JPH0242825A - Robbery preventing device - Google Patents

Abstract

PURPOSE:To prevent a code for preventing mode release from being easily known with an unauthorized user by housing a different code number in an area excepting for an area, where the code number for robbery preventing mode release is housed in advance, in a non-volatile memory. CONSTITUTION:When a power source is re-connected after it is once separated from an acoustic equipment, operation is transited to a robbery preventing mode and respective numerals to be successively inputted from a key input part 6 are converted to the code numbers. Next, the respective code numbers and the code number, which is housed in a non-volatile memory 4, are compared according to an order which is programmed in advance. As a result, when the code number is correct, the robbery preventing mode is released and when the code number is wrong, dan unoperatable mode is obtained. In such a case, the code number to be different from the code number for robbery preventing mode release is housed to the area excepting for the area, in which the code number for robbery preventing mode release is housed, in the memory 4. Accordingly, even when the unauthorized user reads the data of the memory 4 by using a reader, it can not be easily known which code number releases the robbery preventing mode.

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 in which a code number is stored in advance. The anti-theft mode will not be canceled unless the number corresponding to the code number registered in the non-volatile memory is entered by key operation.
It is configured so that audio equipment etc. are not operated.

Problems to be Solved by the Invention However, in the above-mentioned conventional theft prevention device, an unauthorized user can easily obtain the code number registered in the non-volatile memory using the 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 a code number for canceling the anti-theft mode in a non-volatile memory in advance, and also stores a non-volatile memory in an area other than the area where the code number is stored. A code number different from the code number described above is stored in an area of the memory.

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 non-volatile memory, and Fig. 3 is as follows.
1 is a flowchart for explaining the operation of the anti-theft device shown in FIG. 1. In FIG. The main body of the audio equipment is generally composed of a radio receiving section 2a, a tape playback section 2b that plays back signals recorded on a tape, and a power amplifier 2c that amplifies low frequency signals from the radio reception section 2a and the tape playback section 2b. 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 1-0110J, 1'-1001J, and "01" are used for "2", "3", "4", and "10", respectively.
01 J, r 0111 j, rooloJ, “100
0" is 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 5 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.
The codes are 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 sequentially stored in addresses "4" to "1".

Next, the operation of the above embodiment, particularly the operation of the microprocessor 5, 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 removed from the audio equipment and reconnected, and if the power has not been removed, the power is directly connected to the audio equipment. 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 following step 15, each number input sequentially from the key input section 6 is converted into a code number, and each code number and the non-volatile memory address 40 are converted into a code number according to a pre-programmed order.
Code numbers "0010", "0111", [0101J, r stored in "4", "3", "2", "1"
1001J, and if it is correct, the process proceeds to step 17 to cancel the anti-theft mode, whereas if it is incorrect, the process returns to step 14.

Therefore, according to the above embodiment, code numbers stored at addresses other than addresses "4", "3", "2", and "1" of the nonvolatile memory 4 cancel the anti-theft mode. Since it is not a code number, even if an unauthorized user reads the data in the nonvolatile memory 4, he or she cannot easily obtain the code number for canceling the anti-theft mode.

DETAILED DESCRIPTION OF THE INVENTION As described above, the present invention stores a code number for canceling the anti-theft mode in a non-volatile memory in advance, and stores the code number in an area of the non-volatile memory other than the area where the code number is stored. Since a code number different from the code number is stored, even if an unauthorized user uses a reading device to read the data in the non-volatile memory, it is easy to know which code number is the code number for canceling the anti-theft mode. This has the effect that it cannot be known.

[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.
FIG. 1 is a flowchart for explaining the operation of the anti-theft device shown in FIG. 1... Receiving antenna, 2... Audio equipment body, 3...
- Speaker, 4... Non-volatile memory, 5... Microprocessor, 6 - Key input section.

Claims (1)

[Claims] A key input section for inputting a code number and a code number for canceling the anti-theft mode are stored in advance, and a code number different from the code number is stored in an area other than the area where the code number is stored. an anti-theft device comprising: a non-volatile memory for canceling the anti-theft mode; and means for canceling the anti-theft mode when a code number for canceling the anti-theft mode is input via the key input section.