Patent ID: 7719607

Claim:
An electronic device system having a detachable and chargeable secondary battery, the device system comprising: a secondary battery determination part which determines whether said secondary battery is a genuine battery, which is designed appropriate for said electronic device, in accordance with unique identification information output from a controller of said second battery; a message output part which outputs an error message when said secondary battery determination part determines that said secondary battery is not the genuine battery; a normal control part which allows said electronic device to operate normally when said secondary battery determination part determines that said secondary battery is the genuine battery; and a minimum power mode shifting part which shifts the operation of said electronic device to a minimum power mode when said secondary battery determination part determines that said secondary battery is not the genuine battery, wherein: said minimum power mode shifting part accepts only switch operation processing during the minimum power mode; and said message output part outputs the error message when the switch operation processing is accepted during the minimum power mode.