Magnetically encoded cards
US4937436A · kind A · utility
10Cited by
7References
24Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Feb 7, 1989 |
| Grant date | Jun 26, 1990 |
| Priority date | — |
| Expiry date | Feb 7, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K19/12
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A magnetically encoded card (2) has a recording track (6, 8) containing data (10, 14, 16, 18) which can be read and re-written by a card reader (30), and a further recording (12) at a much higher spatial bit denisty than the data (10, 14, 16, 18). The high denisty recording (12) is formed using a special write head capable of operating at greater bit densities than the head of the card reader used to write information to the card. The card (2) is deemed valid only if the presence of the high density recording (12) is detected by a read head (34) of the card reader.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.