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US5367149A
Expired / Lapsed
US
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IC card and method of checking personal identification number of the same
Assignee: Renesas Electronics Corp
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Filing: 1993-08-19
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Granted: 1994-11-22
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Expires: 2013-08-19
Abstract
Abstract An IC card according to the present invention includes data processing means for processing data; a memory for storing a personal identification number; a power-supply terminal to which a power-supply voltage is applied by an external unit; an input/output terminal for inputting data from and outputting data to the external unit; a voltage detecting circuit for detecting the power-supply voltage applied to the power-supply terminal from the external unit; and a check-processing circuit for verifying a personal identification number input from the external unit by comparison with a personal identification number stored in the memory in response to a command for verifying applied to the input/output terminal when the power-supply voltage detected in the voltage detecting circuit is at least equal to a threshold voltage and constantly responding that an identification error has occurred when the power-supply voltage detected in the voltage detecting circuit is lower than the threshold voltage.
Inventors
- 👤 Kenichi Takahira
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:53
CPC Classifications
G; G07; G07F; G07F7/00; G07F7/08; G07F7/10; G07F7/1008; G07F7/1025
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
159 words
An IC card comprising: data processing means for processing data; a memory in which a personal identification number is stored; a power-supply terminal to which a power-supply voltage is applied from an external unit; an input/output terminal for inputting data from and outputting data to the external unit; a voltage detecting circuit for detecting the power-supply voltage applied to said power-supply terminal from the external unit; and check-processing means for verifying a personal identification number input from the external unit by comparison with the personal identification number stored in said memory in response to a command for verifying the identification number from the external unit applied to said input/output terminal when the power-supply voltage detected by said voltage detecting circuit is at least a predetermined threshold voltage, said check-processing means constantly responding to the command that an error occurred in the comparison when the power-supply voltage detected in said voltage detecting circuit is lower than the predetermined threshold voltage.
Claim 2
Dependent Claim
159 words
An IC card comprising: data processing means for processing data; a memory in which a personal identification number is stored; a power-supply terminal to which a power-supply voltage is applied from an external unit; an input/output terminal for inputting data from and outputting data to the external unit; a voltage detecting circuit for detecting the power-supply voltage applied to said power-supply terminal from the external unit; and check-processing means for verifying a personal identification number input from the external unit by comparison with the personal identification number stored in said memory in response to a command for verifying the identification number from the external unit applied to said input/output terminal when the power-supply voltage detected by said voltage detecting circuit is at least a predetermined threshold voltage, said check-processing means constantly responding to the command that an error occurred in the comparison when the power-supply voltage detected in said voltage detecting circuit is lower than the predetermined threshold voltage.
Claim 3
Dependent Claim
13 words
The IC card according to claim 1 wherein said memory is an EEPROM.
Claim 4
Dependent Claim
25 words
The IC card according to claim 2 comprising a RAM for storing data temporarily and a ROM for storing a program for operating said CPU.
Claim 5
Dependent Claim
36 words
The IC card according to claim 1 wherein said check-processing means repeatedly responds to the command that an error occurred when the power-supply voltage detected in said voltage detecting circuit is lower than the threshold voltage.
Claim 6
Independent Claim
129 words
A method of checking a personal identification number in an IC card, said method comprising: writing predetermined dummy data in a memory in an IC card in response to a command to check a personal identification number input to the IC card from an external unit; reading out from the memory the dummy data written into the memory; determining whether accurate writing occurred by comparing the read-out dummy data with the written-in dummy data; checking an identification number input from the external unit in the IC card by comparison with a personal identification number stored in the memory in the IC card, upon determination that accurate writing occurred; and constantly responding to the external unit that an identification error has occurred upon determination that accurate writing has not occurred.
Claim 7
Independent Claim
129 words
A method of checking a personal identification number in an IC card, said method comprising: writing predetermined dummy data in a memory in an IC card in response to a command to check a personal identification number input to the IC card from an external unit; reading out from the memory the dummy data written into the memory; determining whether accurate writing occurred by comparing the read-out dummy data with the written-in dummy data; checking an identification number input from the external unit in the IC card by comparison with a personal identification number stored in the memory in the IC card, upon determination that accurate writing occurred; and constantly responding to the external unit that an identification error has occurred upon determination that accurate writing has not occurred.
Claim 8
Dependent Claim
30 words
The method according to claim 5, wherein the dummy data written in the memory comprises fixed data for verifying the reading-out operation and variable data for verifying the writing-in operation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-11-21 | 1998-05-23 | 1998-11-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-11-21 | 2002-05-23 | 2002-11-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-11-21 | 2006-05-23 | 2006-11-22 | $7700.00 | Window Closed / Lapsed |