Stand-alone access control system clock control
US4644484A · kind A · utility
16Cited by
10References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | May 22, 1984 |
| Grant date | Feb 17, 1987 |
| Priority date | — |
| Expiry date | May 22, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07C9/33
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A card reader located in proximity to the central point of the secured area having a crystal controlled time base clock. Entry is granted when the proper information is entered to the card reader through a keypad or identification card. The clock is adjusted under software control according to a selected offset signal. The card reader is operable to provide access control of a secured area according to a schedule operable relative to the card reader clock without external reference signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.