A universal electronic transaction card ("UET card") is capable of serving as a number of different credit cards, bank cards, identification cards, employee cards, medical cards and the like. The UET card includes information storage elements, an input interface, a processor, a display, and a communications...http://www.google.de/patents/US5590038?utm_source=gb-gplus-sharePatent US5590038 - Universal electronic transaction card including receipt storage and system and methods of conducting electronic transactions
