Abstract: This invention allows rewriting the software or data of a terminal without a user's or a maintenance personnel's directly touching the terminal. A center and a terminal are provided. The center has a unit transmitting a download start control signal to the terminal, and a unit transmitting to-be-downloaded software or data to the terminal when receiving a state switching notification signal from the terminal. The terminal has a unit determining whether a received signal is a download start control signal, a unit switching a state of the terminal to a download state if the received signal is the download start control signal, a unit transmitting the state switching notification signal to a sender of the download start control signal when the state of the terminal is changed to the download state, and a unit downloading the software or data after transmitting the download start switch notification signal.