1995 |
An encryption process for a rolling code of a remote keyless entry system. The encryption process makes use of a command code shift register, a security code shift register, and a sequence code shift register... |
| 5392355 |
Secure communication system |
| Feb-21-1995 |
A process for assuring secure communication over a radio link and apparatus to perform the process includes a scrambler-descrambler installed at a multiple line input multiple line output telephone switch.... |
| 5375171 |
Transmission system, and transmitter and receiver used in the transmission system for transmitting and receiving digital signals containing modulated bit allocation information |
| Dec-20-1994 |
Transmission system, and transmitter and receiver for use in the transmission system for transmitting and receiving digital signals containing modulated bit allocation information. The transmitter encodes... |
| 5369706 |
Resynchronizing transmitters to receivers for secure vehicle entry using cryptography or rolling code |
| Nov-29-1994 |
Secret Information is stored in the transmitter and receiver of the keyless entry system. The information includes a resynchronization authorization code. When resynchronization is requested by the user... |
| 5363448 |
Pseudorandom number generation and cryptographic authentication |
| Nov-8-1994 |
An automobile door lock receiver module (30) and a plurality of keychain fob transmitter units (16) contain identification numbers, secret initial values, and secret feedback masks so as to authenticate... |
| 5361302 |
Method for encryption sync compression in an encrypted radio telephone interconnect system |
| Nov-1-1994 |
A method for transparently coupling an encrypted two-way RF communication unit (100) with an encrypted landline communication unit (104). An RF message comprised of a plurality of data frames (401,402,... |
| 5341427 |
Algorithm independent cryptographic key management apparatus |
| Aug-23-1994 |
An apparatus for secure communications contains a controller for automatically selecting one of several data ciphering devices utilizing one of a plurality of ciphering algorithms common to transmitting... |
| 5293423 |
Synchronizing method in a mobile radio system |
| Mar-8-1994 |
A synchronizing method in a mobile radio system which operates with Time Division Multiple Access (TDMA) but which lacks global time reference for all base stations and mobiles in the system. The inventive... |
| 5278907 |
Analog scrambling with continuous synchronization |
| Jan-11-1994 |
A device and method for scrambling and de-scrambling audio and voice communications including radio, cellular telephone, and conventional telephone communication. The audio communication can be scrambled... |
| 5243653 |
Method and apparatus for maintaining continuous synchronous encryption and decryption in a wireless communication system throughout a hand-off |
| Sep-7-1993 |
In a wireless communication system comprising a plurality of fixed communication units (FCUs) (102) and portable communication units (PCUs) (120), each comprising an encryption synchronization counter... |
| 5191610 |
Remote operating system having secure communication of encoded messages and automatic re-synchronization |
| Mar-2-1993 |
A remote operating system for remote-controlled operation of a device provides secure communication of encoded messages between a transmitter (100) and receiver (150) of the system, and provides automatic... |
| 5185797 |
Encrypted trunked control channel system |
| Feb-9-1993 |
A trunked communication system (400) transmits and receives encrypted signals over the system control channel (402). The trunked system (b 400) includes a plurality of radios (300) which can communicate... |
| 5164986 |
Formation of rekey messages in a communication system |
| Nov-17-1992 |
Formation and sending of rekeying messages (305, 415, 515, and 605) in an encrypted communication system with over-the-channel rekeying of communication units is performed by a KMC, key management controller... |
| 5148482 |
Layered session data unit frame |
| Sep-15-1992 |
A layered session data unit frame (300) is provided wherein a first frame (200), designated a session data unit("SDU"), containing user information (209), a link control field (205) and an encryption field... |
| 5081679 |
Resynchronization of encryption systems upon handoff |
| Jan-14-1992 |
A system for the synchronization of encryption and decryption in a duplex cellular radio system in which an encrypted call may be switched from one cell to another. At the instant of handoff, a rapid first... |
| 5073932 |
Secured data transmission and error recovery mechanism in cordless telephones |
| Dec-17-1991 |
A novel method is disclosed that facilitates secured transmission of data between the transmitting and receiving ends of a cordless telephone by encapsulating the desired command in a message code. This... |
| 5060266 |
Continuous cipher synchronization for cellular communication system |
| Oct-22-1991 |
A system for the synchronization of encryption devices in a digital cellular communications system. Each of the encryption devices includes a multi-bit counter and generates a pseudo-random keystream which... |
| 4995083 |
Method of establishing a radio link in one of a plurality of channels between two radio units |
| Feb-19-1991 |
The method comprises transmitting an initiating signal in the form of a bit pattern as a continuous burst from one radio unit to the other. The pattern incorporates a preamble pattern and a security code... |
| 4969191 |
Fully digital phase-locked loop |
| Nov-6-1990 |
A fully digital phase-locked loop comprises a sampler (1), an analog-to-digital converter (2), two quadrature demodulators (3 and 4) and their associated filters (5 and 6), and a decision logic (7) effecting... |
| 4937867 |
Variable time inversion algorithm controlled system for multi-level speech security |
| Jun-26-1990 |
A method for scrambling speech such as in a mobile land based communication system is disclosed. Essentially, variable length time samples of digitized speech are stored and time inversion scrambled. The... |
| 4924516 |
Method and system for a synchronized pseudo-random privacy modem |
| May-8-1990 |
A method and system for a synchronized pseudorandom privacy modem makes use of a pseudorandom signal generator to index into a table of N signal spaces thereby altering gain and phase modifiers so or to... |
| 4914696 |
Communications system with tandem scrambling devices |
| Apr-3-1990 |
An intermediate scrambling device for a radiotelephone system is disclosed by which it is possible to establish and maintain scrambled communications between an originating scrambler terminal and the most... |
| 4893339 |
Secure communication system |
| Jan-9-1990 |
Disclosed is a synchronous secure communication system wherein an information signal is encrypted in an encryption means. The encrypted signal is compressed to allow the insertion of a synchronization... |
| 4837821 |
Signal transmission system having encoder/decoder without frame synchronization signal |
| Jun-6-1989 |
A privacy code-type signal transmission system includes a transmitter having a signal sampler for producing analog samples of an analog audio signal, an analog to digital converter, a scrambler, a multi-level... |
| 4817146 |
Cryptographic digital signal transceiver method and apparatus |
| Mar-28-1989 |
Hybrid subband coding and decoding (using different encloding/decoding algorithms in at least one subband channel) and subband time delay compensation at a point of maximum digital bandwidth compression... |
| 4803726 |
Bit synchronization method for a digital radio telephone system |
| Feb-7-1989 |
A method and means for maintaining continuous bit synchronization of data transmitted from a remote unit through a base unit to a landline unit is disclosed. An input data stream at a first bit rate, such... |
| 4790012 |
Encryption-decryption system |
| Dec-6-1988 |
In a data encrypting/decrypting system both the encoding and decoding stations are receptive of a common source of time varying digital signals. The digital signals in the encoding station are applied... |
| 4790009 |
Scrambler system |
| Dec-6-1988 |
A scrambler system comprises in a transmitter part thereof as oscillator circuit for generating a local oscillation signal, a frequency dividing circuit for obtaining a frequency divided signal by frequency-dividing... |
| 4757536 |
Method and apparatus for transceiving cryptographically encoded digital data |
| Jul-12-1988 |
Method and apparatus are disclosed for transceiving digital control and cryptographically encoded data signals in a unique format. The format includes frame synchronization, cryptographic synchronization... |
| 4688257 |
Secure wireless communication system utilizing locally synchronized noise signals |
| Aug-18-1987 |
Apparatus and method are disclosed for synchronziing the operation of the frequency sensitive devices of two or more transceiver units in a secure, wireless communication system. A fixed frequency pilot... |
| 4550222 |
Process for interception-protected frequency band compressed transmission of speech signals |
| Oct-29-1985 |
In order to achieve a good masking, together with minimum bandwidth requirement of sample values of spectral channels which are to be transmitted in the timing of consecutive analysis intervals in a time... |
| 4434323 |
Scrambler key code synchronizer |
| Feb-28-1984 |
A method for synchronizing the scrambling sequences of communicating scrambler units of a privacy communications system in a reliable and secure manner. The method is particularly adapted for use in noisy... |
| 4305152 |
Security communication system |
| Dec-8-1981 |
A security communication system comprises a transmission apparatus including a scrambling circuit for scrambling an information signal according to a specific code and a reception apparatus including a... |
| 4232187 |
Teletype character modification unit |
| Nov-4-1980 |
3. A teletype modification unit comprising: a signal shaper having input ns for receiving mark-space teletype pulses; a synchronization circuit coupled to said signal shaper; a plurality of delay means... |
| 4214126 |
Cadence suppression system |
| Jul-22-1980 |
1. A secret telecommunication system including a source of communication signals, a signal cadence suppression circuit including means responsive to the envelope of said communication signals for generating... |
| 4163872 |
Secret pulse signaling system |
| Aug-7-1979 |
1. A radio pulse signalling system comprising, oscillator means generating first timing wave which is comprised of a controlled number of cycles, means transmitting a pulse signal at the start of said... |
