JPS61288632A - Burglar proof circuit - Google Patents

Abstract

PURPOSE:To prevent talking at the occurrence of burglar by incrementing the count of a counter circuit by one when inputted unlock code is in error and stopping the reception of the unlock code when the count exceeds a predeter mined value. CONSTITUTION:A 3-digit unlock code entried in a register 3 is checked by an unlock code check circuit 4 of the next stage and when it is coincident, a release signal is outputted to an output terminal 8 by a lock release circuit 5. When the unlock codeis not coincident, the content of the circuit is incremented by one by outputting one pulse to the counter check circuit 7 and when it reaches a setting value, a signal interrupting a switching circuit 2 is outputted to prevent the key code from being inputted.

Description

[Detailed Description of the Invention] [Summary of the Invention] The present invention provides a method for checking whether the unlock code is correct each time an unlock code for unlocking the mobile telephone terminal is input into the unlock circuit of the mobile telephone terminal.

To provide an anti-theft circuit which increases the reliability of unlocking by checking whether an error is made and preventing input of an unlock code when an error is counted a predetermined number of times or more.

[Industrial application field]

The present invention relates to a theft prevention circuit for telephone terminals such as automobiles, particularly mobile telephones, and reduces the probability of unlocking without increasing the number of digits of the unlock code input to the unlock circuit. Regarding anti-theft circuit.

[Conventional technology]

Conventionally, with mobile telephone terminals, in order to prevent calls in the event that the telephone terminal was stolen, pressing the lock button would prevent calls, and the lock circuit would be activated by entering a predetermined unlock code. It is designed to be released. That is, if the unlock code is a predetermined code, the lock circuit is released and one call is possible. However, if the unlock code is not a predetermined code, the call cannot be made.

[Problem that the invention seeks to solve]

According to the conventional configuration described above, the number of digits of the unlock code is usually 3 or at most 4 digits.9For example, if the telephone terminal is stolen, If the thief entered all the combinations of three or four digits, the lock could be unlocked even if the person did not know the unlock code. For this reason, there is a drawback that calls can be made even with stolen telephone terminals.

[Means for solving problems]

The present invention has been made in view of the above drawbacks.

The purpose of this is to increase the count of the counter circuit by one if the input unlock code is incorrect, and to prevent the unlock code from being accepted when the counter circuit exceeds a predetermined value. The purpose is to prevent telephone calls in the event of theft, and the means for this purpose is to provide an unlocking device for the mobile telephone terminal.

An unlock code checking means for inputting an unlock code to release the lock.

Counting means for counting error outputs of the unlock code checking means.

This is achieved by a theft prevention circuit characterized in that when the counting means reaches a predetermined number of times, the input of the unlock code is cut off, thereby making it impossible to unlock the lock.

[For production]

In the present invention, in the above means, if the unlock code is checked by the unlock code checking means through the switching means and the unlock code is correct, it is possible to make a call through the unlock means. If not, the counter means increases the count by 1 each time the unlock code is input, and when the count reaches a predetermined number, the switch means is turned off via the counter check means. This operates to block the key code from being input to the lock release means.

〔Example〕

Two embodiments of the present invention will be described in detail below with reference to FIGS. 1 and 3.

FIG. 1 is a system diagram of the anti-theft circuit of the present invention.

FIG. 2 shows an example of a counter circuit.

FIG. 3 is a flow chart of the present invention.

In FIG. 1, for example, the unlock code.

The key code KC represented by 3 digits "256" is applied to the input terminal 1 and sent to the register 3 via the switching circuit 2.
is stored in The 3-digit unlock code entered in the register 3 is used by the unlock code check circuit 4 in the next stage to check whether the correct 3-digit key code represented by "256" has been input. The lock code value is compared with the input, and if it matches the unlock code, the lock release circuit 5 at the next stage outputs a signal for unlocking. Therefore, a lock release signal=5- is outputted to the output terminal 8, and it becomes possible to talk. If the key code inputted in the unlock code check circuit 4 does not match the Ajirok code, one pulse is output to the counter circuit 6 to increment the counter circuit 6 by one.

The counter circuit 6 consists of T-flip-flop circuits 6a, 6b, and 6c connected in series as shown in FIG. 2, and counts each time a pulse from the unlock code check circuit 4 is input to the T input of the first flip-flop circuit 6a. It will be possible. Outputs A, B, of such amplifier counter 6,
By adding C to the counter check circuit 7, the unlock code is a predetermined value set in advance.

In this embodiment, while the register 3 is counted up to "3", the key code input is allowed by resetting the register 3, but when the counter check circuit 7 reaches the predetermined default value of "4" check, the switching circuit 2 is reset. Configure the system so that the key code is not input by outputting a blocking signal.

FIG. 3 shows a flowchart of the present invention. When performing software processing using a computer, a release code ABC=256 is stored in advance in storage means such as RAM or ROM in the computer, and the release code ABC=256 is exchange between telephone terminals. First, after the start S, the third digit A is sent to the computer, and the sent third digit key code is compared within the computer to determine whether A=2. If YES here, the second digit B is sent to the computer and B=
A determination is made as to whether the number is 5 or not. Similarly, if YES here, the first digit C is sent to the computer to determine whether C=6 or not, and if YES, the lock release signal R
After being given ES, the lock is released and you can make calls. If A, B, and C are all 2.5°6, the counter is counted up and increases by 1 for each incorrect unlock code.

In this example, when the count value reaches "4", it is determined whether the count value is 4 or not, so if it is "4", the signal to cut off the switching circuit is If the count value that is output and blocks key code input is between 1 and 3, that is, the count value is not "4", the process returns to the starting position S and repeats the above-described flow.

〔Effect of the invention〕

The anti-theft circuit of the present invention is configured in two series.

Since the mobile telephone terminal is operated in such a way that even if the mobile telephone terminal is stolen, it is possible to prevent telephone calls from being made using the telephone terminal.

[Brief explanation of drawings]

Figure 1 is a system diagram of the theft prevention circuit of the present invention, and Figure 2 is the system diagram of the theft prevention circuit of the present invention.
Circuit diagram showing one embodiment of the counter circuit used in the figure, No. 3
The figure is a flowchart of the anti-theft circuit 1 of the present invention. 1... Input terminal 2... Switching circuit 3... Register 4... Unlock code check circuit 5... Lock release circuit 6... Counter circuit 7... Counter check circuit Fig. 2

Claims (1)

[Scope of Claims] An unlocking device for a mobile phone terminal includes unlocking code checking means for inputting an unlocking code for unlocking, and a count for counting error outputs of the unlocking code checking means. and a theft prevention circuit characterized in that when the counting means reaches a predetermined number of times, the input of the unlock code is cut off to prevent unlocking.