| 摘要 |
PURPOSE: To prevent a user not knowing a cryptology from driving a television receiver by setting an optional cryptograph to the television receiver and driving the television receiver normally only when a key signal similar to the cryptograph is received and the cryptograph is released. CONSTITUTION: When a power key of a key board section 1 is depressed, a microcomputer 4 conducts normal operation similarly to a conventional television receiver when no cryptograph N1 is set. When any cryptograph N1 is set, a voice cancellation signal is outputted so as to prevent a voice signal from being outputted and a video cancellation signal and a switching signal are outputted and a video signal outputted from a detection section 62 does not pass through a switching section 63 and a screen character display signal outputted from the microcomputer 4 is displayed on a cathode ray tube 67 through the switching section 63. Thus, the user recognizes the setting of the cryptograph and the key board 1 is operated to enter a cryptograph key signal to the microcomputer 4, then an output of the video and audio cancellation signal is interrupted and the output of the switching signal is interrupted and then the normal operation is restored. |
