| 摘要 |
PROBLEM TO BE SOLVED: To provide a locking/unlocking control device which can prevent locking/unlocking operation of a key if the operation is opposed to the will of the owner. SOLUTION: According to the locking/unlocking control device, a communication circuit 21 of a communication control device 12 is comprised of a modulation circuit 31, an output switching circuit section 32, and a CMOS inverter 33. The output switching circuit 32 is formed of an NPN transistor Tr, a relay 34, and two resistances R1, R2. The resistance R1 is larger in resistance value than the resistance R2. When the relay 34 is not operated, amounts of current flowing through transmission antennas 4a, 5a are limited by the resistance R1, whereas when the relay 34 is operated, the amounts of current flowing through the transmission antennas 4a, 5a are limited by the resistance R2. The microcomputer 23 controls the relay 34 so as to assume a non-operative state when an ID code signal from a portable machine is not received. Meanwhile, the microcomputer 23 controls the relay 34 so as to assume an operative state when the ID code signal from the portable machine has been received. COPYRIGHT: (C)2003,JPO
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