VEHICLE KEY DEVICE, VEHICLE ENGINE START CONTROL METHOD AND VEHICLE KEY SYSTEM

摘要

PROBLEM TO BE SOLVED: To accurately send and receive second signals. SOLUTION: An ignition key 10 is provided with a transmission circuit 28 to transmit wireless SW signals through radiowave when switches 16 and 18 are turned on and a transponder 30 which receives power from an antenna coil 74 provided in an ignition key cylinder 12 of a vehicle and, when it receives the power, transmits transponder code signals. When the ignition key 10 is inserted into the ignition key cylinder 12, a LED 22 installed in the ignition key cylinder 12 emits light. When the light is received by a photo diode 32 installed in the transmission circuit 28, the transmission of the wireless SW signals is prohibited.