JPH10210148A - Communication line switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a switching device that disconnects a subscriber's equipment and forms a continuity path for a measurement signal suitable for locating a fault location through the use of a remote control self-hold relay even on the occurrence of an earth fault or a fault contact. SOLUTION: When a negative pulse with a voltage in excess of a voltage of a constant voltage diode of a 1st changeover control circuit 1 is applied between a terminal L1 and an earth E as a 1st control signal, a relay RL1 is activated, which self-holds. A 1st continuity means 3 is connected, subscriber terminals T1, T2 are open and a 1st switching state is realized. The switching state is recovered by applying a normal operating voltage between terminals L1, L2. When a positive pulse with a voltage in excess a constant voltage of a constant voltage diode of a 2nd switching control circuit is applied between either of the terminals L1, L2 and the earth E as a 2nd control voltage, a relay RL2 is activated, which self-holds. A 2nd continuity means 6 is connected, the subscriber terminals T1, T2 are open and a 2nd switching state is realized. A 2nd return control circuit 5 is operated after a prescribed time and the 2nd switching state is recovered through the application of a normal operating voltage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used when a trouble occurs in a telephone line, a communication line, or an in-home device, for example, for maintenance work such as investigating a cause of the trouble.
The communication line separator of the present invention is always installed at the connection point (maintenance demarcation point) between the communication line and the home device, and is used when performing an isolation test by remote control from the installation location of the telephone exchange when an abnormal failure occurs. Is what is done.

[0002]

2. Description of the Related Art In general, a protector equipped with a lightning arrester and a fuse is provided at a drawing-in point of a communication line in a house. It is important to know which side has the cause. In the past, operators of telecommunications companies were dispatched to connect a measuring instrument etc. to the protector of the communication line with the abnormality, and to confirm whether there was an abnormality on the communication line side, but this method was used. In the method, even if there is an abnormality inside the house, a man-hour for the worker to be dispatched is required. Therefore, in recent years, a technique of separating a communication line at a maintenance demarcation point by remote control has been used.

[0005] FIG. 3 is a diagram showing a connection form from the exchange 11 to the home device 14 and a failure occurring on the communication line 12. The communication line is connected from the exchange 11 to the communication lines 12 (L1, L2) via the main wiring board 17, and further connected to the home device 14 via the maintenance demarcation point 10 of each subscriber's house. On the other hand, failures occurring in the communication line 12 include a disconnection failure 15a of the communication line, an insulation failure (interference failure) 15b between the pair of communication lines, and a ground failure 15c between the communication line and the ground. In order to cope with the case where the line failure or the failure of the home device 14 occurs, the communication line separator 1 is used.
3 is provided between the communication line 12 and the home device 14.

The communication line separator 13 switches the connection of the main wiring board 17 to a test device 18 when a failure occurs, disconnects the home device 14 by remote control, and uses the test device 18 to determine whether or not there is a failure in the communication line. The type and location of the obstacle was being measured.

FIG. 4 shows an example of the configuration of a communication line separator conventionally used for this purpose.

In this prior art, when a high voltage having a polarity opposite to that of the normal communication line is applied between the communication lines L1 and L2, the constant voltage diode ZD1 conducts, and the terminals L1 and R2 are turned on.
1, D1, ZD1, SCR1-G, SCR1-K, and the gate current of the thyristor SCR1 flow through the path of the terminal L2.
CR1 becomes conductive, and relay RL1 operates. In the figure, symbols such as RL1-1a indicate that they are the contacts of the first circuit of RL1, and a suffix a indicates that the contact is a normally closed circuit contact, b is a closed circuit contact during operation, and c is a common terminal. Is shown. Here, when the relay operates, the home device connected to the terminals T1 and T2 is disconnected by opening the normally closed circuit contact, and L1, RL1-1c, RL1-1b, and R1 are connected.
2. A signal conduction path is established by the path L2. SCR
1 holds the operation state while the current flowing through the SCR1 exceeds the minimum operation holding current. If the holding current is a value that can hold the relay in the operating state, the contacts maintain the separated state. To switch back the contacts, the SCR1 only needs to be returned to the non-operating state. Either eliminate the holding current flowing through the SCR1 or apply a normal voltage to apply a voltage of the opposite polarity to that at the time of separation. Apply.

[0007]

This conventional circuit is an excellent circuit that can perform isolation at a maintenance demarcation point by remote control and perform remote measurement. However, the signal between communication lines is used for isolation control. Therefore, if there is an insulation fault between communication lines (interference fault) or if one of the communication lines is broken, the in-home device cannot be disconnected. The conventional circuit requires a holding current to keep the switch circuit in the isolated state, and the conventional circuit requires the conduction path of the holding current to adapt to the measurement of the insulation fault position. If this is attempted, it is not possible to adapt in the event of a contact failure. In the measurement of insulation failure (ground failure) between the communication line and ground, sufficient accuracy is required to include nonlinear elements such as diodes in the conduction path. Can't get , There is a problem can not be applied because it is difficult to maintain a sufficient holding current during the measurement in the case of mild earthed fault.

The present invention realizes a separator capable of disconnecting an in-home device at a maintenance demarcation point by remote control even when a ground fault or a contact fault exists and a disconnection fault exists in one of communication lines. It is another object of the present invention to realize a separator which can form a conduction path of a measurement signal adapted to the measurement of the location of the fault together with the separation of the in-home device when a ground fault or a touch fault occurs.

[0009]

When there is an insulation failure such as a short circuit between communication lines, a signal between the communication lines cannot be separated and used for control. To solve this, a signal between the communication line and the ground line is used for disconnecting the home device. In this case, a conduction path for a measurement signal is formed between one of the communication lines and the ground line in order to disconnect the in-home device and enable the measurement of the fault location by remote measurement.

At the time of insulation failure between one of the communication lines and the ground, the communication line having the insulation failure and the ground line cannot be disconnected and used for control. In order to solve this, a signal between the communication line where the communication line has no trouble or the degree of the trouble is minor and the ground line is used for disconnecting the home device.
In this case, a conduction path for a measurement signal is formed between the communication lines in order to disconnect the in-home device and to enable the measurement of the fault location by remote measurement.

In order that the position of the insulation failure can be known with high accuracy by remote measurement, a non-linear element such as a diode is not included in the conduction path of the measurement signal.

A self-holding relay is used to eliminate the need for holding current for keeping the switch circuit operating.

When the communication line is restored, the voltage between the communication lines is used to return the in-home device from the disconnected state to the communicable state.

In a case where an insulation failure occurs between one of the communication lines and the ground, immediately after the switch is disconnected by the disconnection signal between the communication line and the ground line, the disconnection signal is used for the return. In order to prevent the voltage from being indistinguishable from the voltage between communication lines, a disconnection control is performed by a pulse current, and a circuit for providing a dead time immediately after the disconnection is provided.

[0015]

FIG. 1 is a diagram showing the configuration of an embodiment of the present invention.
The present invention will be described in detail with reference to FIG.

In FIG. 1, L1 and L2 are first and second line terminals to which communication lines are respectively connected, T1 and T2 are first and second home terminals to which home devices are respectively connected, and E is ground. This is a ground terminal connected to. RL1 and RL2 are well-known self-holding relays. In the drawing, symbols such as RL1-1a indicate that they are the contacts of the first switch of the relay RL1. The closed circuit contact during operation, c indicates a common terminal. The circuit state in the figure indicates a normal use state, that is, a return state after returning from the separated state. R1 and R2 are the first conducting means 3
And the second conduction means 6, which are the conduction paths of the measurement signal at the time of separation.

To operate the relay RL1, a first switch control signal having a negative polarity with respect to the ground terminal E is applied to the line terminal L1 by a control signal generator (not shown).
A series circuit of a relay RL1 and a first switching control circuit 1 is connected between the ground terminal E and the line terminal L1, and the first switching control circuit 1 becomes conductive at a voltage equal to or lower than a certain threshold value. Circuit.

That is, as the first switch control signal,
Voltage below a certain threshold value (for example, -65V), for example,-
When a pulse of 80 V is applied, the first switching control circuit 1 becomes conductive, and a positive current flows through RL1 to cause a change in R1.
L1 is set to the operating state. Thus, the switches RL1-1 and RL1-2 of RL1 are connected to the contact b.

The relay RL1 has a self-holding function, and maintains an operating state even after the control signal is stopped. At this time, an open circuit state is established between the communication line terminals L1 and L2 and the corresponding home terminals T1 and T2, that is, a first separated state is realized. At the same time, one side L1 of the communication line and the ground terminal E are connected via the first conduction means 3, and the first conduction path for the measurement signal is established.

To return the relay RL1, a normal operating voltage of the communication line is applied between the communication line terminals L1 and L2 via a communication line from a communication line voltage generator (not shown). When the applied voltage (the voltage of the line terminal L1 with respect to the line terminal L2) relative to the line terminal L2 is a normal operating voltage used for communication, for example, 48 V or higher, the first return control circuit 2 Is turned on, and RL1 is set to the return state by flowing a current of the opposite polarity to RL1. As a result, the communication line terminals L1 and L2 and the corresponding home terminals T1 and T2 are connected.

To operate the relay RL2, a second switch control signal having a positive polarity with respect to the ground terminal E is applied to the line terminal L1 or L2 by a control signal generator (not shown). That is, when a voltage higher than a certain threshold value, for example, a pulse of +80 V is applied as the second switch control signal, the second switching control circuit 4 is turned on, and a positive current flows through RL2 to put RL2 into an operating state. Set. Thereby, the switches RL2-1 and R
L2-2 is connected to the contact b side. Relay RL2 has a self-holding function, and maintains an operating state even after the control signal is stopped. At this time, the communication line terminals L1 and L2 and the corresponding home terminals T1 and T2 are in an open state,
That is, the second separation state is realized. At the same time, the second conduction means 6 is connected between the communication lines, and a second conduction path for the measurement signal is established.

In order to restore RL2, a normal operating voltage of the communication line is applied between the communication line terminals L1 and L2 via a communication line from a line voltage generator (not shown), similarly to the restoration of RL1. When the applied voltage is a normal operating voltage used for communication, for example, 48 V or higher, the second return control circuit 5 turns on the second return control circuit 5 and supplies a reverse-polarity current to RL2. To set RL2 to the return state.

The return suppressing circuit 7 prevents the RL2 switching control signal (second switch control signal) from being indistinguishable from the return control signal when an insulation failure occurs between one of the communication lines and the ground. For this reason, when the second switching control circuit 4 operates, the second return control circuit is controlled so as not to perform the return operation for a certain period of time.

FIG. 2 shows a specific example of a realizing circuit, and its schematic operation will be described.

The first switching control circuit 1 comprises a constant voltage diode ZD1, a diode D1, and a protection resistor R3.
When a first switch control signal exceeding the reverse breakdown voltage of ZD1 is applied between 1 and E, D1 and ZD1 become conductive, and a positive current flows through relay RL1 to cause R1.
L1 is set to the operating state.

The first return control circuit 2 comprises a diode D2 and a well-known constant current element J1 for overcurrent protection. When a communication line voltage is applied between L1 and L2, D1 is reset.
2 is in a conductive state, and a current of the opposite polarity is supplied to the relay RL1 to set the RL1 to a return state.

The first conducting means 3 is realized by a resistor R1,
When RL1 is set to the operating state, it becomes the first conduction path for the measurement signal.

The second switching control circuit 4 includes diodes D3 and D3.
4, D5, a constant voltage diode ZD2, and a protection resistor R4. When a second switch control signal exceeding the reverse breakdown voltage of ZD2 is applied between L1 or L2 and E, D3 or D4 and D5, ZD2 becomes conductive, and a current of positive polarity flows through relay RL2 to set RL2 to an operating state.

If there is a ground fault 15c on one side of the communication line, the second switch control signal is applied to the side where no fault has occurred. In this case, the signal becomes the reverse voltage of the diode D3 or D4 on the ground fault side, so that the ground fault 1
It can operate without being affected by 5c.

Even if there is a disconnection fault 15a on one side of the communication line, since the switch control signal flows via the diode D3 or D4, the operation can be performed even if there is a single disconnection fault.

The second return control circuit 5 includes a diode D8,
D9 and field effect transistors J2 and R5. J2 and R5 also function as a part of the return suppression circuit, but function as constant current elements similar to J1 in a steady state where no charge is stored in the capacitor C1. L
1, when the communication line voltage is applied between L2, D8,
D9 is turned on, and a current of the opposite polarity is applied to the relay RL2 to set the RL2 to the return state.

The return suppressing circuit 7 comprises a capacitor C1, diodes D6 and D7, and J2 and R5 which constitute a part of the return control circuit 5. When the second switch control signal is applied, a voltage appearing across the relay RL2 is accumulated in C1 through D6. After the second switch control signal is removed, the voltage accumulated in C1 through D7 is applied to the gate of J2, so that J2 is in a pinch-off state in which no current flows, and the second return control circuit 5 does not operate. become. The voltage stored in C1 is R5, D
7, C1 and RL2 gradually discharge, and after a certain period of time, the second switching control circuit 5 returns to an operable state again.

The second conducting means 6 is realized by a resistor R2,
When RL2 is set to the operating state, it becomes the second conduction path for the measurement signal.

In the above-described embodiment, a two-circuit, two-contact self-holding relay is connected in series to form a switch circuit for switching. In addition, a two-circuit, three-contact switch is also used as a switch circuit. A self-holding relay having a circuit configuration, for example, a rotary relay or the like can be applied. In this case, as the switch control signal, a control signal (combination of polarity, number of times of application, state, time, etc.) corresponding to the characteristics of each switch is selected.

In the above-described embodiment, the first and second conducting means are realized by using resistors. However, depending on the type of the measurement signal, other circuit elements such as an inductance, a capacitor, or a combination thereof may be used. Available.

[0036]

By using the communication line separator of the present invention, it is possible to cope with the following search and measurement of the cause of a failure. At the time of a touch fault, by switching to the first separation state, it is possible to identify which of the in-home device and the communication line has a fault,
If there is a touch fault in the communication line, remote measurement of the fault location by bridge measurement or the like becomes possible. At the time of disconnection failure, the home inside device is switched by switching to the second separation state,
It is possible to identify which of the communication lines has a failure, and if there is a disconnection failure in the communication line, it is possible to identify which or both of L1 and L2 are disconnected.

In the event of a ground fault, by switching to the second isolation state, it is possible to identify which of the home inside device and the communication line has a fault. If there is a single ground fault in the communication line, bridge measurement is performed. The remote location of the obstacle position can be measured.

As described above, even when there is a fault in a wider range, the in-home device can be disconnected, and not only can the fault type be reliably identified, but also remote control can be performed in the event of an insulation fault. As a result, it becomes possible to search for and locate the fault location, so that the measurement operation can be significantly reduced, and if there is a fault in the communication line, it can be quickly restored.

[Brief description of the drawings]

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

FIG. 2 is an example of an implementation circuit of the present invention.

FIG. 3 is an explanatory diagram of a usage form of a communication line separating device and a failure;

FIG. 4 is an explanatory diagram of a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st switching control circuit 2 1st restoration control circuit 3 1st conduction means 4 2nd switching control circuit 5 2nd restoration control circuit 6 2nd conduction means 7 restoration suppression circuit E Ground terminal L1, L2 Line terminal T1, T2 Home Terminal

Claims (7)

[Claims] A pair of line terminals to which a communication line is connected;
A pair of in-home terminals to which the in-home device is connected, a ground terminal connected to the ground, first conductive means for forming a conductive path for a measurement signal between one of the line terminals and the ground terminal, and a pair of line terminals A second conduction means for forming a conduction path for a measurement signal between the line terminal and the home terminal;
A switch circuit for switching connection to either one of said conducting means and said second conducting means, comprising: a first switch control applied between the communication line and ground; A switching control circuit that operates the switch circuit so as to select the first conduction unit or the second conduction unit according to a signal or a second switch control signal, respectively, wherein the line terminal and the home terminal are connected. A normal state, a first separated state in which the first conduction means is selected, and a second separated state.
A communication line separator which can switch between a second separation state in which a conduction unit is selected. 2. The switching control circuit according to claim 1, wherein the switching control circuit comprises a first switching control circuit and a second switching control circuit, and controls switching to a first separation state and a second separation state, respectively. Communication line separator as described. 3. The switch control circuit according to claim 2, wherein the second switching control circuit includes a circuit for providing a dead time during which the switch circuit is not switched back immediately after the switch circuit switches to the second disconnection state. Communication line separator as described. 4. The communication line separator according to claim 1, wherein the switch circuit comprises a two-circuit two-contact relay connected in series or a two-circuit three-contact relay. 5. The first switch control signal and the second switch control signal are signals that are distinguished by voltages having different polarities, or are signals that are distinguished by the number of times of application, state, and time of signal application. 2. The method according to claim 1, wherein
Communication line separator as described. 6. The communication line separator according to claim 1, further comprising a return control circuit for returning a switch circuit from the first disconnection state or the second disconnection state to a normal state. 7. The communication line separator according to claim 6, wherein the return control circuit operates when a normal operation voltage is applied between the communication lines.