A radio wave from a base station, which is received in a radio unit (TRX) 2 of a terminal, contains an identification signal of the base station. A base station identification signal detecting unit 3 detects the base station, from which the radio wave is received, and the CPU 5 makes a judgment. The input level of the received radio wave and the time can be known from an electric field intensity measuring unit 4 and a clock 7, respectively. The terminal has a table, in which times and places meeting communication conditions are registered. A communication time is predicted from the data quantity to be transmitted, and the time and place of the connection trial start are selected. A link is set up periodically at a time and a place meeting conditions, which are determined with reference to the table, thus permitting automatic exchange of data, if any, to the terminal or link destination.