| 摘要 |
According to the present invention, a serial control signal interface and a serial data interface are provided in addition to a USB interface having a USB device controller, and a switching circuit for selectively connecting these interface to a system connector is provided on a mobile communication terminal device. Then, when an external device is connected to the system connector, it is determined whether or not the external device has an external interface having a USB host function on the basis of the interface identification voltage supplied from the external device, so that the switching circuit is changed over on the basis of the determination result to select an appropriate interface.
|
