[li] Patent Number: 4,710,613 [45] Date of Patent: Dec. 1, 1987
[54] IDENTIFICATION SYSTEM
[75] Inventor: Yoshimi Shigenaga, Tokyo, Japan
[73] Assignee: Casio Computer Co., Ltd., Tokyo, Japan
[21] Appl. No.: 805,187
[22] Filed: Dec. 4,1985
[30] Foreign Application Priority Data
Dec. 13, 1984 [JP] Japan 59-263331
[51] Int. CI." G06K 5/00
[52] U.S. CI 235/380; 235/379;
235/493; 340/825.34; 380/25
[58] Field of Search 235/379, 380, 382, 493;
380/24, 25; 340/825.34
[56] References Cited
U.S. PATENT DOCUMENTS
4,123,747 10/1978 Lancto et al 380/25
4,423,287 12/1983 Zeidler 235/382 X
4,529,870 7/1985 Chaum 235/379 X
An identification system wherein validity between a first unit and a second unit is identified when the first unit is electrically communicated with the second unit. The first unit includes a generator for generating identification code information, a calculator for calculating, based upon the identification code information, an estimation time required for processing the identification code information in the second unit, a time counter for measuring an actual time required for completely processing the identification code information in the second unit, and an unit for identifying validity between said first and second units by comparing the actual processing time to the estimation processing time. The second unit includes at least a processor for processing the identification code information sent from the first unit.
14 Claims, 7 Drawing Figures
