A bar code reader having two reading windows, i. The capacitative elements are disposed on a first circle whose center is located on the pad. The manager 4 transmits a product information service message 1Gb to the customer agent 9 and a product information service message lGc to a shop agent 17. The microcoil may be used for internal magnetic resonance imaging of patient by attaching the microcoil to a catheter. Thus, when the output end of the receptacle has an abnormal current overload, the user is notified to be aware of the problem of overloading.