System for preventing fraud in money card systems that are charged with monetary units and then used to pay for goods or services by use in a card reader, by preventing use of inductive contacts except when an access code is used

摘要

System for managing transactions between a portable device such as a card charged with monetary units and a reader device with ohmic or inductive contacts. Portable device has ohmic and inductive contacts as well as a memory that can be charged with monetary units. Data exchange takes place via the contacts and the portable device has an inhibitor device that can be used to prevent communication depending on the contact mode and or the use of an authorization code. The inhibitor can prevent communication if data transmission is via inductive contacts and no authorization code is required. This prevents fraud where the card is accessed fraudulently via the inductive contacts or to force use of ohmic connections which makes such fraud impossible.