Communications: electrical – Digital comparator systems
Patent
1978-05-26
1980-07-15
Yusko, Donald J.
Communications: electrical
Digital comparator systems
340142MD, H04Q 300, E05B 4900
Patent
active
042131189
ABSTRACT:
A combination changing system and method for controlling access to a locked area and updating a lock combination or memory includes encoded key cards and storing lock code combinations in a memory. Each lock may be opened by a properly encoded key card. The lock code combination is automatically changed each time a new key card is generated and used. Specifically, first and second fields of a stored code combination are stored in an active memory of the lock and first and second fields of a key code combination to be compared therewith are encoded on a key card. When the key card is inserted into a card reader connected to the lock, two fields of the stored code combination are first compared with the two fields of the key code combination, respectively. If there is a match, an appropriate signal is generated to open the lock. If there is no match, the second field of the stored code combination and first field of the key code combination are compared. If there is a match at this second stage, an appropriate signal is generated to store the two fields of the key code combination in the lock memory in place of the two fields of the stored code combination.
REFERENCES:
patent: Re29259 (1977-06-01), Sabsay
patent: 3761892 (1973-09-01), Bosnyak et al.
patent: 3800284 (1974-03-01), Zucker et al.
patent: 3821704 (1974-06-01), Sabsay
patent: 3859634 (1975-01-01), Perron et al.
patent: 3860911 (1975-01-01), Hinman et al.
patent: 3926021 (1975-12-01), Genest et al.
patent: 3944976 (1976-03-01), France
Genest Leonard J.
Madenlian Vache B.
Chromalloy Electronics Corporation
Yusko Donald J.
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