JP2000298805A - Readout apparatus for magnetic recording medium, control method thereof, and recording medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine influences of an external noise in accordance with characteristics intrinsic to a magnetic patter such as an MICR character or the like, and give an accurate warning of occurrence of abnormal conditions in the magnetic pattern. SOLUTION: This apparatus includes a magnetic head 61 for reading out a magnetic pattern 71 on a recording medium 7, an interface 2 for communicating with a host apparatus 1, a detector 6 for detecting an external magnetic noise in the vicinity of the magnetic head 61, a comparator 5 for comparing the external magnetic noise detected by the detector 6 with an acceptable value for the external magnetic noise, a reporter 9 for giving a notice when the external magnetic noise exceeds an acceptable value thereof based on the comparison result of the comparator 5, a command interpretation section 3 for interpreting a command received from the host apparatus 1, and an acceptable value setting section 4 for setting, when the command interpretation section 3 interprets a predetermined command, an acceptable value for the external magnetic noise to be compared by the comparator 5 in accordance with the predetermined command.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for reading a magnetic pattern from a recording medium on which a magnetic pattern such as a MICR character is recorded. The present invention relates to a technique for notifying the user or the like of this.

[0002]

2. Description of the Related Art Conventionally, attempts have been made to detect and notify an operator when an externally induced noise is applied to an apparatus for reading MICR characters or the like. For example, Japanese Patent Application Laid-Open No. 9-245119 discloses M
Prior to reading the certificate in which the ICR character is recorded, a signal guided from the outside to the magnetic head is detected, and when the signal reaches a predetermined level, the display element is immediately turned on or transmitted to the host device through the interface. A technique of notifying an operator or the like by the notification of the above is disclosed.

However, in this technique, since the measurement result of the induced signal due to the external magnetic noise is compared with a certain allowable value, the external magnetic noise is in a range that does not affect the recognition of the MICR character. In some cases, a false alarm was issued. That is, since there are a plurality of standards for magnetic patterns such as MICR characters, and the noise resistance differs for each standard of the magnetic pattern, the allowable value of the external magnetic noise also greatly differs for each standard. Therefore, if the threshold value for determining the extraneous magnetic noise abnormality is uniquely determined, such a problem occurs.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make the influence of extraneous magnetic noise unique to the type of magnetic pattern such as MICR characters recorded on a recording medium. It is an object of the present invention to provide a magnetic recording medium reading apparatus and a control method therefor, which can make a judgment according to the characteristics of the magnetic recording medium and can give an accurate warning of occurrence of abnormal magnetic pattern reading due to external magnetic noise.

[0005]

In order to achieve the above object, a magnetic recording medium reader according to the present invention reads a magnetic pattern on a recording medium using a magnetic head. And a detector for detecting external magnetic noise near the magnetic head; a comparator for comparing the external magnetic noise detected by the detector with an allowable value of the external magnetic noise; Based on the comparison result of the devices, a notifier for notifying when the external magnetic noise exceeds an allowable value of the external magnetic noise, and a command interpretation for interpreting a command received from the host device via the interface unit. And when the command interpreter interprets a predetermined command, the comparator compares the command in response to the predetermined command. And having a permissible value setting unit for setting the allowable value of the external magnetic noise.
This makes it possible to set the allowable value of the external magnetic noise suitable for the magnetic pattern according to the magnetic pattern that the host device makes the magnetic recording medium reading device read, thereby improving reliability. It is possible to perform notification of an extraneous magnetic noise abnormality having a high level of noise.

In this case, the permissible value setting unit has a memory for storing a plurality of permissible values of the external magnetic noise, and according to the predetermined command, one permissible value from the plurality of permissible values. May be selected and set. Accordingly, when reading a standardized magnetic pattern, the magnetic recording medium reading apparatus prepares in advance the permissible values of the external magnetic noise corresponding to these, and the host apparatus selects this. Is possible, and the load on the host device is reduced. Further, it is possible to set an allowable value in consideration of the characteristics unique to the magnetic recording medium reading device, and it is possible to perform more reliable notification of the external magnetic noise abnormality.

[0007] Alternatively, the allowable value setting section may set the allowable value to a value specified by the predetermined command in response to the predetermined command. Thereby, it is possible to set the allowable value of the external magnetic noise according to the characteristics of the read error rate required by the host device, and it is possible to perform notification about the external magnetic noise abnormality suitable for the application of the host device. Become.

In these cases, it is preferable that the allowable value setting unit includes an allowable value storage unit that stores the allowable value of the external magnetic noise in association with the type of the magnetic pattern. As a result, the allowable value of the external magnetic noise specified by the command from the host device can be stored in association with the type of the magnetic pattern selected at the time of interpreting the command. By doing so, it is possible to set a corresponding allowable value of the external magnetic noise.

Further, in these cases, it is desirable that the predetermined command is a command for specifying the type of the magnetic pattern. Thus, it is possible to set the allowable value of the external magnetic noise corresponding to the type of the magnetic pattern only by specifying the type of the magnetic pattern, which is convenient.

The control method of the magnetic recording medium reading apparatus of the present invention is also specified by the same items as described above, and has the same functions and effects. Further, the computer-readable recording medium of the present invention also includes:
It stores a computer program for realizing the above-described method of controlling the magnetic recording medium reading device by a computer, and has the same operational effects as those described above.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a block diagram showing a basic configuration of a magnetic recording medium reading apparatus according to a first embodiment of the present invention. The recording medium 7 is provided with a magnetic pattern 71. The magnetic pattern 71 may be printed on the recording medium 7 using magnetic ink or the like, or may be recorded on a magnetic recording medium or the like applied or affixed on the recording medium by a method such as longitudinal recording or perpendicular recording. It may be.

The recording medium 7 is moved relative to the magnetic head 61 by a transport mechanism 8 having transport rollers and a stepping motor for driving the same. Note that the magnetic head 61 may be mounted on a carriage and move with respect to the recording medium, and the drive source of the transport roller may be a DC motor having a positioning mechanism such as an encoder.

The detecting section 6 has a magnetic head 61 and an amplitude detector (not shown). The magnetic head 61 has a magnetic gap substantially perpendicular to the recording medium conveyance direction, and originally detects a change in magnetic flux due to the movement of the magnetic pattern 71 and outputs a current corresponding thereto. The magnetic gap length in this case is set according to the frequency of the magnetic signal to be reproduced. When reading a magnetic pattern that requires re-magnetization, such as MICR characters, a re-magnetization magnet (not shown) is used, or a self-bias type having an electromagnet for forming a bias magnetic field in the magnetic head 61 is used. .

The magnetic pattern 7 generated by the magnetic head 61
The current signal corresponding to 1 is converted into a voltage signal by an amplitude detector (not shown), amplified, and then its amplitude is detected. At this time, normally, a DC component is removed by AC coupling, and an appropriate bias voltage is applied. The amplification is performed by an operational amplifier. After the analog-to-digital conversion, the amplitude is detected by a microprocessor at a predetermined cycle. This detection value is stored in a RAM described later.

The detecting section 6 detects an electric signal output from the magnetic head 61 when the magnetic head 61 is not reading the magnetic pattern 71, that is, the amplitude of the external magnetic noise by an amplitude detector. As will be described later, the detection unit 6 includes a magnetic head 61, a microprocessor and a ROM storing a program that defines the operation of the microprocessor, and acquires the output of the amplitude detector at a predetermined timing. The above functions are realized.

The amplitude of the extraneous magnetic noise obtained by this operation is compared by a comparator 5 with a predetermined allowable value.
In this example, the comparison means comparing the set allowable value of the external magnetic noise with the measured value of the external magnetic noise amplitude. Specifically, for example, the read signal amplitude 2
0% is set as the allowable value of the external magnetic noise amplitude, and a process of comparing the allowable value with the measured value of the external magnetic noise amplitude is performed. In addition,
It is effective to set not only the amplitude value but also, for example, the allowable frequency of the external magnetic noise. That is, if the read signal frequency and the extraneous magnetic noise frequency are sufficiently separated,
This is because external magnetic noise can be removed by a digital filter operation or the like by a microprocessor.

The annunciator 9 is provided in the apparatus according to the comparison result of the comparator 8, that is, whether or not the external magnetic noise exceeds the allowable value, depending on whether or not the external magnetic noise exceeds the allowable value. The user is notified by lighting or blinking an indicator such as an LED. Further, the host device is notified via the interface unit 2. If the external magnetic noise does not exceed the allowable value, the notification may not be performed. Further, the annunciator 9 is not limited to simply announcing, and may involve an abnormal process such as a stop or prohibition of the magnetic pattern reading process and an ejection of the recording medium 1.

When the interface unit 2 receives data from the host device 1, the command interpreting unit 3 compares the data with a predetermined command code or a command code sequence, and interprets the data as a command. For example, when the data is a command for setting an allowable value of extraneous magnetic noise, the command is notified to the allowable value setting unit 4.

When the command interpreted by the command interpreting unit 3 is a predetermined command such as a command for specifying or selecting the type of the magnetic pattern, the allowable value setting unit 4 responds to the command by using the predetermined command. Set the allowable value of the external magnetic noise used in. In this example, the permissible value transmitted in the form of the parameter of the command or the like is transmitted to the comparison unit 5 and is provided to the comparison unit 5 for comparison processing. As described above, the allowable value desirably includes both the frequency component and the amplitude, but may include either one.

The interface unit 2 sends the data received from the host device 1 to the command interpreting unit 3, and also sends a notification about external magnetic noise from the notifying unit 9 and status information of the device to the host device 1.

FIG. 2 is a block diagram showing a control circuit of the magnetic recording medium reading apparatus according to the first embodiment of the present invention. The control system of the command interpreting section 3, the allowable value setting section 4, the comparing section 5, the notifying section 9 and the detecting section 6 is mainly a CPU 3
1, a ROM 32 and a RAM 33. That is, the CPU 31 performs the above-described processing according to a control program stored in the ROM and / or the RAM.

When the notification unit 9 notifies the user of the apparatus by blinking the display 92 or the like, a predetermined drive signal is output from the I / O circuit 91. If the driving capability of the I / O circuit is not sufficient, the driving is performed via a driver circuit such as a power transistor (not shown).

When the detecting unit 6 detects external magnetic noise, the CPU 31 is connected to a magnetic head connection terminal 63 via an analog-to-digital converter (hereinafter abbreviated as ADC) 62. At a predetermined cycle. When the output signal level of the magnetic head 61 is low, an AC amplifier is used.

When the interface unit 2 communicates with the host device 1, the communication is performed via an interface element 21 such as an RS232C driver and a universal asynchronous receiver / transmitter (UART).

The control program of the CPU 31 is stored in a recording medium such as the floppy disk 10 or the hard disk 11 and is stored in the interface element 2.
1 can be installed in the RAM 65 and executed. It is also possible to use the Internet server 12 as a recording medium and install the control program via the recording medium. Further, the ROM 66 may be an EEPROM, into which the control program may be installed.

Next, an operation of the magnetic recording medium reading apparatus according to the first embodiment of the present invention and a control method thereof will be described with reference to a flowchart. FIG. 3 is a flowchart showing the command processing of the magnetic recording medium reading device according to the first embodiment of the present invention. The command processing is performed by the command interpreting unit 3 when the interface unit 2 receives data from the host device 1 in principle. However, if data is received from the host device 1 during interpretation by the command interpreting unit 3 and processing of the command,
The data is temporarily stored in a reception buffer or a command buffer provided in the RAM 33, and is read out and processed in the order of storage.

In step S31, the command is interpreted, and if it is determined that the command is a command for setting an allowable value of extraneous magnetic noise, the above-described allowable value setting process is performed in step S32. On the other hand, if it is determined in step S31 that the command is a command other than the command for setting the allowable value of the external magnetic noise, the process proceeds to step S33.
Performs a process corresponding to the command. After the command processing is completed, processing for checking the state of the apparatus such as the power supply voltage is performed.

FIG. 4 is a flowchart showing a process of comparing the detected value of the external magnetic noise with the allowable value of the magnetic recording medium reading apparatus according to the first embodiment of the present invention. In the present embodiment, the comparison processing between the detected value of the external magnetic noise and the allowable value is performed constantly or at predetermined time intervals.
The result is stored in the RAM 33 as a flag described later. In step S41, the CPU 31 sets the ADC 62
The external magnetic noise is taken in through such as. As described above, this capture is performed by the magnetic head 61 using the magnetic pattern 71.
In a state where a read signal is not generated due to relative movement with respect to the above, this is performed by taking in amplitude data a predetermined number of times at a predetermined cycle. The read data is stored in a predetermined area in the RAM 65 in the form of amplitude data for each predetermined cycle.

This read data is compared with the external magnetic noise allowable value set in the external magnetic noise allowable value setting process in step S42. The allowable value of the external magnetic noise is, for example, about 20% of the maximum value (PP value) obtained by subtracting the minimum value from the maximum value of the magnetic pattern read signal amplitude data according to the magnetic pattern to be read. Levels are used. Further, a frequency range, for example, one octave away from the frequency range of the magnetic pattern read signal may be set as the allowable value of the external magnetic noise. That is, in this range, the external magnetic noise can be removed by the filtering process regardless of the amplitude of the external magnetic noise.

If it is determined in step S42 that the extraneous magnetic noise exceeds the allowable value, the process proceeds to step S42.
At 43, the "external magnetic noise abnormality flag" is set, and the process ends. If it is determined in step S42 that the external magnetic noise does not exceed the allowable value, the "external magnetic noise abnormality flag" is reset in step S44, and the process ends. This flag is referred to in an external magnetic noise detection result notification process described later.

FIG. 5 is a flowchart showing a process of informing the external magnetic noise detection result of the composite magnetic recording medium reader according to the first embodiment of the present invention. Such notification processing is performed subsequent to the above-described comparison processing, but may be started at another timing. Step S51
Is checked, and if the flag is not set, a notification to the effect that the external magnetic noise is normal is transmitted to the host device 1 via the interface element 21 in step S52. If the flag has been set, a notification that the external magnetic noise is abnormal is made in step S53. At the same time as this notification, error processing such as ejection of the recording medium or display of a warning on a display of the apparatus may be performed. When the external magnetic noise is within the allowable range, the notification is not performed, that is, step S52 can be omitted.

(Second Embodiment) A magnetic recording medium reading apparatus according to a second embodiment of the present invention is a composite magnetic recording medium according to the first embodiment described above except for processing for setting an allowable value of extraneous magnetic noise. Since the processing is the same as that of the reading apparatus, only the processing will be described, and other description will be omitted.

FIG. 6 is a diagram showing an allowable value table used in an external magnetic noise allowable value setting process of the magnetic recording medium reading apparatus according to the second embodiment of the present invention.
In the allowable value setting process in the present embodiment, the command interpreted by the command interpreting unit 3 specifies the type of the magnetic pattern,
Or, in the case of a command for selection, the type of the magnetic pattern selected by the command is input to the allowable value table, and the allowable value of the external magnetic noise corresponding to the type of the magnetic pattern is output. Is set as the allowable value of the external magnetic noise used in the comparison unit 5.
Note that, as described above, the allowable value desirably includes both the frequency component and the amplitude, but may include either one. It is desirable that the allowable value table stores in advance an allowable value corresponding to the characteristics of the magnetic recording medium reading circuit of the apparatus.

(Third Embodiment) A magnetic recording medium reader according to a third embodiment of the present invention is different from the composite magnetic recording medium reader according to the first or second embodiment except for the command processing. Since this is the same, only the difference will be described, and the other description will be omitted.

FIG. 7 is a flowchart showing the command processing of the magnetic recording medium reading apparatus according to the third embodiment of the present invention. Also in the present embodiment, the command processing is
In principle, this is performed by the command interpreting unit 3 when the interface unit 2 receives data from the host device 1. However, when data is received from the host device 1 during the interpretation by the command interpreting unit 3 and the processing of the command, the data is temporarily stored in a receiving buffer or a command buffer provided in the RAM 33, and is stored in the order of storage. Read and processed.

In step S71, the command is interpreted, and if it is determined that the command is a command for setting an allowable value of extraneous magnetic noise, the above-described allowable value setting process is performed in step S72. In step S73, the above-described allowable value table is updated. In this processing, according to the type of the magnetic pattern selected at the time when the command for setting the allowable value of the extraneous magnetic noise is interpreted, the corresponding allowable value in the allowable value table is set to the command or its parameter. Update to the value set in. That is, the permissible value table is recreated.
On the other hand, if it is determined in step S71 that the command is a command other than the command for setting the allowable value of the extraneous magnetic noise, a process corresponding to the command is performed in step S73. After the command processing is completed, processing for checking the state of the apparatus such as the power supply voltage is performed.

The embodiment of the present invention has been described above.
The present invention is not limited to this, but includes various changes and modifications made within the scope obvious to those having ordinary knowledge in the art to which the present invention pertains from the above description.

[0038]

As described above, the magnetic recording medium reader according to the present invention is a magnetic recording medium reader for reading a magnetic pattern on a recording medium using a magnetic head. A detector that detects external magnetic noise near the magnetic head, a comparator that compares the external magnetic noise detected by the detector with an allowable value of the external magnetic noise, and a comparison result of the comparator. A notifier for notifying when the extraneous magnetic noise exceeds an allowable value of the extraneous magnetic noise, a command interpreter for interpreting a command received from the host device via the interface unit, and the command interpreter Interprets a predetermined command, the external magnetic noise to be compared in the comparator according to the predetermined command. And a tolerance value setting unit for setting a tolerance value of the external magnetic noise according to the magnetic pattern to be read by the magnetic recording medium reading device by the host device. Can be set, and it is possible to perform a more reliable notification of the extraneous magnetic noise abnormality.

In this case, the permissible value setting unit has a memory for storing a plurality of permissible values of the external magnetic noise, and according to the predetermined command, one permissible value from the plurality of permissible values. When reading a standardized magnetic pattern, an allowable value of external magnetic noise corresponding to these is prepared in advance on the magnetic recording medium reading apparatus side, and This can be selected, and the load on the host device is reduced. Further, it is possible to set an allowable value in consideration of the characteristics unique to the magnetic recording medium reading device, and it is possible to perform more reliable notification of the external magnetic noise abnormality.

Further, instead of the above, the permissible value setting unit sets the permissible value to a value specified by the predetermined command in response to the predetermined command. It is possible to set the allowable value of the external magnetic noise according to the characteristic of the error rate, and it is possible to notify the external magnetic noise abnormality suitable for the application of the host device.

In these cases, the allowable value setting unit has an allowable value storage unit for storing the allowable value of the external magnetic noise in association with the type of the magnetic pattern. The permissible value of the external magnetic noise can be stored in correspondence with the type of the magnetic pattern selected at the time of interpreting the command, and thereafter, the permissible value of the external magnetic noise can be stored simply by selecting the magnetic pattern. You can set a value.

Further, in these cases, since the predetermined command is a command for specifying the type of magnetic pattern, it is only necessary to specify the type of magnetic pattern and to set an allowable value of the external magnetic noise corresponding thereto. Can be
It is a convenience.

The control method of the magnetic recording medium reading apparatus of the present invention is also specified by the same items as described above, and has the same functions and effects. Further, the computer-readable recording medium of the present invention also includes:
It stores a computer program for realizing the above-described method of controlling the magnetic recording medium reading device by a computer, and has the same operational effects as those described above.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a basic configuration of a magnetic recording medium reading device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control circuit of the magnetic recording medium reading device according to the first embodiment of the present invention.

FIG. 3 is a flowchart showing command processing of the magnetic recording medium reading device according to the first embodiment of the present invention.

FIG. 4 is a flowchart illustrating a comparison process between a detected value of an external magnetic noise and an allowable value of the magnetic recording medium reading device according to the first embodiment of the present invention.

FIG. 5 is a flowchart showing an external magnetic noise detection result notification process of the composite magnetic recording medium reading device according to the first embodiment of the present invention.

FIG. 6 is a diagram showing an allowable value table used in an external magnetic noise allowable value setting process of the magnetic recording medium reader according to the second embodiment of the present invention.

FIG. 7 is a flowchart illustrating a command process of a magnetic recording medium reading device according to a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Host apparatus 2 ... Interface part 3 ... Command interpretation part 4 ... External magnetic noise allowable value setting part 5 ... Comparison part 6 ... Detection part 7 ... Recording medium 8. ..Transport mechanism 9 ... Notification unit 61 ... Magnetic head 71 ... Magnetic pattern (MICR characters)

Claims (15)

[Claims] 1. A magnetic recording medium reader for reading a magnetic pattern on a recording medium using a magnetic head, comprising: an interface unit for communicating with a host device; and a detector for detecting external magnetic noise near the magnetic head. A comparator that compares the extraneous magnetic noise detected by the detector with an allowable value of the extraneous magnetic noise; and, based on a comparison result of the comparator, the extraneous magnetic noise exceeds the allowable value of the extraneous magnetic noise. An alarm that notifies when the command is received, a command interpreter that interprets a command received from the host device via the interface unit, and a command that is interpreted by the command interpreter when the command is interpreted. An allowable value setting unit for setting an allowable value of the extraneous magnetic noise to be compared in the comparator. Magnetic recording medium reader. 2. The magnetic recording medium reading device according to claim 1, wherein the permissible value setting unit has a memory for storing a plurality of permissible values of external magnetic noise, and the plurality of permissible values are set according to the predetermined command. A magnetic recording medium reading apparatus, wherein one of the allowable values is selected and set. 3. The magnetic recording medium reading device according to claim 1, wherein the allowable value setting unit sets the allowable value to a value specified by the predetermined command in response to the predetermined command. A magnetic recording medium reading device characterized by the above-mentioned. 4. The magnetic recording medium reading device according to claim 1, wherein the allowable value setting unit stores the allowable value of the external magnetic noise in association with the type of the magnetic pattern. A magnetic recording medium reader having a value storage unit. 5. The magnetic recording medium reading device according to claim 1, wherein the predetermined command is a command for specifying a type of a magnetic pattern. 6. A method for controlling a magnetic recording medium reading device for reading a magnetic pattern on a recording medium by using a magnetic head, wherein a step of performing communication with a host device and a step of detecting external magnetic noise near the magnetic head. Comparing the external magnetic noise detected in the detection step with the allowable value of the external magnetic noise, based on the comparison result in the comparing step, the external magnetic noise exceeds the allowable value of the external magnetic noise. Notifying if the command has been received, interpreting a command received from the host device via the interface unit, and responding to the predetermined command when a predetermined command is interpreted in the command interpreting step. Setting a permissible value of the extraneous magnetic noise compared in the comparing step. Control method for a magnetic recording medium reader. 7. The control method for a magnetic recording medium reading device according to claim 6, wherein in the allowable value setting step, an allowable value of a plurality of external magnetic noises stored in a memory is determined in accordance with the predetermined command. And a method for selecting and setting one allowable value. 8. The control method for a magnetic recording medium reading device according to claim 6, wherein in the allowable value setting step, the allowable value is changed to a value specified by the predetermined command in response to the predetermined command. A method for controlling a magnetic recording medium reading device, wherein the setting is performed. 9. The control method for a magnetic recording medium reading device according to claim 6, wherein the allowable value setting step sets the allowable value of the external magnetic noise in accordance with the type of the magnetic pattern. A method for controlling a magnetic recording medium reading device, comprising a step of storing. 10. The control method for a magnetic recording medium reading device according to claim 6, further comprising a step of setting a type of said magnetic pattern according to said predetermined command. A method for controlling a magnetic recording medium reader. 11. A computer-readable recording medium storing a program for realizing a control method of a magnetic recording medium reading device for reading a magnetic pattern on a recording medium using a magnetic head, wherein the composite magnetic recording medium is provided. The method of controlling the reading device includes: a step of performing communication with a host device; a step of detecting external magnetic noise near the magnetic head; and a step of detecting the external magnetic noise detected in the detecting step and an allowable value of the external magnetic noise. A step of comparing, based on a comparison result in the comparing step, a step of performing notification when the external magnetic noise exceeds an allowable value of the external magnetic noise, and receiving from the host device via the interface unit. When a predetermined command is interpreted in the command interpreting step, Setting an allowable value of the extraneous magnetic noise to be compared in the comparing step according to the predetermined command. 12. The recording medium according to claim 11, wherein
In the allowable value setting step of the control method of the magnetic recording medium reading device, one allowable value is selected from a plurality of allowable values of the external magnetic noise stored in the memory according to the predetermined command, and set. A recording medium characterized in that: 13. The recording medium according to claim 11, wherein
The recording medium, characterized in that in the allowable value setting step of the control method of the magnetic recording medium reading device, the allowable value is set to a value specified by the predetermined command in response to the predetermined command. 14. The recording medium according to claim 11, wherein the allowable value setting step of the control method of the magnetic recording medium reading device includes setting the allowable value of the external magnetic noise to the type of the magnetic pattern. A recording medium characterized by having a step of storing the information in accordance with (1). 15. The recording medium according to claim 11, wherein the control method of the magnetic recording medium reading device further includes a step of setting a type of the magnetic pattern according to the predetermined command. A recording medium characterized by the above-mentioned.