Back to results
US 4,256,955 AGranted
System for keeping account of predetermined homogeneous units
AssigneeCompagnie Internationale pour l'Informatique
InventorsGeorges Giraud, Jean Mollier
Life of this patent
Estimating the term…
Loading patent…
Loading patent…
AssigneeCompagnie Internationale pour l'Informatique
InventorsGeorges Giraud, Jean Mollier
Estimating the term…
A credit card system includes a credit card containing a memory for storing coded information indicative of: an identification of the use for which the article is intended, an identification of units used to keep account of operations which are performed in connection with the credit card, and the number of units available to a holder of the credit card. The memory is structured so that the two identification data zones have bits wherein a change from one binary value to another is irreversible, to prevent tampering of the identification of the card. The card also includes circuits for controlling the memory and contacts for temporarily coupling the card to an imprinting and/or operating means that are respectively coupled to the card at the time it is purchased and when it is being used to purchase goods or services. When the card is purchased, the number of units is imprinted onto the card in the third zone, and the number of these units is decremented as the card is being used.
A system for keeping a record of predetermined homogeneous units comprising:
A system for keeping account of the credit status of a credit card holder, said credit card being adapted to be inserted into an external means for operating on binary data stored in the credit card,
In combination, a credit card having a first binary memory field having N.sub.1 bits, a second binary memory field having N.sub.2 bits, where N.sub.1 and N.sub.2 are predetermined integers greater than one, bits of said first field being subject to change in response to signals from an external device, bits of said second field not being subject to change in response to signals from an external device after having been stored in the second field, a pre-selected number of bits stored in the second field having a first binary value, the bits of the first value in the second field, once stored, being irreversible, an external device including first and second means, said first means reading bit values from and supplying bit values to the first field so that bits stored in the first field are altered in response to signals from the first means, said second means including means for reading bit values from the second field, and means for deriving an alarm signal in response to the bit values read from the second field by the second means indicating that the number of bits in the second field differs from the pre-selected number for the first value.
Dependencies are inferred from the claim text.