| 摘要 |
There is disclosed herein an improved card reader for a security system utilizing a central controller and a plurality of card readers for controlling traffic through critical doors in a facility. During normal operation, the card readers read card data and send it to the central controller. The central controller makes the decision whether to grant or deny access based upon a comparison of the card data and data kept in memory regarding persons who are authorized access to certain areas. The central controller then sends a "Go" or "No Go" message, i.e., whether or not to grant access, to the reader after the access decision is made. The improved reader includes means for storing the authorized identification code data for persons who will be allowed access during times when communications between the card reader and the central controller are not working. There is also disclosed means for temporarily storing transaction information for transactions made during periods when communications with the controller are lost. During such degraded mode operation, i.e., when communications with the central controller are not working, access is granted to cardholders with the proper system code if their I.D. code data on their cards matches an I.D. code record in a table stored by the central controller in a degraded mode buffer in the reader. The I.D. codes and times of the transactions during degraded mode are, whether "Go" or "No Go", stored in a degraded mode transaction buffer in the reader. When communications are restored, the transactions saved in the transaction buffer are sent to the controller.
|
