| 5602916 |
Method and apparatus for preventing unauthorized monitoring of wireless data transmissions |
| Feb-11-1997 |
Preventing unauthorized monitoring of wireless data transmissions is accomplished by routing requests for data, from communication units (114) operating on wireless communication systems (101), to a security... |
| 5594797 |
Variable security level encryption |
| Jan-14-1997 |
A method and apparatus for digital cellular telephone encryption includes a switch when a choice between compatibility security and a higher security is required. Plaintext is converted into ciphertext... |
| 5594796 |
Method and apparatus for detecting unauthorized distribution of data |
| Jan-14-1997 |
Unauthorized distribution of data within a wireless communication system (101-102) can be detected by coupling a security gateway (103) between the wireless communication system (101-102) and a public... |
| 5592555 |
Wireless communications privacy method and system |
| Jan-7-1997 |
A method and system for privately communicating signals over a wireless communications network include the steps of and circuitry and instructions for processing communication signals in a first signal... |
| 5574788 |
Trunked radio repeater system |
| Nov-12-1996 |
A digitally trunked radio repeater system provides substantial improvements in timeliness of channel acquisition and channel drop, and in reliability of critical control signalling. The system uses a much... |
| 5568553 |
Cordless phone system capable of scrambling communication signals |
| Oct-22-1996 |
A cordless phone system includes a first cordless phone and a second cordless phone which are coupled to each other by a network, the first cordless phone being formed of a first personal station and a... |
| 5539824 |
Method and system for key distribution and authentication in a data communication network |
| Jul-23-1996 |
This invention deals with a safe key distribution and authentication in a data communication network (e.g. wireless LAN type of network). The network includes a network manager to which are connected,... |
| 5526435 |
Communications apparatus for scrambling data and synchronizing a plurality of terminals |
| Jun-11-1996 |
The invention prevents unauthorized use of data in communications. When terminals with different data transmission rates are simultaneously connected to a host computer, the host computer sets a single... |
| 5508692 |
Central locking installation for a motor vehicle |
| Apr-16-1996 |
The invention relates to a central locking installation for a motor vehicle, having a transmitter (2), operating as a key, and a receiver (4), operating as a lock. When the transmitter (2) is actuated... |
| 5508687 |
Remote control, in particular for a locking device |
| Apr-16-1996 |
A remote control for a locking device, especially in a motor vehicle, including a control or operating unit for the transmitting of key words to the evaluating circuit of a reading unit fora comparison... |
| 5500888 |
Cordless telephone security code initiation and prevention system |
| Mar-19-1996 |
A method and structure for increasing the security of a cordless telephone system by automatically altering the security code information stored in the cordless telephone handset and base unit. Thus, without... |
| 5499295 |
Method and apparatus for feature authorization and software copy protection in RF communications devices |
| Mar-12-1996 |
A hardware-software security arrangement enables manufacturers of digital RF communications equipment to provide differently configured products having substantially identical hardware and operational... |
| 5481610 |
Digital radio transceiver with encrypted key storage |
| Jan-2-1996 |
A digital radio has standardized "key" storage for several different cryptosystems (DES, VGE, VGS, etc.). Cryptographic keys are stored in a table in non-volatile memory such as EEPROM. The "keys" are... |
| 5481561 |
Fully meshed CDMA network for personal communications terminals |
| Jan-2-1996 |
A network of personal communications terminals communicating in a CDMA mode includes a reference station for transmitting a pilot tone that is pre-corrected at the reference station and is used at the... |
| 5457748 |
Method and apparatus for improved security within encrypted communication devices |
| Oct-10-1995 |
Within a communication device which utilizes digital encryption, volatile and non-volatile memory devices are used for the storage of encryption keys in unencrypted and encrypted form, respectively. A... |
| 5454040 |
Digital control of analog systems |
| Sep-26-1995 |
An audio mixing console incorporates a number of audio modules connected in series, with the first module being serially connected to a digital controller. The digital controller provides digital signals... |
| 5422952 |
Dynamic radio communications system |
| Jun-6-1995 |
A communication system includes a plurality of subscribers each of said subscribers having a transceiver including a transmitter and a receiver. In the system there are means coupled to each of said transceivers... |
| 5410602 |
Method for key management of point-to-point communications |
| Apr-25-1995 |
A method of secure key distribution in a communication system having a plurality of subscriber units and an infrastructure communication center is provided. A first subscriber unit sends a request to the... |
| 5406628 |
Public key authentication and key agreement for low-cost terminals |
| Apr-11-1995 |
A method for achieving mutual authentication and session key agreement between a first party 12 which has minimal computational resources and a second party 18 which has substantial computational resources... |
| 5406626 |
Radio receiver for information dissemenation using subcarrier |
| Apr-11-1995 |
A radio receiver receives FM subcarrier transmissions, and stores the transmitted textual information in a random access memory. The information is typically news, weather, sports, entertainment or other... |
| 5392354 |
Cordless phone system capable of scrambling communication signals |
| Feb-21-1995 |
A cordless phone system includes a first cordless phone and a second cordless phone which are coupled to each other by a network, the first cordless phone being formed of a first personal station and a... |
| 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.... |
| 5392353 |
Interactive satellite broadcast network |
| Feb-21-1995 |
Encrypted communications ensure privacy of communications point-to-point in a network of interactive video stations interconnected by a broadcast network. The encryption as a function of personal identity... |
| 5392352 |
Scramble detecting circuit in a satellite broadcasting receiver and scramble detecting method |
| Feb-21-1995 |
In a satellite broadcasting receiver for receiving and decoding pulse code modulation (PCM) audio frame data having a plurality of channels, the logical state of charged flags (FD) included in the data... |
| 5384845 |
Command modulation system having command generator unit for commanding a plurality of different types of controlled units |
| Jan-24-1995 |
A command modulation system receives commands from a plurality of input sources, some local and some remote, and routes the commands to a plurality of commanded devices, which may be satellites. By use... |
| 5365590 |
System for providing access to digitally encoded communications in a distributed switching network |
| Nov-15-1994 |
A distributed switching network (switch) routes audio and control signals throughout the switch from various audio sources to one or more audio destinations. Audio sources such as mobile/portable radio... |
| 5365585 |
Method and apparatus for encryption having a feedback register with selectable taps |
| Nov-15-1994 |
A method and apparatus for generating a pseudo-random bit sequence is provided. A first input bit is determined as a function of bits stored in a shift register in accordance with a first feedback algorithm.... |
| 5333198 |
Digital interface circuit |
| Jul-26-1994 |
A digital interface for allowing a first device which receives and sends information serially to communicate with a second device which receives and sends information in parallel. The first device may... |
| 5319711 |
Wireless device for verifying identification |
| Jun-7-1994 |
A wireless communication device using a verification protocol for verifying the identification of the wireless device by a wireless network control station in the presence of eavesdroppers is disclosed.... |
| 5307370 |
Secure cordless radio-telephone |
| Apr-26-1994 |
A frequency-hopping cordless telephone system is described which adds digitized audio to a pseudorandom frequency hopping pattern for voice encryption. The randomly selected start point of a very long... |
| 5297203 |
Digital cordless telephone apparatus |
| Mar-22-1994 |
A digital cordless telephone apparatus comprising a microprocessor based battery powered portable handset unit and a microprocessor based stationary base unit which each transmit and receive digital voice... |
| 5285496 |
Methods and apparatus for providing a secure paging system |
| Feb-8-1994 |
A paging system which sends and receives encrypted messages. The message may be encrypted either by the sender of the message or by the paging system. Multiple keys may be used for encrypting and decrypting.... |
| 5249227 |
Method and apparatus of controlling processing devices during power transition |
| Sep-28-1993 |
A voltage sensing circuit is used to determine when the current supply to a processing unit is under transition. During power up transitions, the voltage sensing circuit allows the processing unit to reset... |
| 5249199 |
Method and apparatus for reducing spurious noise levels in an audio system |
| Sep-28-1993 |
An audio system (600) typically includes an audio signal processor (610), a controller (607) for controlling data signals, and a peripheral data source (613). The audio signal processor (610) exchanges... |
| 5222247 |
Method for maximizing channel selection in a communication system |
| Jun-22-1993 |
A communication system (100) has at least one base site (204) which includes a plurality of transceivers (110A-C) operating on a plurality of communication channels for communicating to at least one of... |
| 5199074 |
Encryption system |
| Mar-30-1993 |
A communication system transmits and receives encrypted digital signal samples. The system includes a generator for generating digital signal samples to be encrypted and an encryption memory for storing... |
| 5199069 |
Automatic encryption selector |
| Mar-30-1993 |
A radio (100) capable of automatically selecting an encryption algorithm from among a plurality of algorithms (122 and 124) is disclosed. The method for automatically selecting the proper encryption hybrid... |
| 5164985 |
Passive universal communicator system |
| Nov-17-1992 |
A communication system includes a base station, called a "Controller" and one or more remote or satellite stations, each called a "Communicator". The controller arbitrates, controls and communicates with... |
| 5161194 |
Satellite communications system operating in asynchronous mode for central-to-terminal station transmission |
| Nov-3-1992 |
In a satellite communications system, a unique word is transmitted from a central station at frame intervals to the satellite and broadcast to terminal stations. Blocks of data from the central station... |
| 5161189 |
Encryption and decryption of chained messages |
| Nov-3-1992 |
A single sync field (501) and multiple messages or message segments (503, 507, 511, and 515) are chained (407) together and encrypted (407) as a whole. When this encrypted chained message is received,... |
| 5127051 |
Adaptive modem for varying communication channel |
| Jun-30-1992 |
An improved modem system for HF data transmission over a varying communication channel transmits data in packets formatted into successive frames, each having two identical training sequences following... |
| 5113443 |
Method for scrambling satellite communications |
| May-12-1992 |
A secure communications system multiplexes segments of the information signal for keyed encoding and modulation onto a plurality of different carrier frequencies and/or polarizations, and transmits the... |
| 5101430 |
Method and device for generating and for validating a digital message and application of such a device |
| Mar-31-1992 |
In this method, a number N is assigned to transmitted and receiving stations comprising synchronous clocks (2), the coded message being obtained by calculating a time Tie from the time elapsed since the... |
| 5097505 |
Method and apparatus for secure identification and verification |
| Mar-17-1992 |
A method and apparatus for performing personal identification and/or verification at perdetermined stations or checkpoints is provided. Each person to be identified has a unit such as a card, badge or... |
| 5077791 |
Method and apparatus for preventing unauthorized transmissions |
| Dec-31-1991 |
Each subscriber unit (108) operating on a communication system (100) selects either encrypted or unencrypted transmission mode as a current transmission mode. Before participating in a communication, each... |
| 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... |
| 5058161 |
Method and apparatus for secure identification and verification |
| Oct-15-1991 |
A method and apparatus for performing identification and/or verification at predetermined checkpoints is provided. A selected radiation, such as an RF signal or an ultrasonic signal at a predetermined... |
| 5054068 |
Trunked radio communication system having encrypted system control information |
| Oct-1-1991 |
A trunked communication system having a control resource that encrypts system control messages. In one embodiment, the encryption includes controlling a bit interleaving process (208, 311) as a function... |
| 5003598 |
Secure communication system |
| Mar-26-1991 |
A secure communication system comprising signal manipulation and inverse signal manipulation means at the sending and receiving locations respectively, the signal manipulation processes being controlled... |
| 5001751 |
Mode 4 reply decoder |
| Mar-19-1991 |
A reply decoder (30) for declaring mode 4 replies when used with a KIR cryptograph computer (25) is described including timing logic (114), memory (112) for storing mode 4 replies and logic circuitry for... |
