JP2832196B2 - Telephone line disconnection detection device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone line disconnection detecting apparatus for detecting disconnection of a telephone line.

[Prior Art] Conventionally, there has been no device for detecting whether or not an abnormality (for example, disconnection) has occurred in a telephone line up to a subscriber telephone at a subscriber line exchange side of a telephone station.

[Problems to be Solved by the Invention] Therefore, when disconnection or disconnection of the telephone line or poor insulation occurs, the exchange cannot immediately recognize the abnormality of the telephone line. In addition, since the telephone line is inspected for abnormalities based on reports from subscribers, it takes a long time.

The present invention has been made in order to solve the above problems, and provides a telephone line disconnection detecting device that immediately detects a disconnection when a telephone line from an exchange to a subscriber telephone is disconnected by a blade. Aim.

[Means for Solving the Problems] and [Operation] To achieve the above object, the present invention provides a method for cutting a telephone line from a switchboard to a subscriber telephone by using a blade.
What is claimed is: 1. A telephone line disconnection detecting device for immediately detecting a disconnection, comprising: a voltage measuring unit for measuring a voltage value of a telephone line; and a current detecting unit for detecting an instantaneous current flowing when the telephone line is disconnected by a blade. Switching means for switching the telephone line to be measured to the voltage measuring means when an instantaneous current is detected by the current detecting means, wherein the telephone line to be measured is switched according to the measurement result by the voltage measuring means. It is characterized in that it is detected as a disconnection.

Further, in order to achieve the above object, the present invention relates to a telephone line disconnection detecting device for immediately detecting a disconnection when a telephone line from an exchange to a subscriber telephone is disconnected by a blade, and measuring the impedance of the telephone line. Impedance measuring means, a current detecting means for detecting an instantaneous current flowing when the telephone line is cut by a blade, and a telephone line to be measured when the instantaneous current is detected by the current detecting means. Switching means for switching to the impedance measuring means, wherein the measured telephone line is detected as a disconnection according to the measurement result by the impedance measuring means.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

<Description of Configuration (FIG. 1)> FIG. 1 is a diagram showing a telephone line state detecting device 1 according to the present embodiment.
FIG. 2 is a schematic block diagram showing the configuration of FIG.

As shown, the device 1 directly accommodates a subscriber,
In addition to the function of exchanging mutual calls, it is installed in the subscriber line exchange 2 having a function of supplying a call current to the telephone 3 and transmitting a ringing tone. ) Is a device for detecting whether or not the occurrence has occurred. The control unit 11 includes a control unit 11, a current detection unit 12, a switch 13, a relay 14, and a voltage measurement unit 15.

<Description of Operation (FIGS. 1 and 2)> The operation of the present apparatus 1 having the above configuration will be described below with reference to FIG. 1 and FIG.

First, the control unit 11 executes the operation of the apparatus 1 according to a processing procedure described later.
It comprises a CPU that controls the entire system, a ROM that stores processing procedures and control data of the CPU, and a RAM that includes a work area and various table areas used when the CPU executes processing. Then, the current value of the telephone line 16 detected by the current detection unit 12 is input.

A predetermined DC voltage (−48 V, 0 V) is supplied to the telephone line 16 from the above-described exchange 2.
When is off, the current value is "0", but when off, a current of several tens of mA flows continuously.

Here, when the telephone line 16 is cut by a blade or the like or the line 16 is short-circuited due to poor insulation, a current flows instantaneously. Therefore, the control unit 11 includes the current detection unit 12
As a result, when it is detected that a current has flowed for a very short time and then stopped, the relay 14 is driven as an abnormality of the telephone line 16. Then, the switch 13 is switched to the voltage measuring unit 15 side,
The voltage measuring unit 15 described later is started.

The switch 13 is switched to the current detecting unit 12 in the initial setting, and is switched to the current detecting unit 12 when the measurement by the voltage measuring unit 15 is completed.

Next, in the voltage measurement unit 15 started by the control unit 11, the capacitance between the two lines of the telephone line 16 and the electric charge stored in the internal capacitor of the telephone 3 are measured for several tens to several hundreds of milliseconds. Is measured, converted into a digital signal, and output to the control unit 11. Then, when the electric charge from the voltage measuring unit 15 is 21 or 22 shown in FIG. 2, the control unit 11 can determine that disconnection of the telephone line 16 or insulation failure has occurred. Second
In the figure, reference numeral 21 denotes a case where the cutting is performed by a blade or the like, and the voltage value becomes “0” in several tens msec. On the other hand, 22 is a case where one side is disconnected, and several hundred ms due to the capacitance of the telephone 3.
The voltage value becomes “0” at ec.

Accordingly, when a voltage value as shown in FIG. 2 is measured by the voltage measurement unit 15, the control unit 11 detects that the telephone line 16 has been disconnected or insulation failure has occurred. Then, the fact that cutting, insulation failure, or the like has occurred may be output to a display unit (not shown), or a buzzer or the like may be used.

It is also possible to report the occurrence of disconnection or insulation failure of the telephone line 16 to an external security company using an alarm device (not shown).

As described above, according to the present embodiment, when it is detected that an instantaneous current flows through the telephone line, by measuring the charge, it is possible to reliably detect the disconnection or disconnection of the telephone line. it can.

Another Embodiment Next, another embodiment according to the present invention will be described below with reference to FIG.

FIG. 3 is a block diagram showing a configuration of a telephone line state detecting device according to another embodiment.

The same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted. As shown in the figure, in this embodiment, the above-described voltage measuring unit 15 is an impedance measuring unit 15 ′ that measures the impedance (resistance value) of the telephone line 16, and the control unit 11 responds to the current value from the current detecting unit 12. The switch 13 is switched to detect an abnormality such as disconnection of the telephone line 15 or insulation failure based on the measurement result from the impedance measuring unit 15 '.

Therefore, according to this embodiment, disconnection or disconnection of the telephone line can be reliably detected as in the above-described embodiment.

Also, the present invention is not limited to the above-described embodiment,
Various modifications are possible. For example, instead of always detecting the current value, the current value may be detected at regular time intervals, and the voltage measuring unit 15 and the impedance measuring unit 15 'may be activated according to the current value.

In this case, it is needless to say that not only the case where the telephone line 16 is cut but also the case where only one side is cut with the ceramic scissors can be detected as an abnormality of the telephone line 16.

[Effects of the Invention] As described above, according to the present invention, when a telephone line from an exchange to a subscriber telephone is disconnected by a blade, an instantaneous current flowing through the telephone line is detected, and the disconnection is immediately performed. Can be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of a telephone line state detecting device according to this embodiment, FIG. 2 is a diagram showing voltage values at the time of disconnection or disconnection according to this embodiment, and FIG. 3 is a telephone line according to another embodiment. FIG. 3 is a block diagram illustrating a configuration of a state detection device. In the figure, 1 ... telephone line state detecting device, 2 ... exchange, 3 ... telephone, 11 ... control unit, 12 ... current detecting unit, 13 ... switch, 14 ... relay, 15 ... voltage measurement , 15 '... Impedance measuring section, 16... Telephone line.

Claims (2)

(57) [Claims] 1. A telephone line disconnection detecting device for immediately detecting a disconnection when a telephone line from an exchange to a subscriber telephone is disconnected by a blade, comprising: voltage measuring means for measuring a voltage value of a telephone line; Current detecting means for detecting an instantaneous current flowing when the telephone line is cut by a blade; and switching for switching a telephone line to be measured to the voltage measuring means when the instantaneous current is detected by the current detecting means. Means for detecting the telephone line under test as a disconnection in accordance with the result of measurement by the voltage measuring means. 2. A telephone line disconnection detecting device for immediately detecting a disconnection when a telephone line from an exchange to a subscriber telephone is disconnected by a blade, comprising: impedance measuring means for measuring an impedance of the telephone line; Current detecting means for detecting an instantaneous current flowing when a telephone line is cut by a blade, and switching means for switching a measured telephone line to the impedance measuring means when the current detecting means detects an instantaneous current. A telephone line disconnection detection device, comprising: detecting the measured telephone line as a disconnection in accordance with a result of measurement by the impedance measuring means.