| 摘要 |
PROBLEM TO BE SOLVED: To shorten a communication time, prevent the communication from being interrupted, and lower the communication cost by restricting the transfer of request map information according to a specific state when the request map information transferred from a map information providing source is received and loaded. SOLUTION: When the request map information is obtained directly from an information center 2 by using an on-vehicle portable telephone 26 without using a light beacon, the electric field intensity of the radio wave from the information center 2 is important at the reception position of the vehicle. When it is decided that the vehicle is traveling or that the electric field intensity is not larger than a specific value, it is decided whether or not a communication is being made. When the communication is being carried out, an information final flag is stored. Then a communication line is disconnected. Thus, data transfer from the information center 2 is performed only when the vehicle is stopped. Only when the electric field intensity at the stop position of the vehicle is larger than the specific value, the data transfer from the information center 2 is performed. |
