JPH0544716B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention records and reproduces information on a card (so-called IC card) that has a built-in semiconductor memory circuit.
Regarding IC card readers.

(Prior Art) IC card readers have been known for recording and reproducing information by bringing contact terminals into contact with contacts of an IC card. In this card reader, even if the electrical contact between the contact terminal and the contact point of the IC card is not made normally, or even if a different type of card other than an IC card is inserted, the abnormal state can be detected in advance. I had to turn it on and see if it worked.

(Problem to be Solved by the Invention) The conventional IC card reader described above does not have the ability to detect abnormal conditions such as insertion of a different type of card, so there may be cases where a different type of conductive object is inserted instead of the IC card. In this case, the power supply to the IC card places a burden on the shunted host, and depending on the material of the object, it can also cause a fire.

(Means for Solving the Problems) The present invention provides an IC card reader that records and reproduces information by bringing contact terminals into contact with contacts of an IC card.
a first contact terminal brought into contact with a first contact serving as a power supply terminal of the IC card; a first current limiting resistor connected between the first contact terminal and the power supply; A second contact terminal is connected between the first contact terminal and the ground point and is connected between the first contact terminal and the second contact terminal, which is connected between the first contact terminal and the ground point. a second resistor that detects the conduction state with the second contact;
The IC card is equipped with a level comparator that compares the detected value of the resistance with a preset reference value to determine whether the IC card has been properly inserted.

(Function) The conduction state between the first contact of the IC card and the second contact is detected by the second resistor, and the detected value of the second resistor is compared with a preset reference value by the level comparator. It is determined whether the IC card has been properly inserted. Therefore, even if a different type of conductive object is inserted in place of an IC card, the power supply will be connected to the different type of conductive object via the current limiting resistor, so there will be no risk of power shortening or fire. do not have. Furthermore, the structure is such that it can be determined whether the IC card has been properly inserted simply by checking the continuity between the first and second contacts, which serve as the power terminal and ground terminal of the IC card.
With a simple configuration, it is possible to determine whether an IC card has been properly inserted.

(Example) FIG. 1 shows a portion of an embodiment of the present invention.

In this embodiment, information is recorded and reproduced by bringing the contact terminal into contact with the contact point of the IC card.
The IC card reader is equipped with a means to determine whether or not the IC card has been properly inserted, and when the IC card is properly inserted into the card insertion section, the exposed contacts C1,
C2, C3, C4... are provided with contact terminals C11 and C4, respectively.
C12... are in contact with each other. The contact terminal C11 is connected to a power supply line Vcc of about 5V, for example, through a parallel circuit of a current limiting resistor RO and a switch SW.
It is connected to contact C1, which is the power terminal on the IC card. Contact terminal C12 is grounded,
Contact C2, which is the ground terminal on the IC card. Further, the contact terminal C11 is connected to the input terminal of the level comparator CP via a resistor R1, and is grounded via a resistor R2.

When the IC card is inserted into the card insertion part, the contacts C1, C2... of the IC card are connected to the contact terminals C11, C12.
The power is turned on after contacting ..., but at this time the switch SW is off and power is supplied from the power line Vcc to the contact C1 of the IC card via the current limiting resistor RO and the contact terminal C11. Contact C2 is grounded via contact terminal C12. The conduction state between the contact terminals C11 and C12 is the resistance R.
2, and the detected voltage is input to the level comparator CP via the resistor R1 and compared with preset reference voltages V _H and V _L . Here, the voltage at point A, that is, the detection voltage, falls within a certain range (between the reference voltages V _H and V _L ) when the IC card is properly inserted into the card insertion part, and falls outside the certain range in other cases. It slips off. The logic unit LG determines whether the IC card has been properly inserted into the card insertion section from the output signal of the level comparator CP, and sends a determination signal S.
1, S2 to the host side, and receives a control signal S3 from the host side to control the switch SW. In this case, the discrimination signal S1 is a signal indicating whether the voltage at point A is within a certain range between the reference voltages V _H and V _L , and the discrimination signal S2 is a signal indicating whether the voltage at point A is outside the above certain range. This is a signal indicating whether the voltage is higher than the reference voltage V _H or lower than the reference voltage V _L when the voltage is higher than the reference voltage V H or lower than the reference voltage V L. Further, the control signal S3 is a signal that turns the switch SW on/off according to the discrimination signal S1, and when the voltage at point A is within a certain range, the switch SW is turned on/off in accordance with the discrimination signal S1.
Switch SW is turned on, and when the voltage at point A is out of a certain range, the switch SW is turned off.

FIG. 2 shows the voltage at point A in various cases.

First, the contact terminals C11, C12... are connected to the contacts C1, C2 of the IC card by inserting the IC card backwards, etc.
If normal electrical contact is not made with ... (Case 1), the potential at point A becomes higher than the reference voltage _VH , and the discrimination signal S1 is connected to the contact terminals C11 and C12.
This indicates a poor connection between the contacts C1 and C2 of the IC card, and the determination signal S2 becomes high level. Control signal S3
becomes a switch-off signal according to the discrimination signal S1,
Logic circuit LG keeps switch SW off. In this case, an instruction (display) to reinsert the IC card is given by the determination signal S2 in the instruction section, and the IC card is
The card is re-inserted correctly. In addition, when the IC card is inserted correctly (case 2), contacts C1 and C2 of the IC card are connected in parallel with resistor R2, the voltage at point A enters between the reference voltages V _H and V _L , and the discrimination signal S1 is The normal connection between the contact terminals C11 and C12 and the contacts C1 and C2 of the IC card is shown. Therefore, after the control signal S3 is switched to the switch-on signal and the switch SW is turned on, information is recorded and reproduced on the IC card as in the conventional case. Also
When a conductive foreign object is inserted instead of an IC card (case 3), the contact terminals C11 and C1
2 is short-circuited and the voltage at point A is the reference voltage V _L
becomes lower, and the discrimination signal S1 reaches the contact terminal C11,
This indicates that the connection between C12 and the contacts C1 and C2 of the IC card is not normal, and the discrimination signal S2 becomes low level. Therefore, the alarm is activated by the discrimination signals S1 and S2 to issue an alarm such as a display prohibiting the use of the IC card, and the control signal S3 becomes a switch-off signal and the switch SW remains off. Therefore, the power supply will not be shunted, and a large current will not flow through the inserted foreign object due to the current limiting resistor RO, and no fire will occur.

Note that in the above embodiment, the signal S1 with the host side
~S3 may be eliminated and the switch SW may be automatically controlled internally.

(Effects of the Invention) As described above, according to the present invention, the first contact terminal that is brought into contact with the first contact serving as the power supply terminal of the IC card, and the first contact terminal that is connected between the first contact terminal and the power supply are a first current limiting resistor that is connected between the first contact terminal and the ground point; the first contact and the second
a level comparator that compares the detected value of the first resistor with a preset reference value to determine whether the IC card has been properly inserted; Even if a different type of conductive object is inserted in place of the IC card, the power supply will be connected to the different type of conductive object via the current limiting resistor, preventing the power supply from shortening or causing a fire. Occurrence can be prevented. Moreover, IC
Simply check the continuity between the first and second contacts, which are the card's power and ground terminals.
Since the configuration is configured to determine whether the IC card has been properly inserted, it is possible to reliably determine whether the IC card has been properly inserted with a simple configuration.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention, Figure 2 is a circuit diagram showing an embodiment of the present invention.
The figure is a diagram showing the voltage at point A in the same example. C1, C2...IC card contacts, C11, C
12...Contact terminal, CP...Level comparator.

Claims (1)

[Claims] 1. In an IC card reader that records and reproduces information by bringing a contact terminal into contact with a contact point of an IC card, the first contact terminal that is brought into contact with the first contact point that becomes the power terminal of the IC card among the contact terminals. 1 contact terminal, a first current limiting resistor connected between the first contact terminal and the power supply, and a second contact terminal of the contact terminal that serves as a grounding terminal of the IC card. a second contact terminal connected to and grounded; a first resistor connected between the first contact terminal and the ground point to detect a conduction state between the first contact and the second contact; An IC card reader comprising: a level comparator that compares the detected value of the first resistor with a preset reference value to determine whether the IC card has been properly inserted.