The occurrence of a transmission error which produces a multibit error burst in the decrypted version of a composite speech and synchronization encrypted signal using a one-bit cipher feedback or similar...
A method and apparatus is disclosed for automatically and repeatably measng the effectiveness of jamming applied against a communications link. The method is machine performed, free of the need of listener...
A repeatered, multichannel fiber optic communication network includes a plurality of full duplex fiber optic channels and one or more auxiliary channels. In order to supervise and control the operation...
A secure communications system provides a non-secure bypass circuit, which circuit is in parallel with a scrambler or other device. The scrambler is operative during a secure mode to convert data or voice...
A method for testing a digital data transmission line connected between two modems, including the steps of transmitting a test message from the first modem to the second modem, comparing the received message...
A system for producing an alarm whenever the distance between a transmitter and a receiver exceeds a predetermined distance. The transmitter includes circuitry for generating a signal having a preselected...
1. A one way communication system comprising means for transmitting coded pulse data and synchronizing pulses from a transmitter to a receiver having a source of clock pulses, monitoring means connected...
1. A system comprising a pair of stations having two parallel communication links therebetween, means for transmitting coded data signals of varying levels between the stations in opposite directions over...
The specification discloses a digital cryptographic system wherein each of the transmitting and receiving units includes a housing having a front panel. A push-button switch input array is mounted on the...
A bilateral digital signalling network couples a master station and plural remote, or satellite stations via a common communications link--as by way of an MATV coaxial cable. Any data/control signals may...
The specification discloses a system for scrambling digital signals transmitted between a synchronous data transmitting station and a receiving station. When the scrambling system is used with a facsimile...
