发明名称 |
Stand-alone access control system clock control |
摘要 |
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.
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申请公布号 |
US4644484(A) |
申请公布日期 |
1987.02.17 |
申请号 |
US19840612687 |
申请日期 |
1984.05.22 |
申请人 |
AMERICAN DISTRICT TELEGRAPH COMPANY |
发明人 |
FLYNN, KEVIN;SCHULTZ, ERIC V. |
分类号 |
G07C9/00;(IPC1-7):G08B1/00 |
主分类号 |
G07C9/00 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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