The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 03, 1997
Filed:
Aug. 25, 1995
Albertus Feiken, Amstelveen, NL;
Koninklijke PTT Nederland N.V., Groningen, NL;
Abstract
Improved integrity of a payment system for paying for services or goods, for example, telephone facilities, through use of electronic payment cards. In any session to increase a card balance, a 'flag' is placed ('1') on the payment card which indicates that the session must not be interrupted. After completion, the flag is removed again ('0'). A session to pay for the product or the service or to increase the balance can only be established if the flag is absent ('0') indicating that the last session to increase the balance was correctly completed. If, on the other hand, the flag is still '1' at the start of a session, a correction routine is first performed in which the previous session to increase the balance is then correctly concluded to prevent the flag being removed by fraud, the flag can only be removed by a central system (PSTN/ABS) through issurance of an authorized instruction.