To provide a means capable of reliably determining that a crew member carrying a mobile phone approaches to a particular door among a plurality of doors of a vehicle without causing any increase in electric power consumption.
Identifying information for each of transmitting antennas 11, 12 and 13 is included in a transmission request signal transmitted from a plurality of the transmitting antennas 11, 12 and 13 installed correspondingly to a plurality of doors of the vehicle. Additionally, identifying information corresponding to the identifying information included in the received transmission request signal is included in a response signal replied to the transmission request signal by a mobile phone 2 receiving the transmission request signal. Any particular door to which a crew member carrying the mobile phone 2 approaches among the plurality of doors of the vehicle is identified based on an antenna ID contained in the response signal received from the mobile phone 2 by a control circuit 25 in a control unit 10 of onboard equipment 1; and a lamp corresponding to the door identified as being approached by the crew member of the vehicle is turned on.
Iwa Saki Kokuni
Kawamata Sumio
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu