| 摘要 |
PROBLEM TO BE SOLVED: To search a running route which can acquire on-line information by a portable telephone as far as possible by a method wherein the running route of a vehicle is searched only inside a service area in which the on-line information can be acquired by the portable telephone. SOLUTION: When a carried portable telephone cannot receive on-line information only in the service area of a telephone company with which the telephone has entered into a contract, a route is searched only inside the service area of the telephone company. Position data on an own vehicle which is detected by a position detection part 11 is sent to a control part 13. The control part 13 reads out map data corresponding to the position of the own vehicle from a map database 12a. In addition, on the basis of the input of a telephone- company input switch 16, the service area of the telephone company with which the own portable telephone has entered into the contract is read out from a database 12b so as to be displayed on a display 2. Then, the route is searched inside the read-out service area of the telephone company in such a way that it becomes a shortest distance up to a destination point from a starting point. |
