JPH05183652A - Line terminal equipment - Google Patents

Abstract

(57) [Summary] [Purpose] To reliably protect the data communication control unit, etc. connected to the subsequent stage of the overvoltage protection unit and overcurrent protection unit from overvoltage. [Structure] An overcurrent protection unit 9 and an overvoltage protection unit 3 for preventing an abnormal current and an abnormal voltage generated in a telephone line 8 from being output to a subsequent stage are respectively provided. A data communication control unit 2 that controls the network of the telephone line 8 and controls transmission / reception of data is connected to a stage subsequent to the overvoltage protection unit 3 and the overcurrent protection unit 9. This means that the ground terminal is legally always grounded, and it is not necessary to install a protector.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line terminal device connected to a telephone line.

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional line terminal device 1 includes a data communication control unit 2 for controlling network and data transmission / reception of a telephone line 6, and a test voltage for the telephone line 6 connected to the telephone line 6. It is composed of an overvoltage protection unit 3 for absorbing an abnormally high voltage (for example, 250 V) or more. Also,
In this example, the overvoltage protection unit 3 is composed of a surge absorber, and the data communication control unit 2 is connected to an external water meter 4 which is a data communication device.

Next, the operation of the above configuration will be described.
Normally, the voltage of the telephone line 6 connected to the overvoltage protection unit 3 is 4
It is 8V, and the voltage generated on the telephone line 6 is AC 75 even when there is a call by the incoming signal from the telephone line 6.
It is about V (effective value). On the other hand, the maximum value of the DC voltage applied is 250 V which is the test voltage of the telephone line 6. That is, when the telephone line 6 is normal, at most 75V AC (212V peak voltage) or 250V DC
Only the voltage of is applied. On the other hand, the threshold voltage of the overvoltage protection unit 3 is set so that it does not operate when the voltage between the L1 and L2 of the telephone line 6 is normal, and the L1 and L2 are open. Therefore, telephone line 6 due to lightning, etc.
When an abnormally high voltage is generated between L1 and L2 and the ground, the surge absorber of the overvoltage protection unit 3 operates to release the abnormally high voltage to the ground via the earth terminal E. As a result, the telephone 5 and the data communication control unit 2 connected to the subsequent stage of the overvoltage protection unit 3 are protected from abnormal high voltage. The threshold voltage at which the overvoltage protection unit 3 operates is set to 250 V so that it does not operate when the telephone line is normal.
Although the above settings are made, the withstand voltage of the electric and electronic parts of the line terminal device 1 is set as low as possible in order to reduce the cost, and is set to, for example, 300 V which is a threshold voltage lower than that of a protector described later. ..

Next, the manner in which the line terminal device 1 is installed will be described with reference to FIG. In FIG. 4, the telephone line 8 is connected to the line terminal device 1 via the protector 7. The protector 7 is required to be installed according to the regulations for telecommunication facilities for business, and the purpose is to protect users and users from abnormal currents and voltages generated in the telephone line 8 due to lightning strikes and contact with strong current distribution lines. Do not give serious danger to home appliances and houses.

Further, according to the regulations for telecommunication facilities for business, the protector 7 is required to satisfy the following standards. 1) To be equipped with a surge absorber that operates at an alternating current of 500 V or less. 2) To have a fuse that operates at 7 A or less or a hot coil that operates at 500 mA or less.
The ground resistance should be 300Ω or less. FIG. 5 shows an example of the protector. The protector 7 in FIG. 5 is composed of an overvoltage protection unit 10 that operates under the conditions 1) and an overcurrent protection unit 9 that operates under the conditions 2). In the above configuration, when an abnormally high voltage is generated in the telephone line 6 due to lightning or the like, the overvoltage protection unit 10 operates to release the abnormally high voltage to the ground through the earth terminal E, and the discharge current generated at this time is for a long time. When it is exceeded, the fuse of the overcurrent protection unit 9 is blown to prevent the overcurrent from flowing to the line terminal device or the like connected in the subsequent stage.

[0006]

However, in the above-mentioned conventional configuration, the line terminal device 1 has the overvoltage protection unit 3 but does not have the overcurrent protection unit, and therefore has the following problems. 1) Since the protector 7 must be installed separately from the line terminal device 1, the installation work must be performed twice or in two places, and the work efficiency is not only deteriorated due to the extension of the installation work time. However, the labor cost was increasing due to the decrease in work efficiency. 2) Since grounding of the ground terminal E of the overvoltage protection unit 3 in the line terminal device 1 is not required by the regulations for telecommunication equipment for business, grounding work may not be actually carried out. Therefore, against the overvoltage generated between the telephone line 6 and the ground, an overvoltage occurs between the data communication device side such as the water meter 4 which may cause the overvoltage protection unit 3 not to operate and may be grounded. Sometimes it was connected.

[0007] The present invention solves the above-mentioned problems, and by having a security function stipulated in the regulations for telecommunication facilities for business, it is not necessary to separately install a protector, and labor costs are reduced by shortening the work time. It is an object of the present invention to provide a line terminal device that can reduce the number of devices and can surely protect a device or the like connected in a subsequent stage from lightning or the like by surely grounding a ground terminal.

[0008]

In order to achieve the above object, the line terminal device of the present invention has an overcurrent protection unit for preventing an abnormal current generated in a telephone line from being output to a subsequent stage, and a line terminal unit or a telephone line. An overvoltage protection unit that prevents the abnormal voltage generated between the telephone line and the ground from being output to the latter stage, and data that is connected to the latter stage of the overvoltage protection unit and the overcurrent protection unit to control the network of the telephone line and control the transmission and reception of data. A communication control unit is provided.

[0009]

According to the present invention, according to the above structure, when an abnormal current flows through the telephone line, the overcurrent protection unit prevents the abnormal current from flowing through the data communication control unit in the subsequent stage, and the abnormal voltage is supplied to the telephone line. In the case of occurrence, the overvoltage protection unit prevents the abnormally high voltage from being applied to the data communication control unit.

[0010]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2, 11 is a line terminal device, 8 is a telephone line, 4 is a water meter, and 5 is a telephone. The line terminal device 11 of the present invention is connected to the telephone line 8 and an overcurrent protection unit 9 for protecting a device connected to the latter stage from an abnormal current generated in the telephone line 8 and a telephone connected to the latter stage of the overcurrent protection unit 9 It is composed of an overvoltage protection unit 3 that protects a device connected in the subsequent stage from an abnormal voltage generated in the line 8, and a data communication control unit 2 that is connected in the subsequent stage of the overvoltage protection unit 3 and performs network control and data communication of the telephone line 8. Has been done. Further, in the present embodiment, a telephone 6 is connected to the latter stage of the overvoltage protection unit 3, and the water meter 4 is connected to the data communication control unit 2.
Are connected.

Further, in this embodiment, the overcurrent protection unit 9 and the overvoltage protection unit 3 satisfy the business telecommunication facility rules. That is, the overcurrent protection unit is composed of a fuse of 7 A or less, and the overvoltage protection unit 3 is 500 V AC.
It consists of a surge absorber that operates at the following voltage,
Further, the earth resistance of the surge absorber ground is 300Ω or less.

The maximum value of the voltage generated when the telephone line 8 is normal is 75 V AC at which the incoming signal arrives or 250 V DC which is the test voltage of the telephone line 8. The maximum value of the current flowing when the telephone line 8 is normal is 130 mA supplied by the exchange. In the above configuration, when the current and voltage of the telephone line 8 are normal, that is, when the current value is 130 mA or less and the voltage value is 75 V AC or less or 250 V DC or less, the overcurrent protection unit 9 and the overvoltage protection unit 3 are provided. Does not work. Telephone line 8
When an abnormal current flows through the fuse, the fuse of the overcurrent protection unit 9 is blown to prevent the overcurrent from flowing to the data communication control unit 2 and the telephone 6 in the subsequent stage. Further, when an abnormally high voltage is generated in the telephone line 8, the surge absorber of the overvoltage protection unit 3 operates, and an electric current is passed from the telephone line 8 to the ground to cause an abnormality in the data communication control unit 2 and the telephone 6 at the subsequent stage. Prevents high voltage from being applied.

Next, FIG. 2 is an installation configuration diagram of the line terminal device 11 of the present invention. The line terminal device 11 of the present invention is directly connected to the telephone line 8. Reference numeral 8 is a telephone line, 11 is a line terminal device of the present invention, 4 is a water meter, and 5 is a telephone.

As described above, since the line terminal device 11 of the present invention includes the overcurrent protection unit 9 and the overvoltage protection unit 3 and both satisfy the telecommunications equipment regulations for business use, the security that must be provided conventionally. There is no need to install a container, and the ground terminal is always grounded. That is, in the conventional installation work, the protector 7 and the line terminal device 1 had to be installed separately, which required a lot of trouble and time including the wiring work. Since it is only necessary to install only one installation work, the number of installation works can be reduced to one, work time can be shortened, work efficiency can be improved, and labor cost can be further reduced. Also,
Since the line terminal device 11 has the function of a protector stipulated in the regulations for telecommunication facilities for business, the ground terminal E is always grounded, and the data communication control unit 2 and the like grounded in the subsequent stage can be reliably protected from overvoltage. There is an effect.

By the way, the discharge start voltage of the overvoltage protection unit 3 should be set to a low voltage (for example, 300 V) which satisfies the standard of the telecommunications equipment regulation for business and does not hinder the normal line utilization voltage. The data communication control unit 2
It is possible to set the withstand voltage of the electric and electronic parts constituting the device to be low, and it is possible to provide a line terminal device with a cost advantage.

[0016]

As described above, the line terminal device of the present invention has both the overcurrent protection part and the overvoltage protection part, both of which satisfy the telecommunications terminal regulations for business use, and therefore must be provided conventionally. There is no need to install a protective device.
As a result, the number of installation works need only be one, so that the work time and work efficiency associated with the installation work can be shortened and the labor cost can be reduced. Also, since it has the role of a conventional protector, the ground terminal is always grounded, which has the effect of reliably protecting the data communication control unit connected to the subsequent stage of the through voltage protection unit and the overcurrent protection unit. ..

[Brief description of drawings]

FIG. 1 is a block diagram of a line terminal device according to an embodiment of the present invention.

FIG. 2 is a connection diagram when the device is attached.

FIG. 3 is a block diagram of a conventional line terminal device.

FIG. 4 is a connection diagram when the device is attached.

[Fig. 5] Internal configuration diagram of the protector based on the regulations for telecommunication facilities for business

[Explanation of symbols]

 2 Data communication control unit 3 Overvoltage protection unit 9 Overcurrent protection unit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takuo Shimada 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Masaaki Sakata, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Matsuda Akira 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Tadanori Shirasawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. An overcurrent protection unit that prevents an abnormal current generated in a telephone line from being output to a subsequent stage, and an abnormal voltage generated between the telephone lines or between the telephone line and the ground is output to a subsequent stage. A line terminal device comprising: an overvoltage protection unit for preventing; and a data communication control unit connected to the latter stage of the overvoltage protection unit and the overcurrent protection unit for performing network control of a telephone line and data transmission / reception control.