Patent ID: 7653772

Claim:
A control system comprising: an electronic device; a hub; and one or more external devices that are capable of sequentially connecting to said electronic device, wherein said electronic device comprises: a port; a supplying section for supplying currents to said hub connected to said port and supplying currents to an external device among said one or more external devices connected via said hub; a storage section for storing the magnitude of the total current supplied from said supplying section; and a controller capable of performing operations of: calculating the magnitude of a current that can be supplied to an external device connected via said hub among said one or more external devices based on the magnitude of the total current stored in said storage section; and notifying the calculated magnitude of the current to said external device connected via said hub; and each external device among said one or more external device comprises: a judging section for judging whether said external device is operable based on the magnitude of the current notified from said electronic device; and a notifying section for notifying the judgment result made by said judging section to said electronic device, wherein said controller is further capable of performing operations of judging, in the case that a judgment result notified from a newly connected external device among said one or more external devices is that said newly connected external device is inoperable, whether another external device among said one or more external devices excluding said newly connected external device is already connected via said hub, and in the case that it is judged that said another external device is already connected, reducing current supply to said another external device among said one or more external devices excluding said newly connected external device by changing operation mode of said another external device, and supplying currents preferentially to said newly connected external device based on said newly connected external device being newly connected via said hub.