| 摘要 |
PROBLEM TO BE SOLVED: To considerably improve the convenience in using a system by locking or unlocking the door of a motor vehicle only by coming close to or going far from the motor vehicle while a person is carrying an IC card but without operating the IC card thereby reducing the power consumption in the IC card. SOLUTION: When an IC card 4 is held in the hand and raised, it is detected by a permanent magnet, a detection coil and a portable detection signal creating circuit, an FM signal is transmitted from the side of the IC card 4, the FM signal is received by a vehicle side device 3, a door 5 of the motor vehicle 2 is locked or unlocked. And by coming closer to the motor vehicle 2, communication by FM signal can be forcefully stopped when the communication by the electromagnetic induction method becomes possible. |
