3891830 is referenced by 16 patents and cites 8 patents.

A credit verification system for use with identification cards carrying a changeable recording medium is disclosed. On presentation, cards are sensed to provide signals indicative of identification and an aggregate amount of all value transactions supported by the card during a period (month) when the card was last presented. The system develops signals indicative of an amount of value (including the contemplated transaction) supported by the card during the instant period and tests that amount against a standard that is variable by data from a record medium, which also carries identifications for unacceptable cards. Approval is indicated providing the card is acceptable and the imposed limits are not exceeded.

Credit verification system
Application Number
Publication Number
Application Date
October 12, 1973
Publication Date
June 24, 1975
Goldman Robert N
Nilsson Robbins Bissell Dalgarn & Berliner
H01h 43/08
B67d 05/10
G07f 01/06
G11b 01/06
G06k 07/08
G06K 07/08
G07F 07/08
G07F 07/02
G07F 07/00
G07F 07/12
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