JPH0242823A - anti-theft device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an anti-theft device for preventing the theft of audio equipment and the like.

BACKGROUND OF THE INVENTION Conventionally, this type of anti-theft device is equipped with a microprocessor and a non-volatile memory for pre-storing a code number, and when the power to the audio equipment etc. is turned off and then turned on again, The anti-theft mode is not canceled and the audio equipment etc. are not operated unless the anti-theft mode is switched to and a number corresponding to the code number registered in the non-volatile memory is entered by key operation.

Problems to be Solved by the Invention However, in the conventional anti-theft device described above, an unauthorized user can easily obtain the code number registered in the non-volatile memory using a reading device. There is a problem in that the anti-theft mode can be canceled by key-operating the number.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, it is an object of the present invention to provide an anti-theft device in which a code number stored in a non-volatile memory cannot be easily obtained by an unauthorized user.

Means for Solving the Problems In order to achieve the above object, the present invention stores in advance code numbers corresponding to multiple digit numbers for canceling the anti-theft mode at random addresses in a non-volatile memory. At the same time, a code number different from the code number is stored in an area other than the area where the code number is stored.

Effect of the Invention With the above configuration, even if an unauthorized user reads data in the nonvolatile memory using a reading device, he or she cannot easily learn which code number is the code number for canceling the anti-theft mode. .

EXAMPLES Hereinafter, the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of an anti-theft device according to the present invention and an audio device using this anti-theft device, and FIG.
Fig. 1 is an explanatory diagram of the storage contents of the nonvolatile memory, and Fig. 3 is as follows.
2 is a flowchart for explaining the operation of the anti-theft device shown in FIG. 1. FIG.

In FIG. 1, 1 is a receiving antenna of the audio equipment, 2 is a radio receiving section 2a that converts the frequency of the signal received via the receiving antenna 1, and a tape playback section that plays back the signal recorded on the tape. 2b, the main body of the audio equipment is roughly constituted by a power amplifier 2c that amplifies the low frequency signals from the radio receiving section 2a and the tape playback section 2b; and 3 is a speaker that converts the signal from the power amplifier 2c into electroacoustic.

Reference numeral 4 denotes a non-volatile memory in which code numbers etc. for canceling the anti-theft mode are stored in advance, and as shown in FIG. 2, addresses rOJ, "1", "
For example, code numbers "ollo", "1oo1", and "ollo" are used for "2", "3", "4" to "10", respectively.
, "0o1o", "100o", and "olol" are registered in advance.

5 is a processor that executes processing to prevent theft of the audio equipment as described later; 6 is a key input unit for inputting numbers corresponding to a code number for canceling the anti-theft mode; The processor 6 is supplied with power by a power switch (not shown) of the audio equipment.

Note that the code number for the nonvolatile memory 4 is, for example, R.
It is registered by operating the OM writer or the key input unit 6, and for addresses "1" to "4", the code numbers corresponding to the input digits are stored sequentially in the addresses "1" to "4". Ru.

Next, the operation of the above embodiment, particularly the operation of the microprocessor 6, will be explained with reference to FIG.

When power is supplied by the power switch of the audio equipment in step 11.12, the process proceeds to step 13, where it is determined whether the power has been temporarily removed from the audio equipment and reconnected, and if the power has not been removed, the step is directly performed. Proceed to step 17 and operate the audio equipment normally.

On the other hand, if the power supply is once removed from the audio equipment, the process branches to step 14, and the audio equipment enters an anti-theft mode in which the audio equipment is not operated.

In the subsequent step 16, each digit of the number inputted from the key input section 6 is converted into a code number, and these code numbers and non-volatile memory 40 addresses "4", "3", " The code numbers stored in “2” and “1” are “10oO”, “oolo”, and “ol”.
Lo" and "1001" are compared, and if they are correct, the process proceeds to step 17 to cancel the anti-theft mode; on the other hand, if they are incorrect, the process returns to step 14.

Therefore, according to the above embodiment, the code numbers stored in addresses other than addresses "1", "2", "3", and "4" of the nonvolatile memory 4 are the code numbers for canceling the anti-theft mode. In addition, the code numbers for canceling the anti-theft mode are randomly stored at addresses "4", "3", "2", and "1", so an unauthorized user can access the non-volatile memory 4.
Even if the data is read, the code number to cancel the anti-theft mode cannot be easily obtained.

In the above embodiment, the code number for canceling the anti-theft mode is stored in the address "1" sequentially starting from the address "4", but as shown in FIG. ”
, "2", and "o", it becomes more difficult for an unauthorized user to obtain the correct code number.

DETAILED DESCRIPTION OF THE INVENTION As described in detail, the present invention stores code numbers corresponding to multiple digit numbers for canceling the anti-theft mode in advance at random addresses in a non-volatile memory, and Since a code number different from the above code number is stored in an area other than the area where the number is stored, even if an unauthorized user uses a reading device to read the data in the non-volatile memory, it will be difficult to identify which code number has been stolen. This has the effect that the code number for canceling the prevention mode cannot be easily obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of an anti-theft device according to the present invention and an audio device using this anti-theft device;
The diagrams are an explanatory diagram of the storage contents of the nonvolatile memory in Figure 1, and Figure 3.
1 is a flowchart for explaining the operation of the anti-theft device shown in FIG. 1, and FIG. 4 is an explanatory diagram showing another example of the storage contents of the nonvolatile memory shown in FIG. 1. 1... Receiving antenna, 2... Audio equipment body, 3...
- Speaker, 4... Non-volatile memory, 5... Microprocessor, 6... Key input unit. Name of agent: Patent attorney Shigetaka Awano and 1 other person
Figure 3Figure 2

Claims (1)

[Claims] A key input section for inputting a number corresponding to the code number and a code number corresponding to a plurality of digits for canceling the anti-theft mode in advance are stored in addresses in random order, and the code A nonvolatile memory stores a code number different from the code number in an area other than the area where the number is stored, and a nonvolatile memory that sequentially converts each digit into a code number when a number is input through the key input section. , means for canceling the anti-theft mode when each code number matches the code number for canceling the anti-theft mode.