Patent ID: 7474200

Claim:
A vehicle device control system comprising a vehicle-side unit included in a vehicle and a portable device for performing mutual communications, in which the portable device returns a response signal in response to a request signal transmitted from the vehicle-side unit in at least a communication area which includes a luggage compartment of the vehicle so as to control an operation of a vehicle device on the basis of a result of the communications, wherein the vehicle-side unit includes: a transmitter which selectively transmits, as the request signal, a first request signal and a second request signal; a receiver which receives the response signal; determination means for determining an open/closed state of a luggage compartment door; and instruction means for instructing the transmitter to transmit the first request signal when the determination means determines that the luggage compartment door is in the closed state, and for instructing the transmitter to transmit the second request signal when the determination means determines that the luggage compartment door is in the open state; and wherein the portable device includes: a receiver which is capable of receiving the first and second request signals; a transmitter which transmits the response signal; and output adjustment means for adjusting a transmission output of the response signal which is to be transmitted from the transmitter so as to become lower than when the first request signal has been received by the receiver, when the second request signal has been received.