JPH073247U - Security device for wired communication equipment using commercial power supply - Google Patents

Abstract

(57) [Abstract] [Purpose] In order to protect wired communication equipment that uses a commercial power source, in addition to bypass protection between the commercial power supply line side and the communication line side, the grounding side of the communication device chassis ground line side also protects against ground Protecting against the intrusion of electric potential. [Structure] The security device comprises a power supply side security circuit section 1, a communication side security circuit section 2, and a chassis side security circuit section 3. The power supply side security circuit section 1 has a connection terminal section 5 to a commercial power line 23. The bypass lightning protection element 6, the resistance element 7, the varistor 8, the temperature fuse 9 and the like are included. The communication side security circuit section 2 includes a connection terminal section 10 to the communication line 22, a lightning protection element 11, and the chassis side security circuit. The portion 3 is composed of a series circuit of a connection terminal portion 12 between the signal ground of the communication device main body 21 and the frame ground of the chassis 26, a lightning arrester element 13, an inductance 14 and a resistor 15, and each lightning arrester element 6, 11,
They are connected via a common connection line 4 via 13.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a security device for OA equipment such as a computer connected to a communication line such as a telephone line and a commercial power supply line, a television camera, cable broadcasting, various emergency alarm devices, and communication devices such as an electronic key telephone.

[0002]

[Prior art]

 In control lines, cable broadcasting lines, telephone communication lines, etc. of various plants, outdoor communication lines are connected to various devices, and these various devices are usually connected to power lines such as commercial power sources. . For example, as shown in FIG. 2, a device main body 21 such as an emergency alarm device is connected to a communication line 22 and a commercial power line 23. In the above existing telephone communication line, a subscriber protector 24 is provided at the boundary between the outdoor line and the subscriber line, and a high voltage application is discharged to the ground by a lightning protection element to prevent harm to the human body and equipment. It was to protect the body. On the other hand, the majority of commercial power sources are of single-phase, three-wire type with neutral grounding, and generally have a structure in which one wire is grounded at a pole transformer. Further, an earth leakage breaker 25 and a breaker 27 are provided on the commercial power line. In addition, a lightning arrester for power supply has been proposed between the commercial power supply line and the ground in preparation for the intrusion of abnormal voltage such as lightning surge.

[0003]

[Problems to be solved by the device]

 Under the present circumstances, when an abnormal voltage such as a lightning surge enters from the communication line 22, for example, when the lightning arrester element of the subscriber protector 24 is discharged and discharged to the ground, the current and ground resistance cause the grounding. The potential of suddenly rises. Such a phenomenon is a local phenomenon near the ground point, and the potential of the ground point on the side of the commercial power supply away from it is low (Fig. 3). After that, it is applied to the communication line terminal and the power source side of the device body 21. When an abnormal voltage such as a lightning surge enters the commercial power supply line 23, the increase in the ground potential is applied to the device main body 21 via the ground / communication line in the same manner as above.

For this reason, the present inventor bypasses the abnormal voltage generated in the commercial power line 23 and the communication line 22 so that the increase in the ground potential due to the intrusion of the abnormal voltage such as lightning surge is not applied to the device body 21. In order to achieve this, a security device in which the power supply side security circuit section 1 and the communication side security circuit section 2 are connected by a common connecting line 4 has already been proposed (Shokaisho 62-178 749).

However, if the chassis 26 of the communication device is grounded also by this, when the abnormal voltage such as lightning surge enters the communication line 22 or the commercial power line 23, the ground line of the chassis 26 is disconnected. It is unavoidable that the ground potential is applied to the device body 21 after that. For example, a communication device of a special security company supplies a minute current to the ground side and uses a signal coming from the communication line 22, so that the chassis 26 needs to be grounded.

In view of the above-mentioned points, the present invention not only provides bypass protection between the commercial power line side and the communication line side, but also prevents the influence of abnormal voltage such as lightning surge from the ground line side of the communication device chassis. The purpose is to

[0007]

[Means for Solving the Problems]

 In order to solve the above problems, a protection device for a wired communication device using a commercial power source according to the present invention has a power supply side security circuit section connected to a commercial power supply line and a communication side security circuit section connected to a communication line. Connected with a common connection line, and further provided with a connection terminal that connects between the signal ground and frame ground of the wired communication device body, and a circuit with high resistance to surge voltage is connected between this connection terminal. At the same time, a chassis-side security circuit section to which a lightning protection element is connected is provided, and the chassis-side security circuit section is connected to the common connection line.

In a preferred embodiment, a circuit having high resistance to surge voltage is composed of a series circuit of an inductor and a resistance element.

[0009]

[Action]

 When an abnormal voltage such as a lightning surge enters from the communication line or commercial power line, the high voltage generated by this is bypassed to the power supply side security circuit section and the communication side security circuit section via the respective lightning protection elements. Further, the ground potential applied from the grounded communication equipment chassis side is bypassed to the power supply side security circuit section and the communication side security circuit section through the chassis side security circuit section.

[0010]

【Example】

 FIG. 1 is a circuit diagram of an embodiment of a security device for wired communication equipment using a commercial power line according to the present invention.

The security device for wired communication equipment includes a power supply side security circuit unit 1, a communication side security circuit unit 2, and a chassis side security circuit unit 3. The power supply side security circuit section 1 can be composed of a connection terminal section 5 to the commercial power supply line 23, a lightning protection element 6, a resistance element 7, a varistor 8 and a temperature fuse 9. The communication-side security circuit section 2 can be composed of a connection terminal section 10 to the communication line 22 and a lightning protection element 11.

Further, the chassis side security circuit section 3 is provided with connection terminal portions 12 and 12 between the signal ground of the device body 21 and the frame ground of the chassis 26, and the connection terminal portions 12 and 12 are provided with a lightning protection device. A circuit composed of 13, an inductance 14, and a resistance element 15 is connected, and the lightning protection element 13 is connected to the common connection line 4 via the lightning protection elements 6 and 11.

As the varistor 8, a non-linear element having a low impedance with respect to a high voltage is preferably used. As the resistance element 7, a non-linear element having a low initial resistance value, for example, a positive temperature coefficient thermistor is used. Further, the resistance element 15 can perform normal communication at a low frequency, and the inductance 14 is, for example, a choke coil having a high resistance against a surge voltage. It can also be used as an inductive resistance element having a resistance component and an inductance component. Further, as the lightning arresting elements 6, 11 and 13, there are cases where a gas arrester element, a vacuum arrester, a varistor or the like is used.

According to the above circuit configuration, when an abnormal voltage such as a lightning surge enters the communication line 22, the lightning arrester element of the protector 24 for the customer is discharged, and the voltage corresponding to the increase in the ground potential is transmitted to the communication side. It is applied to the security section 2 and bypassed from the common connection line 4 to the power line side via the lightning protection element 11.

When an abnormal voltage such as a lightning surge enters the commercial power supply line 23, the steep rising portion of the high voltage generated by the trowel is bypassed from the lightning protection device 6 of the power supply side security circuit unit 1 to the communication side. It The potential difference between the two commercial power supply lines 23 is absorbed by the parallel circuit of the resistance element 7 and the varistor 8 and the discharge of the lightning protection element 6, so that the fluctuation of the power supply voltage is also suppressed.

Further, when a voltage corresponding to the rise of the ground potential is applied to the communication device chassis side security circuit section 3 from the ground line, it is bypassed from the connection line 4 to the power line side or the communication line side via the lightning protection element 13. It In this way, the grounded three points on the communication line side, the commercial power line side, and the communication device chassis side are made to have substantially the same potential, so that the wired communication device main body 21 on the chassis 26 is protected from abnormal voltage such as lightning surge. Can be protected.

In addition, a series circuit of an inductance 14 and a resistor 15 is inserted between the connection terminal 12 and the device body 21 and the case 26, and the parallel connection of the lightning protection element 13 does not normally conduct current. A minute current of, for example, about 100 mA can be passed through the series circuit of the inductance and the resistance. Further, the series circuit of the inductance and the resistance has a high resistance against an abnormal voltage such as a lightning surge and prevents the lightning protection element 13 from entering the communication device main body 21 before being discharged.

The communication-side security circuit unit 2 has a plurality of circuits including a connection terminal unit 10 to the communication line 22 and a lightning protection element 11 for a plurality of wired communication devices 21 such as an electronic key telephone, a personal computer, and a facsimile. By providing them in parallel, it is possible to deal with each.

[0019]

[Effect of device]

 As described above, according to the present invention, when an abnormal voltage such as a lightning surge enters from a communication line or a commercial power line, the voltage corresponding to the rise of the ground potential is caused by the power side security circuit section and the communication side security circuit section. The voltage of the rise in ground potential applied from the ground side of the communication equipment chassis is bypassed from the chassis side security circuit section to the power supply side security circuit section and the communication side security circuit section. Since the three ground points on the line side, commercial power line side, and communication device chassis side are made to have approximately the same potential, this reliably protects the wired communication device body on the chassis from abnormal voltage such as lightning surge. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of a security device for a wired communication device using a commercial power source according to the present invention.

FIG. 2 is a circuit diagram of a conventional example of a security device for wired communication equipment that uses a commercial power source.

3 is an explanatory diagram of the ground potential at each ground point in FIG. 2. FIG.

[Explanation of symbols]

 1 Power supply side security circuit section 2 Communication side security circuit section 3 Chassis side security circuit section 4 Common connection line 5,10,12 Connection terminal section 6,11,13 Lightning protection element 8 Varistor 9 Temperature fuse 14 Inductance 7,15 Resistance Element 21 Wired communication device main body 22 Communication line 23 Commercial power line 26 Communication device chassis

Claims (2)

[Scope of utility model registration request] 1. A security device for wired communication equipment, which uses a commercial power supply line in which a power supply side security circuit section connected to a commercial power supply line and a communication side security circuit section connected to a communication line are connected by a common connection line. , A connection terminal portion for connecting between the signal ground of the wired communication device body and the frame ground is provided,
A chassis side security circuit section is provided in which a circuit having high resistance to surge voltage is connected between the connection terminal sections and a lightning protection element is connected, and the chassis side security circuit section is connected to the common connection line. A security device for a wired communication device using a commercial power supply, which is characterized in that: 2. A circuit having a high resistance to a surge voltage comprises a series circuit of an inductance and a resistance element.
Security device for wired communication equipment using the commercial power supply described.