In a navigation system, display screen handling PG 2032 prepares
hierarchically a plurality of operation screens to receive the setting
from the operator, and changes the operation screen displayed on display
208 according to the content of the operation to operation button group
207 by the operator, the operation screen under the display, and said
layered structure. Further, communication control PG 2032 controls
cellular phone 30 through cellular phone IF 204 when it is necessary to
receive the information from the information service center 10 in order to
process according to the setting given by the operator through each of a
series of operation screens displayed on display 208, and establishes the
communication line between information service center 10 and this system.
And, after information is received, the communication line is cut off.
