Prodn. and transmission of encrypted functional commands - combining fixed data with variable code data modified by pseudo-random generators identically in transmission and reception

摘要

The code is transmitted by a high-frequency modulator (9) under the control of a microprocessor (2) with data memory, pseudo-random generator (3) and oscillator crystal (4). It includes fixed code data and variable data which are modified in the transmitter and receiver in accordance with the same scheme. Only a fraction of the variable code data is transmitted e.g. by UHF radio so that a third party cannot know the entire content of an encoded functional command. USE/ADVANTAGE - For car door lock security, cost is reduced and immunity from interception is improved with half the number of transmitters and receivers.