Prepaid card processing device, prepaid card processing system, and processing method for prepaid card device

A processing system for managed prepaid cards can be introduced at low cost without requiring changing POS terminals. An expansion board is used connected to an activation server that activates prepaid cards, a barcode scanner, and a POS terminal. The expansion board has a product information acquisition unit that acquires product information from the barcode scanner; a product information discrimination unit that determines if the acquired product information is for a managed prepaid card that requires activation; a product information conversion unit that converts the product information to product information data that can be interpreted by the POS terminal; a product information data output unit that outputs the product information data to the POS terminal; and an activation request unit that sends the product information with an activation request to the activation request for validation.