JPH0235605A - System for reading magnetic stripe - Google Patents

Abstract

PURPOSE:To read magnetic stripes having various kinds of recording density with one magnetic stripe reader by deciding the recording density by the magnetic stripe reader itself and making the characteristic of a read circuit fit for it. CONSTITUTION:The above reader is provided with a magnetic head 14 and the read circuit. It measures the time per bit of a signal outputted from the magnetic head at the time of reading the magnetic stripe and calculates the recording density of the magnetic stripe from the bit time so as to set the characteristic of the read circuit according to the recording density. Thus, the plural kinds of magnetic stripes having different kinds of recording density can be read with one magnetic stripe reader.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a magnetic stripe reading method for passbook printers, etc.
The present invention relates to a magnetic stripe reading method that can be supported by as many devices as possible.

[Prior art]

The magnetic stripes of bankbooks used in banks and the like have different recording densities and formats depending on the user. Also, the same user is increasing the recording density of the magnetic stripe in order to improve system accuracy and increase the amount of information. Therefore, the same system may read magnetic stripes with different recording densities due to cooperation among users or by changing the recording density of the magnetic stripe of the passbook used in the system.

In addition, conventional magnetic stripe reading devices are equipped with a demodulation circuit that uses a differential amplifier, and when reading many types of magnetic stripes, the communication line connected to the host device, the received recording density information, or the information on the medium. The read amplifier characteristics and read speed were changed according to the recording density information.

In such a method, for one type of recording density/user,
Recording density information can be set in advance, but in the case of various recording densities/users, the recording density is assumed. Therefore, if the assumed recording density is different, a retry is performed.

Also, as a method to identify the type of magnetic stripe,
For example, as described in Japanese Unexamined Patent Publication No. 132288/1988, it is possible to determine whether an inserted magnetic card has a single track or a multi-track by detecting the presence or absence of an output signal of a magnetic stripe track. A method has been proposed for identifying the type of magnetic card. However, with this method, it is difficult to identify the recording density.

[Problem to be solved by the invention]

The above-mentioned conventional technology uses a demodulation circuit using a differential amplifier, but while this demodulation circuit has a simple circuit configuration and is inexpensive, it cannot This results in distortion of the demodulated waveform and incompatibility of sampling, resulting in abnormal reading.

Therefore, in a device that handles many types of magnetic stripes with different recording densities, based on recording density information given from external input means or recording density information provided on the medium,
This was handled by changing the characteristics of the reading circuit.

However, this method is only effective if the recording density of the medium is clear before performing a read operation.

Reading was difficult when the recording density was unclear.

The purpose of the present invention is to improve these problems.

By determining the recording density on the magnetic stripe reader itself without requiring recording density information from the host device, and by matching the characteristics of the reading circuit, it is possible to read magnetic stripes with many different recording densities with one device. The objective is to provide a possible magnetic drive reading method.

[Means to solve the problem]

In order to achieve the above object, the magnetic stripe reading method of the present invention includes a magnetic head and a reading circuit (differential amplifier,
A magnetic stripe reading device that is equipped with a demodulation circuit) and reads data written on a magnetic stripe includes a means (timer) for measuring the time per bit of the signal output by the magnetic head when reading the magnetic stripe, and a means (timer) for measuring the time per bit of the signal output by the magnetic head when reading the magnetic stripe. Means for calculating the recording density of magnetic stripe (
processor) and means (amplifier characteristic correction circuit) for setting the characteristics of the reading circuit according to its recording density,
By measuring the bit time of the magnetic stripe while reading data, calculating the recording density from that bit time, and setting the characteristics of the reading circuit according to the recording density, multiple types of magnetic stripes with different recording densities can be used. The feature is that the stripe is read by one magnetic stripe reader.

[Effect]

In the present invention, when reading a magnetic stripe, the recording density is calculated using the timing code of the magnetic stripe.

Typically, magnetic stripes are written in the format shown in FIG.

Among these, the starting code is 2. Data section 3. and the end code 4 is bit II OTr, as shown in part b of FIG.
II 1″″ and has frequency fluctuations, it is difficult to measure bit times of 1G to t. However, timing code 1 is as shown in part a of FIG.
Because it is a repetitive waveform consisting of a series of bits "0",
Measuring the bit time, ~t, is easy.

This allows you to read magnetic stripes.

Recording density is calculated using timing code 1.

Furthermore, since there is no frequency variation in timing code 1, the amount of distortion of the repetitive waveform remains the same even if the frequency-temporal matching of the differential amplifier is not achieved. Therefore, even if the frequency-time characteristics of the differential amplifier cannot be matched, the recording density calculation is not affected.

Utilizing this feature, by measuring the frequency at the beginning of reading the timing code 1, calculating the recording density, and matching the characteristics of the reading circuit, it is possible to correctly read the start code 2, data part 3, and end code 4. Can be done.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 4 is a block diagram of a magnetic stripe reader according to an embodiment of the present invention.

The magnetic stripe reading device of this embodiment has a processor 11.
, motor control circuit 12. Motor 13, magnetic head 14.
Differential amplifier 15, demodulation circuit 16° memory 17. Amplifier characteristic correction circuit 18. and a bit time measurement timer 19.

The processor 11 rotates the motor 13 through the motor control circuit 12 to move the magnetic head 14 along the magnetic stripe at a constant speed. As a result, the magnetic head 1
Processor 11 reads the signal output from 4 through differential amplifier 15 and demodulation circuit 16.

At the same time, the processor 11 calculates the recording density from the bit time determined by the bit time measurement timer 19, takes in a correction value matching the recording density from the memory 17, and operates the amplifier correction circuit 18.

Note that the bit time measurement timer 19 may be a software timer or a hardware timer.

Figure 1 shows calculation of recording density in one embodiment of the present invention.
and a flowchart showing correction of the reading circuit.

In this embodiment, when the first bit of the timing code is detected after reading is started (101), the bit time measurement timer 19 is started (102).

Next, the second bit is detected (103) and the bit time measurement timer 19 is stopped (104).

Next, the recording density is calculated from the measurement time of the bit time measurement timer 19 (1 o 5), a correction value corresponding to this value is selected (106), and the amplifier characteristic correction circuit 18 is activated.
Then, the demodulation circuit 16 is set (107).

As a result, the signal defined without distortion by the differential amplifier 15 is correctly sampled by the demodulation circuit 16, and data is read normally (108, 109).

In this embodiment, the time is measured only once, but reliability can be further improved by increasing the number of measurements by measuring the bit time of the second and subsequent bits.

In addition, in this embodiment, a method is adopted in which the magnetic head is moved to read the magnetic stripe and the differential amplifier is corrected. Even when a method is adopted in which the recording density is made to correspond to the recording density, writing can be performed at the recording density determined in the same manner.

In this manner, reading of various types of magnetic stripes can be supported by self-determining the recording density.

〔Effect of the invention〕

According to the present invention, since the reading circuit calculates the recording density and can handle magnetic stripes with various recording densities, there is no need to receive recording density information using a communication line with a host device, and the recording density can be managed. is not necessary.

Further, even if an apparatus does not have a means for inputting recording density information, it is possible to support magnetic stripes having various recording densities with one apparatus.

Furthermore, it is possible to support magnetic drives with various recording densities without setting recording density information on the media.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing recording density calculation and reading circuit correction in an embodiment of the present invention, FIG. 2 is a diagram showing the configuration of a magnetic stripe format in an embodiment of the present invention, and FIG. FIG. 4 is a timing chart for reproducing a magnetic stripe in an embodiment of the present invention, and is a configuration diagram of a magnetic stripe reading device in an embodiment of the present invention. 1: Timing code, 2: Start code 73: Data part, 4
: End code, 11: Processor, 12: Motor control circuit, 13: Motor, 14: Magnetic head, 15: Differential amplifier, 16: Demodulation circuit, 17: Memory, 18: Amplifier characteristic correction circuit, 19: Bit time measurement timer .

Claims (1)

[Claims] 1. In a magnetic stripe reading device that includes a magnetic head and a reading circuit and reads data written on a magnetic stripe, means for measuring the time per bit of a signal output by the magnetic head when reading the magnetic stripe;
The device includes means for calculating the recording density of the magnetic stripe from the bit time, and means for setting the characteristics of the reading circuit according to the recording density, and measures the bit time of the magnetic stripe while reading data, and calculates the recording density of the magnetic stripe based on the bit time. By calculating the recording density from time and setting the characteristics of the reading circuit according to the recording density, a single magnetic stripe reader can read multiple types of magnetic stripes having different recording densities. magnetic stripe reading method.