To prevent radio waves of a wireless LAN from mutually interfering with radio waves of an ETC in a mounted radio terminal, thereby avoiding causing a communication trouble.
When a controller 43 of the onboard radio terminal acquires approach information showing own vehicle approaching to an on-road machine of an ETC from a car navigator 48 (step 100: YES), it disables the terminal from communicating over the wireless LAN to avoid transmitting signals over the LAN, thereby preventing the transmission signals from arriving within a communication area of the ETC. This avoids causing a mutual interference between radio waves of the ETC and the LAN, and hence avoids causing a communication trouble in the ETC due to the mutual interference of the radio waves.
COPYRIGHT: (C)2004,JPO
Hirotaka Takeuchi
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Takahiro Miura
Fumihiro Mizuno