An IC card which has a timer circuit that shuts off the IC card within a predetermined time interval is used with a terminal which resets the timer circuit in the IC card in response to any terminal operations. This prevents the IC card from shutting itself off during the terminal operations....http://www.google.fr/patents/US5146068?utm_source=gb-gplus-shareBrevet US5146068 - System for authenticating an authorized user of an IC card
System for authenticating an authorized user of an IC card
