These procedures effectively allow such devices to function as an electronic wallet, a wireless PIN pad, and a contactless Smart Card....http://www.google.fr/patents/US5991749?utm_source=gb-gplus-shareBrevet US5991749 - Wireless telephony for collecting tolls, conducting financial transactions, and authorizing other activities Recherche avanc???e dans les brevets Num???ro de publicationUS5991749 A