| 摘要 |
<p>PROBLEM TO BE SOLVED: To enable always stabilized mutual communication, by detecting height of a place from ground where an apparatus mounted on a vehicle is set, and automatically changing the transmitting and receiving power in an antenna circuit for communication, according to the height. SOLUTION: A vehicle 14 is recognized from vehicle kind information decided by vehicle kind deciding equipment. The height of a place from the ground, where the apparatus (ETC wireless equipment) 13 mounted on a vehicle is set is recognized from the vehicle 14. The transmission power and reception power of the antenna 15 for communication are automatically set to the larger in the case of, e.g. an ordinary car, as compared with a large car. As a result, superior state of transmission and reception (mutual communication) is always obtained, without being affected by the kind of a car (the height of a place from the ground where the apparatus 13 is set), and the apparatus 13 enables sure fee charging.</p> |
