JP2776763B2 - Anti-theft device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-theft device, and
The present invention relates to an anti-theft device for personal computer devices connected to a network such as an AN.

[0002]

2. Description of the Related Art Conventional personal computers were often used at home in the area of personal hobbies, so there was little need to worry about theft. Along with miniaturization, companies, schools, hospitals, and the like are increasingly using personal computers as terminal devices of large-scale LAN-connected networks, and there is a need to prevent theft of personal computers arranged in a distributed manner.

Conventionally, as means for preventing theft of personal computers and small electronic devices, for example, as shown in the electronic device of Japanese Utility Model Application Laid-Open No. 2-67416, a shaft or a key is attached to both corners of a personal computer substrate and a chain or key is attached and taken out. The most common method was to prevent FIG. 7A is a perspective view showing an example of conventional electronic device theft prevention. In addition, JitsuHiraku Akira 60-16
As shown in the product anti-theft device of Japanese Patent No. 4289, there is a device for preventing theft by sounding a buzzer or the like as anti-theft means. FIG. 7B is a circuit diagram illustrating an example of a product theft prevention unit.

[0004] Due to technological innovation, the performance of personal computer equipment has been improved,
As the size and weight have been reduced and the ease of use has increased, the number of companies that connect to a network and introduce a personal computer as a business processing terminal device has rapidly increased. Accordingly, demands for anti-theft measures are increasing, but it is difficult to eliminate theft damage by the conventional method. That is, in the related art, if a cutting tool is used, the chain is easily stolen, and a chain or a key can be seen by the eyes of a personal computer user, which impairs the aesthetic appearance of the office and causes discomfort.

[0005] Also, in the case of the input data and the discrepancy to register personal identification data it is also intended to stop the function of the equipment, but there is no substantial anti-theft effect. In addition, 60-1
No. 64289 forms a closed circuit using a wire or a micro switch for each product and terminal section, detects that the circuit is open when theft occurs, and sounds a buzzer to prevent theft. However, under the situation where most of the rooms in the building are unoccupied at night / holiday, etc., the effect of preventing theft by the buzzer cannot be expected.

Another problem is that it is not possible to immediately determine what device has been stolen, and it is not possible to centrally monitor theft of personal computer devices distributed throughout the building by LAN connection.

The present invention produces a siren sound at a place where a theft has occurred and gives psychological similarity to the other party, and has the effect of deterring a crime. Theft is detected in a theft monitoring device installed in a place (computer room or guard room) at the same time as the alto. An object of the present invention is to provide a system with an extremely high anti-theft effect capable of prompting a security guard or the like to the spot immediately by notifying a place and a stolen device to avoid theft damage.

The anti-theft device according to the present invention comprises a disconnection detecting circuit capable of detecting a signal level of a signal line connected to a device and judging disconnection or disconnection of the signal line, and a flip-flop for holding a state change of the disconnection detecting circuit. Circuit, a siren drive circuit that issues an alarm based on the output signal of the flip-flop circuit, and numerically converts the information of an address setting switch for notifying the place of the theft and the position information of the disconnection detection connector for identifying the stolen object. comprise constitute a display unit for displaying the address information obtained by analyzing the signal frequency on the main line to an external notification circuit for sending to the main line constituting the converted network to an AC signal by the push dial number transmitting circuit Te Is done.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention. Personal computer devices 1a to 1f for monitoring theft are connected to a personal computer antitheft device 2, and when a theft occurs, the location and theft device are determined. FIG. 2 comprising a personal computer theft monitoring device 4 capable of notifying information that can be transmitted through the main line 3 and displaying the information at a remote place.
PC device 1a. FIG. 4 is a connection diagram between the computer 1b and the personal computer anti-theft device 5, wherein a closed circuit is formed by using the loop signal line 5 or the microswitch 7; When a personal computer device is not connected to the connector terminal 8, a dummy connector 9 is inserted to form a closed-terminal circuit.

FIG. 3 is a block diagram of the personal computer anti-theft device 2. The disconnection detecting circuit 10 detects that the closed circuit has changed to the open state when the theft occurs, and the siren emits a siren sound at the site of the theft. A drive circuit 16,
An address setting circuit 12 for reporting the theft occurrence location information to the personal computer theft monitoring device 4 and two pieces of information on the connector locations 8a to 8b that have been detected for disconnection to know the stolen device are alternately switched and output by the selector circuit 22. After the numerical conversion by the ternary decoder 23, it is converted into an AC signal containing numerical information by the external notification circuit 13 and transmitted to the main line 3. The power supply circuit 16 is also provided with a charging circuit 17 so that theft can be monitored during a power failure.
And a battery 18.

FIG. 4 is a circuit diagram of the personal computer anti-theft device 2.

FIG. 5 is a block diagram of the personal computer theft monitoring device 4, which uses an empty telephone circuit in a building as a network trunk. By analyzing and displaying the AC signal including the numerical information transmitted through the trunk line 3, it is possible to know the stolen location and the stolen equipment.

In order to take out the personal computer 1, the loop signal line 5 in FIG. 1 must be cut or the connector 6 must be disconnected. The closed circuit of the personal computer device 1b is opened because the tape of the small micro switch is peeled off or the line is cut. 3. The connector terminals 8a to 8d of FIG.
Changes to the open state, the output of the OR circuit 10 changes to High level, and the flip-flop 11
Is set. As a result, the RL01 relay 15a is excited via the driver IC 14. Relay contact 15
b is in the make state, and the BZ01 siren 16 sounds. The flip-flop 11 switches the key switch 20 to the monitoring OFF position 20a for resetting the monitoring state during the relocation or maintenance work when the power supply 17 is turned on.
, And when the switch 20 is set to the reset position 20b to cancel the siren sounding state.

The information of the address setting switch 12 for notifying the location of the theft and the connector 8 that has been disconnected
The connector position information a to 8d is switched by time division in the selector circuit 22 and is used as an input signal of the decimal decoder circuit 23. For example, when a number is assigned to the device installation location and the address is set in the address setting switch 12, a 4-bit binary signal passes through a selector circuit 22 and a decimal decoder circuit 23.
Is set to At this time, the transmission circuit 3 of the theft monitoring device 4
6 (FIG. 6-E) is an AC cut filter 2
5. The signal is used as a select signal of the selector circuit 22 via the waveform shaping IC 26.

That is, when the select signal is at the High level, the "room number" information of the address setting switch 12 is changed to L level.
At the time of the ow level, the “stolen device” information of the disconnection detection position is alternately output at regular intervals. This information is set in the decimal decoder circuit 23 at the next stage, and a frequency signal corresponding to the “numeric value” is transmitted from the push-type dial number transmitting circuit 24 to the trunk line 3. If an AC signal is output from the own device while an AC signal is being output from the other personal computer theft prevention device 2 to the trunk line 3, the information may be disturbed. Therefore, the AC detection circuit 27 checks whether there is a "signal" output from another device. I do.

On the condition that no AC signal is output from another device, the output of the NAND gate 29 becomes low level by the disconnection detection signal a of the personal computer theft detection, and the flip-flop circuit 30 is set. The output signal of the flip-flop circuit 30 is a set permission signal of the decimal decoder circuit 23, and sets the output signal of the selector circuit 22 to the decimal decoder circuit 23. This state is maintained until the switch 20 reaches the reset position 20b.

On the other hand, the personal computer theft monitoring device 4 shown in FIG. 4 cuts the pulse signal for controlling the selector (FIG. 6-d) included in the signal on the trunk line 3 by the DC filter 31 and passes only the AC waveform, and performs frequency analysis. The frequency component is analyzed in the circuit 32. The obtained "numerical value" information is converted to 4-bit output by the dial number identification circuit 33, and the segment decoder 34 acts on the display section A39a and the display section B39.
b. An output signal of the transmission circuit 36 serving as a selector signal of the anti-theft device 2 is shared by the display permission signals of the display portions A39A and B39b.
a and the display section 39b are displayed alternately.

When the "0" side is selected by the input signal of the selector circuit 22 and the information of the address setting switch 12 is output, the value is displayed on the display section A39a. Conversely, when the "1" side is selected by the input signal of the selector circuit 22, the disconnection detection connector position information is displayed on the display section B39.
b. In this way, both the numerical values can be read by alternately displaying the data at 0.5-second intervals with perfect synchronization between the sending side and the receiving side. Further, the frequency analysis circuit 32 sounds the buzzer 35 while detecting the AC signal to notify the occurrence of the theft.

[0020]

As described above, the anti-theft device of the present invention emits a siren sound at a place where a personal computer device is installed, and at the same time, automatically reports the place of the theft and the stolen device to a burglar monitor installed at a remote place. You can rush to the site in a short time. This can be said to be a system that not only prevents attempted crimes but eliminates theft damage and also has a high antitheft effect. Further, according to the present invention, since an unused telephone line existing in the building is used as a trunk cable, no special cable construction is required and the introduction cost is low.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 2 is a connection diagram between the personal computer device of FIG. 1 and a personal computer anti-theft device.

FIG. 3 is an internal block diagram of the personal computer anti-theft device of FIG. 1;

FIG. 4 is a circuit diagram of the personal computer anti-theft device of FIG. 1;

FIG. 5 is a block diagram of a personal computer theft monitoring measure of FIG. 1;

FIG. 6 is a system operation time chart of the present invention.

FIGS. 7A and 7B are a perspective view and a circuit diagram showing an example of the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 (1a-1f) Personal computer equipment 2 Personal computer anti-theft device 3 Main line 4 Personal computer theft monitoring device 5 Lube signal line 6 Connector 7 Small micro switch 8 (8a-8d) connector terminal 9 Dummy connector 10,29 OR circuit 11,30 Flip-flop Circuit 12 address setting switch 13 external notification circuit 14 driver IC 15a relay 15b relay contact 16 sirenk drive circuit 17 power supply circuit 18 charging circuit 19 batteryoly 20a, 20b switch 21 AND 22 selector circuit 23 decimal decoder circuit 24 push-type dial number transmission Circuit 25 AC cut filter 26.28 Waveform shaping IC 27 AC detection circuit 31 DC filter 32 Frequency analysis circuit 33 Dial number identification circuit 34 Segment decoder 35 Buzzer 36 outgoing circuits 37 and 38 an inverter circuit 39a display portion A 39 b display unit B

Claims (3)

(57) [Claims] 1. A disconnection detecting circuit that senses a signal level of a signal line connected to a device and determines disconnection or disconnection of a signal line, a flip-flop circuit that holds a state change of the disconnection detecting circuit, and the flip-flop. A siren drive circuit that issues an alarm based on the output signal of the circuit, information on the address setting switch for reporting the location of the theft and information on the position of the disconnection detection connector for identifying the stolen object are numerically converted and the push-type dial number is transmitted. An external notification circuit that converts the signal into an AC signal by a circuit and sends the signal to a trunk constituting a network; and a display unit that displays address information obtained by analyzing a signal frequency on the trunk. And anti-theft device. 2. The anti-theft device according to claim 1, wherein a corresponding frequency signal is transmitted to a main line after being converted to a decimal value by a decimal decoder via a signal selector circuit at a disconnection detection point of the disconnection detection circuit. 3. The burglary monitoring device according to claim 3, wherein the stolen occurrence location information and the disconnection occurrence location information from the external notification circuit are alternately transmitted to the trunk line by synchronizing with the signal of the transmission circuit, and are similarly displayed alternately on the theft monitoring device side. 1. The anti-theft device according to 1.