Patent ID: 7043646

Claim:
An electronic device, comprising: an interface for data transfer including a signal line and a power supply line with a limited maximum allowable current, said interface allowing the supply of predetermined electric power to the electronic device from external equipment with power supply function only when predetermined communication is performed between the electronic device and the external equipment via the interface, and wherein said electronic device is adapted to operate with more current consumption than is provided for through a single port of said interface; said electronic device further comprising: at least two ports being included as part of the interface; control means connected to each of said at least two ports of the interface; a body portion connected to said control means; and power supply control means connected between each respective power supply line of said at least two ports of the interface and a power supply line of said body portion, wherein said control means turns on said power supply control means to thereby permit operation of the electronic device only when the supply of predetermined electric power through each of said at least two ports of the interface is confirmed as a result of communication between said control means and the external equipment.