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:
Apr. 23, 1996
Filed:
May. 10, 1994
Hartmut Schrenk, Haar, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A debit card carries an integrable electronic circuit which is electronically debited. The circuit includes a nonvolatile, electrically erasable and writable memory operated as a multi-stage counter with counter stages. The circuit is provided with a nonvolatile, electrically erasable and writable check memory which has check memory regions associated with respective counter stages of the counter memory. The card is debited in that at least one of the memory cells of a memory is read out with at least two different weighting thresholds, and the counter memory is controlled as a function of the results obtained in that reading. The reading of the carry bit and the associated check bit allow to safely prevent against manipulation and the circuit may be realized at a very low expense.