Patent ID: 8478337

Claim:
A navigation device connected, via a mobile communication network, to a server by way of a telephone connected thereto via cable or radio, said navigation device comprising: a communication control unit for communicating with said server by using said telephone to measure parameter information about a command support status or communication connection environment of said telephone; and a main control unit for transmitting the parameter information measured by said communication control unit to an external storage medium or said server, and for controlling subsequent communications according to the parameter information transmitted to said external storage medium or said server, wherein: when there is a difference between said measured parameter information and the parameter information which has been transmitted to said external storage medium or said server, said communication control unit transmits parameter information corresponding to said difference to said main control unit, and said communication control unit specifies a carrier and a communication method to acquire parameter information about said communication connection environment from said external storage medium or said server via said main control unit, and, at a time which a communication connection is started and said communication control unit receives a communication connection request from said main control unit, tries to establish a connection with said telephone according to said acquired parameter information about the communication connection environment, measures, via communications with said server, parameter information about the communication connection environment including at least a connection response time and a number of connections after having succeeded in establishing said connection and making a transition to communications with said telephone, and, when there is a difference between a result of the measurement of said parameter information and said acquired parameter information about the communication connection environment, transmits parameter information corresponding to said difference to said main control unit at a time when said communication control unit fails in communicating with said telephone or the communications are disconnected.