Patent ID: 8001395

Claim:
A portable electronic device to be communicated with an external electronic device through a transmission line, said portable electronic device comprising: a system chip; an enabling switch triggered to issue an analog signal; a signal conversion circuit electrically connected to said enabling switch for converting said analog signal into a digital control signal; a power switching circuit electrically connected to said signal conversion circuit for selecting one of multiple power sources to be outputted as a voltage signal; a storage medium electrically connected to said power switching circuit and receiving said voltage signal; and a synchronous processing module electrically connected to said system chip, said storage medium, said signal conversion circuit, said power switching circuit and said transmission line, wherein in response to said digital control signal, said storage medium is communicated with said external electronic device through said transmission line, so that said storage medium of said portable electronic device is used as an external storage medium of said external electronic device, wherein said storage medium is communicated with said external electronic device through said transmission line when said portable electronic device is at a hibernation mode or a power-off mode.