| 摘要 |
PROBLEM TO BE SOLVED: To detect antenna connection abnormality in a separated antenna automatic tollage transaction device on-vehicle. SOLUTION: An antenna part 11 and an on-vehicle device main body part 12 connected through a coaxial cable 13 are provided, the antenna part 11 is provided with an antenna element 15 and an antenna connection detection resistor 16 connected in parallel to the antenna element 15, and the on-vehicle device main body part 12 is provided with a power supply circuit 22 for applying voltage to the antenna part 11 and an antenna connection detection circuit 23 for detecting that current is caused to flow to the antenna part 11. Because the current is caused to flow to the antenna connection detection resistor 16 with the voltage applied from the on-vehicle device main body part 12, antenna connection abnormality is detected to output an alarm from an alarming part 24 by detecting the current with the antenna connection detection circuit 23. A light emitting element can be used instead of the resistor 16. |
