| 摘要 |
PROBLEM TO BE SOLVED: To provide a door lock system whose shape is proper to hold confidential communication between a door side device and a portable transmitter- receiver by allowing a vehicle side device to detect an opening action of a door and transmit a call signal to the other party. SOLUTION: A CPU 11 in a vehicle side device 10, when it receives a response signal from a portable transmitter-receiver 20, compares an identification number contained in the response signal, with a registered identification number. When they are identical to each other and a comparison is made whether or not an included functional value is identical to a prepared functional value. When they are identical to each other as a result, a required travel time is calculated and the distance up to the transmitter-receiver 20 fails to exceed a specified threshold value, a door lock release operation will be executed. As described above, the call signal is arranged to include an ID code of a vehicle side device and functional values of random numbers. In the case when the call signal is arranged to include only random numbers while the response signal is arranged to include only the functional values of random numbers, the functional values common to both devices will perform a similar function to a password code. |
