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 and health care management cards and the like. The UET card includes storage elements, an input interface, a processor, a display,...http://www.google.es/patents/US5884271?utm_source=gb-gplus-sharePatente US5884271 - Device, system and methods of conducting paperless transactions
Device, system and methods of conducting paperless transactions
