Patent ID: 8688888

Claim:
A computer peripheral device adapted to a computer system having a system-end connecting interface, comprising: a device-end connecting interface detachably electrically connected to the system-end connecting interface, the device-end connecting interface comprising a power pin and a ground drain pin, wherein the power pin is electrically connected to a power source of the computer system; an impedance unit electrically connected to the power pin and the ground drain pin respectively, and the power pin generating a voltage level on the ground pin via the impedance unit when the power pin is electrically connected to the power source of the computer system; and a control unit, electrically connected to the conjunction node of the impedance unit and ground drain pin for determining a USB standard of the system-end connecting interface according to the voltage level of the ground drain pin; wherein the computer peripheral device is arranged such that when the ground drain pin floating, the voltage level of the ground drain pin is reduced to a ground voltage level.