JP2660224B2 - Communication protector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used by connecting to a telephone subscriber line or other wired communication lines. The present invention is used at a connection point of a home line connecting a communication line and a telephone or other home device. The protector of the present invention protects a surge induced current caused by a lightning strike on a communication line or an abnormally high voltage or a large current caused by contact between a communication line and a power line from entering a home device, and protects a communication company (for example, NT
It is used to clarify the maintenance demarcation point between the communication line provided by T) and the home line provided by a user (for example, an NTT subscriber).

According to the present invention, a telecommunications company temporarily disconnects a connection between a communication line and a home line and temporarily short-circuits a pair of communication lines by using a remote control signal transmitted to the office line. Loop resistance of the communication line from the test stand and others,
The present invention relates to an improvement of a relay for disconnection and a communication protector including a disconnection control circuit for controlling the relay so that an insulation state or the like can be measured.

[0003]

2. Description of the Related Art FIG. 2 is a circuit diagram of a conventional device. This prior art device shows an example of a communication protector practically used for a communication line, and FIG. 2 is a circuit diagram of a main part thereof. This communication protector is used by inserting it into a connection point connecting the communication line and the home line, and has a remote disconnection function for separating the communication line and the home line together with the security function of the communication line. .

That is, in this apparatus, a central office terminal (L1, L2) to which a pair of local lines are connected, a ground terminal (E), and a home terminal (I1, I2) to which a pair of home lines are respectively connected. ), Said station terminal and ground terminal (E)
And a pair of fuses (F1, F2) connecting the central office terminal and the home extension terminal, respectively, as security functions. Further, the device has a pair of self-holding relay contacts (r1, r2) each having the potential of the central office terminal as a common contact and the potential of the home extension terminal as one contact, respectively. A relay winding (RL) for switching control;
A voltage exceeding a predetermined value (L1 = 0V, L2
= + ΑV) is applied, a detection circuit (DET) that detects this voltage and outputs a trigger voltage, and a detection circuit (DET) that is activated by this trigger voltage and becomes conductive to detect the voltage arriving between the office line terminals. Thyristor (SC) applied to the relay winding
R) and a voltage lower than the predetermined voltage (L1 =
0 V, L2 = + βV)
An apparatus provided with a disconnection control unit (U) including a diode (DT) for supplying a reverse voltage arriving between the local line terminals via the other contact of the relay contact to the relay winding. This prior art device has already been disclosed in Japanese Patent Application Laid-Open No. 3-229557.

The operation of the conventional apparatus shown in FIG. 2 will be briefly described. A pair of communication lines are connected to a central office terminal (L1, L2) from a telephone office via a cable. A home device typified by a telephone is connected to I2). In the steady state, the relay contacts (r1, r2) are in the home restoration terminals (I1, I2) when the relay is in the restored state, respectively.
Connected to the side. In the communication standby state (the telephone is on-hook), for example, L1 = 0V, L2 ≒ −48
V or L1 ≒ −48V, L2 = 0V, and the control circuit 3 does not operate at this voltage.
No current flows through. In the communication state (the telephone is in an off-hook state), the polarity of the DC voltage between the local line terminals (L1, L2) may be inverted, but since the absolute value of the voltage becomes smaller than in the standby state, the control circuit 3 operates. Therefore, no current flows through the separation control unit U.

When an abnormally high voltage is generated at the local line terminals (L1, L2), a discharge circuit (detailed circuit configuration is omitted) provided inside the security circuit (2) is short-circuited and the local line terminal (L) is short-circuited.
1, L2) to the ground terminal (E) to ground the high voltage. Further, when an abnormally large current is generated due to the contact of the power line, the fuses (F1, F2) are blown, and this is prevented from flowing into a home device or a local device.

When a disconnection operation is performed from the station side, a voltage (L) corresponding to a disconnection control signal is applied between the office line terminals (L1, L2).
1 = 0V, L2 = + αV) is applied for a short time. As a result, the control circuit 3 operates, and the thyristor (SCR) is turned on. Accordingly, a current flows through the relay winding (RL), and the relay contacts (r1, r2) are moved from the contact b to the contact a, respectively.
Switch to That is, the home extension terminals (I1, I2) are disconnected, and the local line terminal L2 → the fuse F2 → the relay contact r
A loop of 2 → loop circuit 1 → control circuit 3 → station line terminal L1 is configured.

At this time, a voltage can be applied to the local line terminal to perform an insulation test and a measurement of a loop resistance (loop test). This is called a cut-off test performed by disconnecting the home extension terminal.

[0009] When the disconnection test is completed, the voltage (L1 =
0V, L2 = -βV). This voltage forms a loop of the local line terminal L1, the fuse F1, the relay contact r1, the diode DT, the open side of the relay winding RL, the local line terminal L2, and the relay winding (RL) operates (recovery side). 2) Restore the relay contacts (r1, r2).

[0010]

This device has become useful and widely used. However, depending on the state of the line connecting the station side and the communication protector, the station line terminals (L1, L2) may be connected in the opposite way to the station side, in which case the polarity of the applied voltage is changed. It will be different, and the cut test as described above will not be possible at all. Even if there is such a reverse connection, general communication will not be affected in principle,
Even if you notice the opposite connection, you do not always need to repair the opposite connection immediately. Therefore, even if an attempt is made to perform a disconnection test on a line that has not been restored, the disconnection test becomes impossible.

Although very rare for a self-holding relay contact used in this device, a phenomenon that the contact stays at a neutral position may occur. In this method, a voltage corresponding to the disconnection control signal is applied between the local line terminals (L1 and L2) for a short time in order to perform the disconnection test. At this time, the relay contacts r1 and / or r2 are separated from the contact b side. Moreover, this is a phenomenon in which the robot stays at the neutral position before contacting the contact a. In the worst case where this phenomenon occurs, only the relay contact r1 remains at the neutral position and the relay contact r2 is in contact with the contact a. In this state, even if an attempt is made to restore the relay contacts (r1, r2) by applying a voltage corresponding to the return control signal to the local line terminal to restore the relay contact (r1, r2), the diode (DT) does not become conductive, so that the relay winding ( RL) cannot flow a current having an open side polarity. Even if a voltage corresponding to the disconnection control signal is applied to the local line terminals (L1, L2) again, the local line terminal L2
→ Fuse F2 → a side of relay contact r2 → Loop circuit 1
Since the control circuit 3 → the station line terminal L1 forms a loop, the cutoff control voltage detection circuit (DET) does not output a trigger voltage, and thus the thyristor (SCR) does not operate. Therefore, no current can flow to the energized side of the relay winding (RL) again. Although very rare,
In such a worst case, no remote control can be performed on either side of the separation control and the separation control.

The present invention has been made in such a situation, and the local line terminals (L1, L2) depend on the state of the line.
Even if the relay is connected in reverse to the station, or if the relay contact of the relay being used remains in the neutral position, the disconnection test and the line communication An object of the present invention is to provide a communication protector that can perform restoration.

[0013]

According to the present invention, a full-wave rectifier (REC) is inserted between the disconnection control unit (U) and the local line terminals (L1, L2) so that the polarity of the local line is changed. The disconnection control unit is configured to operate even in the case of reverse rotation, and the relay winding driving the relay contacts (r1, r2) is connected to the first relay winding (RL1) for disconnection control and the recovery winding for recovery control. And the second relay winding (RL2) for the recovery control, a pair of relay contacts (r1,
r2) is characterized in that even if one of them becomes neutral, a current for recovery control flows from the other.

That is, according to the present invention, a local line terminal (L1, L2) to which a pair of local lines are respectively connected, and a ground terminal (E)
And a home extension terminal (I
, I2), a security circuit (2) connected between the central office terminal and the ground terminal, and a pair of fuses (F1, F2) respectively connecting the central office terminal and the home extension terminal.
2) and a pair of relay contacts (r1, r2) each having the potential of the office line terminal as a common contact and the potential of the home extension terminal as one contact, respectively, and controlling switching of the relay contacts. And a voltage exceeding a predetermined value (L1 = 0V, L2 = + α) is applied to the relay winding (RL1) and the local line terminal.
And a detection circuit (DET) that detects this voltage when V) is applied and outputs a trigger voltage, and a voltage that is activated by the trigger voltage and becomes conductive so that the voltage arriving between the office line terminals is equal to the first voltage. Thyristor (SC)
R), the communication protector provided with a disconnection control unit (U) including the disconnection control unit (U) and the station line terminal (L1, L1).
L2), a full-wave rectifier (REC) is inserted in the connection circuit, and a second relay winding (RL2) for restoring and controlling the relay contacts (r1, r2) and the first relay winding (R
L1) when there is a current, this second relay winding (R
Circuit means (PH1, PH2) for blocking the current of L2), and applying a voltage (L1 = 0V, l2 = + βV) lower than the predetermined voltage arriving between the local line terminals to the relay contacts (r1, r2). A rectifier circuit (DT) is connected to a path for supplying the second relay winding (RL2) via the other contact (a) of the rectifier circuit (DT2).
, DT2), the lower voltage (L1 = 0V, L2
= + ΒV) is connected.

The circuit means for blocking the current in the second relay winding (RL2) when there is a current in the first relay winding (RL1) includes photocouplers (PH1, PH2), and the light emitting element of the photocoupler. (PH1) is connected in series with the first relay winding (RL1), and the light receiving element (PH2) of this photocoupler is a normally-off type and is connected in parallel with the second relay winding (RL2). It is desirable to have a configuration.

[0016]

Since a full-wave rectifier (REC) is provided between the disconnection control unit (U) and the local line terminals (L1, L2), even if the polarity of the local line is reversed, it is disconnected. The minute control operates normally.

Further, the pair of relay contacts (r1, r
2) A first relay winding (RL1) for driving to the separation side (a side) and a second relay winding (RL2) for driving this to the recovery side (b side) are separately provided. . A path for applying a voltage to the first relay winding (RL1) for controlling the separation of the relay contacts (r1, r2) and a voltage for applying the voltage to the second relay winding (RL2) for controlling the relay contact recovery. Rectifier circuits (DT1, DT2) in both paths
Is provided, the current of a constant polarity is always supplied to the separation control unit (U) regardless of the polarity of the voltage arriving at the local line terminals (L1, L2).

However, with this configuration, current flows simultaneously in the first relay winding (RL1) and the second relay winding (RL2), and both relay windings operate. Therefore, the first relay winding (RL
1) is given priority when there is current, and when there is current in the first relay winding (RL1), the second relay winding (R
L2) was provided with circuit means for preventing current from flowing. Specifically, this circuit means was simply realized by a photocoupler. This circuit means can be realized by another relay circuit or semiconductor relay without using a photocoupler.

In the photocoupler circuit, a light emitting element of a photocoupler that emits light when a current is present in the first relay winding (RL1) is provided, and a light receiving element of the photocoupler that is paired with the light emitting element of the photocoupler is a second light emitting element. Relay winding (RL
2) If the light receiving element of the photocoupler is normally off, it is inserted in parallel if it is normally on, and if it is normally on, it is inserted in series. If there is current in the first relay winding (RL1), it is connected in parallel to the second relay winding. It is configured to bypass the current to flow and block if it is in series. In this way, simultaneous operation of the two relay windings is prevented.

According to the structure of the present invention, even if one of the relay contacts becomes neutral, the polarity of the current for recovery is reversed so that the second relay for recovery control is restored from the other relay contact. Since current can be sent to the relay winding, there is no phenomenon that remote operation cannot be performed while the relay contact is in a neutral state.

In the apparatus according to the present invention, since a full-wave rectifier (REC) is provided between the disconnection control unit (U) and the local line terminals (L1, L2), the operation may be interrupted due to some trouble occurring in the scale. Even if it becomes impossible, the polarity can be reversed and the separation control can be restarted from the beginning, so that the relay contacts (r1, r2) can be controlled to the switching side (a) again. Therefore, for this reason as well, the likelihood of occurrence of inconvenience that remote operation becomes impossible is further reduced. Therefore, in the device of the present invention, the pair of relay contacts (r1, r2) can be configured as an interlocking type.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a configuration diagram of an apparatus according to an embodiment of the present invention.

The apparatus according to the embodiment of the present invention comprises a local terminal L1 and a local line L2 to which a pair of local lines are respectively connected, and a ground terminal E.
And a home extension terminal I1 to which a pair of home extensions are respectively connected.
And I2, a security circuit 2 connected between the local line terminals L1 and L2 and the ground terminal E, and a pair of fuses F1 and F2 connecting the local line terminals L1 and L2 and the home terminal I1 and I2, respectively. F2, and relay contacts r1 and r2 each having the potential of the local line terminals L1 and L2 as a common contact and the potential of the home extension terminals I1 and I2 as one contact, respectively.
When the voltages L1 = 0V and L2 = + αV exceeding predetermined values are applied to the first relay winding RL1 for controlling the separation of the second line and the local line terminals L1 and L2, the trigger voltage is detected by detecting these voltages. A detection circuit DET to be output, and a thyristor S that is activated by the trigger voltage and becomes conductive to apply a voltage arriving at the local line terminals L1 and L2 to the relay winding RL1.
CR, which is connected between the local line terminals L1 and L2 via the other contact r1 or r2 of the relay contacts r1 and r2, and the voltages L1 = 0V and L2 = lower than the predetermined voltage
In a communication protector provided with a separation control unit U including a Zener diode ZD conducting at + βV, a full-wave rectifier REC is inserted into a connection circuit between the separation control unit U and the local line terminals L1 and L2, A second relay winding RL2 for restoring and controlling the relay contacts r1 and r2, and a second relay winding R when there is current in the first relay winding RL1.
A light emitting element PH1 of a photocoupler connected in series with a first relay winding and a light receiving element PH2 of a normally-off photocoupler connected in parallel with a second relay winding RL2, which are circuit means for avoiding the current of L2. And the second relay windings L1 = 0V and L2 = + βV, which are lower than the predetermined voltage, coming between the local line terminals L1 and L2 via the other of the relay contacts r1 and r2. Zener diode ZD
Is connected, and the other contact r of the relay contacts r1 and r2
A second relay winding RL2 is connected to a connection point between 1 or r2 and the diodes DT1 and DT2.

Next, the operation of the apparatus according to the embodiment of the present invention will be described with reference to FIG. The voltages applied from the station side are voltages L1 = 0 V and L2 = −48 V during on-hook standby, and voltages L1 = 0 V and L2 = −4 during off-hook communication.
8V or L1 = -48V, L2 = 0V (this voltage value is the maximum value).

When performing a remote disconnection operation for a disconnection test, first, the on-hook state of the terminal is checked. When the on-hook state of the terminal is confirmed, voltages L1 = 0V and L2 = + αV (α> 48) corresponding to the disconnection control signal are applied. The voltages L1 = 0V and L1 = + αV are applied to the rectifier REC of the disconnection control unit U as shown in FIG. At this time, the voltage is L1 = + αV and L depending on the state of the line.
Even if 2 = 0 V, the output side becomes normal polarity by the rectifier REC. When an output voltage + αV from the + side of the rectifier REC is applied, the control circuit 3 operates.
That is, the detection circuit DET detects this voltage + αV and outputs a trigger voltage, and the thyristor SCR is activated by this trigger voltage and becomes conductive.

Thus, the local line terminal L2 → rectifier R
EC (+ side) → first relay winding RL1 → photocoupler light emitting element PH1 → thyristor SCR → rectifier REC1
(− Side) → A loop of the local line terminal L1 is formed, a current flows, and the first relay winding RL1 is energized.

The light emitting element PH1 of the photocoupler inserted in the middle of this loop operates together with the energization of the first relay winding RL1, and the light emitting element PH1 emits light. In response to this, the light receiving element PH2 of the photocoupler also operates, becomes active, and becomes conductive. Here, the light receiving element PH2 of the photocoupler is normally off.

With the energization of the first relay winding RL1, the relay contacts r1 and r2 switch from the contact b to the contact a. Voltages L1 = 0V and L2 corresponding to cut control signals
= + ΑV is applied for a short time, but is still applied when the relay contacts r1 and r2 are switched from the contact b to the contact a. This voltage L1 = 0V and L2 = + αV
Is the line terminal L2 → fuse F2 → relay contact r2 → diode DT2 → branch point A → photocoupler light receiving element PH
2 → a rectifier REC (− side) → a loop of the local line terminal L1 and a current flows through this loop, so that the first relay winding RL1, the thyristor SCR, the light emitting element P of the photocoupler
H1 is restored. Using this loop, the loop resistance is measured (loop test) with the voltages L1 = 0V and L2 = + αV. If this is the case, the light receiving element PH of the photocoupler
2 is not in the active state (conduction), the voltage L1 = 0V and L2 = + αV are applied to the local line terminal L2 → fuse F2 → relay contact r2 → diode DT2 → branch point A → Zener diode ZD → second relay winding RL2 → rectifier REC
(− Side) → A loop of the local line terminal L1 is formed, but since the second relay winding RL2 operates to move the relay contacts r1 and r2 to the recovery side, the first relay winding RL1 and the second relay winding RL2 Both of the relay windings RL2 operate, and the relay contacts r1 and r2 perform abnormal operations such as chattering. The light receiving element PH2 of the photocoupler has a function of avoiding such a state. At this time, depending on the state of the line, the applied voltage is L1 = + αV and L2.
Even if = 0V, the output side has a normal polarity by the rectifier REC and the diodes DT1 and DT2.

Thus, the relay contacts r1 and r2
Is switched to the contact a side, the relay contacts r1 and r2 remain self-holding even if the energized state of the first relay winding RL1 is released. In this state, an insulation test can be performed.

Next, the voltages L1 = 0V and L2 = + βV
When (β <α) is applied, the local line terminal L2 → the fuse F2
→ Relay contact r2 → Diode DT2 → Zener diode ZD → Relay winding RL2 → Rectifier REC (-side) →
A loop of the office terminal L1 is formed. Specific values of α and β are individually set to values that do not affect equipment according to the line standard used, the type of exchange connected, the type and standard of home equipment, and the like. You.

At this time, even if the applied voltage becomes L1 = + βV and L2 = 0V depending on the state of the line, the local line terminal L1 → the fuse F1 → the relay contact r1 → the diode DT1 → the branch point A → the Zener diode ZD → The relay winding RL2 is energized by a loop configuration of the relay winding RL2 → the rectifier REC (− side) → the local line terminal L2, and the relay contact r
1 and r2 are restored.

[0032]

According to the present invention as described above,
Even when the office side and the office line terminal are connected in reverse depending on the state of the line, the disconnection test can be performed by remote control.
In addition, even if a phenomenon occurs in which the relay contact stays at the neutral position, the current can be supplied from another circuit to either the recovery control or switching control relay winding by reversing the polarity. Therefore, the inconvenience that remote control becomes impossible and switching back cannot be performed does not occur.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of an apparatus according to an embodiment of the present invention.

FIG. 2 is a circuit configuration diagram of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Loop circuit 2 Security circuit 3 Control circuit DET detection circuit DT, DT1, DT2 Diode E Ground terminal F1, F2 Fuse I1, I2 Home terminal L1, L2 Local terminal PH1 Light emitting element PH2 Light receiving element REC Rectifier RL Relay winding RL1 First relay winding RL2 Second relay winding r1, r2 Relay contact SCR thyristor U Cutoff controller ZD Zener diode

Claims (2)

(57) [Claims] 1. A central office terminal (L1, L2) to which a pair of local lines are connected, a ground terminal (E), and a home terminal (I1, I2) to which a pair of home lines are connected, respectively. A security circuit (2) connected between the central office terminal and the ground terminal, a pair of fuses (F1, F2) for connecting the central office terminal and the home extension terminal, respectively, And a pair of relay contacts (r1,
r2), and a first relay winding (R
L1) and a voltage exceeding a predetermined value (L1 =
0V, L2 = + αV), a detection circuit (DET) that detects this voltage and outputs a trigger voltage, and a voltage that is activated by this trigger voltage and becomes conductive so that the voltage arrives between the office line terminals. And a thyristor (SCR) for providing the first relay winding with a disconnection control unit (U), wherein the disconnection control unit (U) and the local line terminals (L1, L2) ), A second relay winding (RL2) for restoring and controlling the relay contacts (r1, r2) and the first relay winding (RL).
1) When there is a current in this second relay winding (RL)
Circuit means (PH1, PH2) for blocking the current of 2), and applying a voltage (L1 = 0V, L2 = + βV) lower than the predetermined voltage arriving between the local line terminals to the relay contact (r
Rectifier circuit (DT1, r1, r2) through the other contact (a) to the second relay winding (RL2).
DT2), the low voltage (L1 = 0V, L2 = +
A communication protector, wherein a Zener diode (ZD) that conducts at βV) is connected. 2. The circuit means for blocking the current in the second relay winding (RL2) when a current is present in the first relay winding (RL1) includes a photocoupler (PH1, PH2). The light emitting element (PH1) is connected in series with the first relay winding (RL1), and the light receiving element (PH2) of this photocoupler is a normally-off type and is connected in parallel with the second relay winding (RL2). The communication protector according to claim 1, wherein: