Circuit for controlling automatic off-line operation of an on-line card reader
First Claim
1. A security system in which coded cards are scanned at plural remote terminals to determine whether access will be permitted at plural remote locations, said system including a central processor connected to said plural remote terminals and sequentially polling said plural remote terminals to permit said remote terminals, in sequence, to transmit card data to said central processor, said central processor transmitting entry authorization or denial data to said remote terminals in response to said card data, said system comprising:
- means at one of said remote terminals for producing a start signal in response to transmission of said card data;
means at said one of said remote terminals for measuring a predetermined elapsed time period after said start signal;
means responsive to said elapsed time measuring means for producing a mode change signal whenever no entry authorization or denial data is received at said one of said remote terminals during said predetermined elapsed time period; and
means responsive to said mode change signal for permitting selective access in response to data on said coded cards at said one of said remote terminals without receipt at said terminal of said entry authorization or denial data from said central processor.
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0 Petitions
Accused Products
Abstract
A card or badge is used for controlling access to facilities or facility areas which include remote card readers which are interconnected with a central card data processor. When access is requested at a remote location, a user inserts his card or badge into the remote terminal and the remote terminal sends data identifying the person to the central processor which, in turn, sends a command to the remote terminal to grant or deny access. When a card or badge is inserted into the system and no response is received within a predetermined time period, the remote terminal, on the assumption that communication line failure has occurred between the remote terminal and the central processor, reads a set of data from the user'"'"'s card or badge to grant or deny facility access to the user on a secondary selection basis.
30 Citations
17 Claims
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1. A security system in which coded cards are scanned at plural remote terminals to determine whether access will be permitted at plural remote locations, said system including a central processor connected to said plural remote terminals and sequentially polling said plural remote terminals to permit said remote terminals, in sequence, to transmit card data to said central processor, said central processor transmitting entry authorization or denial data to said remote terminals in response to said card data, said system comprising:
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means at one of said remote terminals for producing a start signal in response to transmission of said card data; means at said one of said remote terminals for measuring a predetermined elapsed time period after said start signal; means responsive to said elapsed time measuring means for producing a mode change signal whenever no entry authorization or denial data is received at said one of said remote terminals during said predetermined elapsed time period; and means responsive to said mode change signal for permitting selective access in response to data on said coded cards at said one of said remote terminals without receipt at said terminal of said entry authorization or denial data from said central processor. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A remote terminal for use in a security system which includes other remote terminals and a central processor, said remote unit comprising:
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means for reading personnel identification data from a card inserted into said remote unit; means for transmitting said identification data to said central processor; means for receiving authorization or denial data from said central processor and for granting or denying access in response to said data; and means for measuring the elapsed time between transmission of said identification data and receipt of said authorization or denial data, and for independently controlling access if said elapsed time exceeds a predetermined value. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of controlling access to remote locations during communication failures in a security network which includes a central processor which normally controls access at plural remote terminals in response to identification data sent from said remote terminals to said central processor, comprising:
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sending identification data from one of said remote terminals to said central processor in response to actuation of said remote terminal; measuring at said remote terminal the elapsed time between said sending step and the receipt at said remote terminal of access control data from said central processor; and controlling access at said remote terminal independent of said central processor if said elapsed time exceeds a predetermined value. - View Dependent Claims (15, 16, 17)
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Specification