Abstract: A USB smartphone for enabling the connection and interfacing of a standard size USB plug, typically from a USB flash drive, with a mobile computer such as a smart phone. The USB smartphone comprises a device body which include an external USB port, and internal USB mass storage device class standard software. The device body is defined as a conventional smartphone mobile computer and the USB port is defined as a downstream-port receptacle adapted to receive a Standard-A type USB plug. In operation, when a conventional USB flash drive is plugged into the device body, a directory of the USB flash drive is accessible through the display interface of the device body and files can be transferred between the memory of the device body and of the USB flash drive.