Patent ID: 6671814
Filing Date: 2003-12-30
Classification: G06F,Y02D

Abstract:
A USB connecting system in which a USB device is connected by a USB interface to an upper rank unit either directly or via an HUB, wherein:the upper rank unit includes a driver for sending out a control signal for turning off the power supply to the USB device; the USB device includes: power supply control means for on-off switching a 5-V power supply line for transmitting 5-V power supplied from the upper rank unit to the USB device and data lines for supplying data from the upper rank unit to the USB device side and transmitting data from the USB device side to the upper rank unit; and USB control means for transmitting a setting signal for disconnecting the 5-V power supply line and the data lines to the power supply control means when recognizing the control signal for turning off the power supply from the driver to the USB device; and power supply control means disconnects the data lines and then disconnects the 5-V power supply line in response to the setting signal from the USB control means for disconnecting the 5-V power supply line and the data lines.