A customer service system for use in an IC card system comprises a customer's IC card, a display, a display controller, and a customer's IC card read-write unit. The IC card includes an IC having a first memory for storing an ID number, a second memory for storing secret data, an interface for controlling...http://www.google.es/patents/US4752677?utm_source=gb-gplus-sharePatente US4752677 - Customer service system for use in IC card system
