| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electronic key system, capable of preventing locking and unlocking operation or engine start operation using a stolen or lost key by a third party. <P>SOLUTION: On receiving a register preparation signal transmitted from an update control device 31, a portable machine 11 records a use limit value contained in the signal in a memory 14a, and operates a counter 15. In receiving a request signal output from a locking and unlocking control device 21, the portable machine 11 transmits a first transmit signal in the condition where the count value of the counter 15 is the use limit value or smaller. On the contrary, in the condition where the count value exceeds the use limit value, the portable machine 11 transmits a second transmit signal. In receiving an update signal transmitted from the update control device 31, the portable machine 11 automatically updates the count value of the counter 15 to the initial state. <P>COPYRIGHT: (C)2003,JPO |
