In the present invention, an FE device and a BE device communicate using two wireless communication routes in a separate state. Approaching of each device is determined in both devices immediately prior to a docking state by monitoring of a wireless communication state. Wireless communication between the two devices is then stopped, and both devices enter a freeze state (operation-limited state). When the docking state is then formed, wired communication is established between both devices. Then, when an unfreeze input occurs, both devices return to a normal operation state. Both devices temporarily enter the freeze state also when a state change from the docking state to the separate state occurs.
