| 摘要 |
PROBLEM TO BE SOLVED: To self-diagnose the abnormality of an antenna in a toll collecting/ receiving system independently of communication with an on-vehicle equipment. SOLUTION: A transmission signal 210 from a roadside equipment 100 is converted by a transmission circuit 201 and the converted signal is transmitted from an antenna part 203 as a transmitting radio wave 211. At the time of receiving the radio wave 211, an on-vehicle equipment 400 entering into a communication area puts its own ID on a time slot specified by the transmission signal and returns a receiving radio wave 221. A receiving circuit 202 outputs receiving data 240 extracted from a receiving signal 220 to the roadside equipment 100. A transmission signal specifying the reception of the ID is outputted from the equipment 100 and information necessary for settlement processing is answered from the on-vehicle equipment having the ID. When the equipment 400 does not exist in the communication area, data 230 extracted from a transmitting time slot of a radio wave 221' directly receiving the radio wave 211 are outputted to a monitoring circuit 204 and collated with the transmission signal 20. At the time of unequal comparison, a signal 250 showing the abnormality of the antenna is outputted to the equipment 100. |
