JP2000339572A - Method for discriminating disconnection and short-circuit of regional acoustic wiring and device for detecting disconnection and short-circuit using the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method which can discriminate both disconnection and short-circuit of a regional acoustic wiring by applying the inverse voltage of the same value to the wiring. SOLUTION: A terminating unit T consisting of a resistance R is connected to an regional acoustic wiring L and one or more regional bells B to which the diodes D2 are connected are also connected in parallel to each other to the wiring L. Then the abnormal detection voltage having the direction opposite to the diodes D2 of the bells B is supplied to the wiring L and at the same time, the level of the current flowing to the wiring L is detected. Thus, a normal state, the disconnection or short-circuit of the wiring L is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of determining the disconnection and short circuit of a local acoustic wiring by applying a reverse voltage of the same type to the local acoustic wiring so as to determine the disconnection or short circuit of the local acoustic wiring. Method, and using the method,
The present invention relates to a disconnection / short circuit detection device for a district acoustic wiring, which can determine a disconnection or a short circuit in a district acoustic wiring.

[0002]

2. Description of the Related Art Conventionally, in a fire alarm system, when a fire detector installed in an appropriate place in a building issues an alarm, a fire receiver outputs a fire alarm and sounds a district bell corresponding to the fire detector. For this reason, the driving power is supplied to the district acoustic wiring connected to the district bell all at once.

The local acoustic wiring has a configuration as shown in FIG. 8, and a terminator T composed of a resistor R, a diode D3 and a zener diode Z connected in series is provided at the end of the local acoustic wiring L. In addition, the diodes D2 are connected in parallel with each other, and the district bells B connected to each other are connected in parallel. In addition, Bn and BC are district acoustic terminals, and the district acoustic wiring L is supplied with drive power from the fire receiver through these terminals Bn and BC, and when the district bell B is driven. Terminal Bn, terminal B
C is supplied with negative drive power.

In such a configuration, the local acoustic wiring L
Is determined as follows. That is, when the disconnection of the local acoustic wiring L is determined, a reverse voltage is supplied such that the terminal Bn is negative and the terminal BC is positive. The value is larger than the Zener voltage of the Zener diode Z. As a result, the terminal B
When a current flows between the C-terminal Bn, it is determined that the current is normal, and the terminal B
When no current flows between the C-terminal Bn, it is determined that the wire is broken.

On the other hand, when judging a short circuit in the local acoustic wiring L, a reverse voltage is supplied such that the terminal Bn is negative and the terminal BC is positive. The value does not flow, that is, a value smaller than the Zener voltage of the Zener diode Z. As a result, when a current does not flow between the terminal BC and the terminal Bn, it is determined that the current is normal, and when a current flows between the terminal BC and the terminal Bn, it is determined that a short circuit has occurred.

[0006]

However, in the above-mentioned conventional method, it is necessary to apply different values of reverse voltages to the local acoustic wiring when determining whether the local acoustic wiring is disconnected or short-circuited. In addition, two voltage supply circuits or voltage supply circuits for applying different levels of reverse voltages have been required.

The present invention has been made in consideration of the above circumstances, and determines both disconnection and short-circuit of a local acoustic wiring.
A disconnection / short circuit determination method for the local acoustic wiring which can be performed by applying a reverse voltage of the same value to the local acoustic wiring, and a disconnection or a short circuit of the local acoustic wiring can be determined using the method. It is an object of the present invention to provide an apparatus for detecting disconnection and short circuit of a local acoustic wiring.

[0008]

According to a first aspect of the present invention, there is provided a method for judging a disconnection or a short circuit of a local acoustic wiring, comprising the steps of connecting a terminator formed of a resistor and connecting a diode. A method for judging disconnection or short-circuit of a district acoustic wiring in which at least one or more district bells connected are connected in parallel, wherein an abnormal detection voltage is supplied to the district acoustic wiring in a direction opposite to a diode of the district bell. Then, the level of the voltage generated in the local acoustic wiring at that time is detected to determine normal, disconnection, and short circuit.

According to a second aspect of the present invention, there is provided a method for determining a disconnection or a short circuit of a district acoustic wiring, wherein a terminator constituted by a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel. Disconnection, short circuit determination method, in the district acoustic wiring, to supply an abnormality detection voltage in the opposite direction to the diode of the district bell, at that time to detect the level of the current flowing through the district acoustic wiring ,normal,
Disconnection and short circuit are determined.

According to a third aspect of the present invention, there is provided an apparatus for detecting disconnection and short circuit of a district acoustic wiring, wherein a terminator constituted by a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel. And, in this area acoustic wiring,
A switching control unit having a switching contact for switching between a driving power supply for supplying a driving voltage in a forward direction to the diode of the district bell, and an abnormality detection voltage having an inverted polarity with respect to the driving power supply; A control unit that, when an abnormal detection voltage is supplied to the local acoustic wiring, detects a level of a voltage generated in the local acoustic wiring at that time, and includes a signal processing unit that determines normal, disconnection, and short circuit. .

According to a fourth aspect of the present invention, there is provided an apparatus for detecting disconnection and short-circuit of a district acoustic wiring, wherein a terminator formed of a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel. And, in this area acoustic wiring,
A switching control unit having a switching contact for switching between a driving power supply for supplying a driving voltage in a forward direction to the diode of the district bell, and an abnormality detection voltage having an inverted polarity with respect to the driving power supply; A control unit that, when an abnormal detection voltage is supplied to the local acoustic wiring, detects a level of a current flowing through the local acoustic wiring at that time, and includes a signal processing unit that determines normal, disconnection, and short circuit. Disconnection and short-circuit detection device for regional acoustic wiring.

In the apparatus for detecting disconnection and short circuit of a local acoustic wiring according to a fifth aspect, the switching control unit includes a switching element that is driven at an appropriate cycle. An abnormal detection voltage is supplied to the acoustic wiring. In the method for judging disconnection or short circuit of a district acoustic wiring according to claim 6, a terminator constituted by connecting a diode in series to a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel. Disconnection and short circuit discrimination method of the established area acoustic wiring,
An abnormal detection voltage is supplied to the district acoustic wiring in the opposite direction to the diode of the district bell, and the level of the voltage generated in the district acoustic wiring at that time is detected to determine normality, disconnection, and short circuit. It is characterized by the following.

[0013] In the method for judging disconnection or short circuit of a local acoustic wiring according to claim 7, a terminator constituted by connecting a diode in series to a resistor is connected, and at least one or more local bells to which a diode is added are connected. This is a method for determining the disconnection and short circuit of the district acoustic wiring connected in parallel.
An abnormal detection voltage is supplied to the diode of the district bell in the opposite direction, and the level of the current flowing through the district acoustic wiring at that time is detected to determine normal, disconnection, and short circuit.

In the apparatus for detecting disconnection and short circuit of a district acoustic wiring according to claim 8, a terminator constituted by connecting a diode in series to a resistor is connected, and at least one district bell to which a diode is added is connected. A district acoustic wiring connected in parallel, a drive power supply for supplying a forward drive voltage to the district bell diode to the district acoustic wiring, and an abnormality detection voltage whose polarity is inverted with respect to the drive power supply, A switching control unit having a switching contact to supply switching, and by this switching control unit, when an abnormal detection voltage is supplied to the local acoustic wiring, the level of the voltage generated in the local acoustic wiring at that time is detected, A signal processing unit for determining normal, disconnection, and short circuit.

In the apparatus for detecting disconnection and short-circuit of a local acoustic wiring according to a ninth aspect, a terminator configured by connecting a diode in series to a resistor is connected, and at least one or more local bells to which a diode is added are connected. A district acoustic wiring connected in parallel, a drive power supply for supplying a forward drive voltage to the district bell diode to the district acoustic wiring, and an abnormality detection voltage whose polarity is inverted with respect to the drive power supply, A switching control unit having a switching contact to supply switching, and by the switching control unit, when an abnormal detection voltage is supplied to the local acoustic wiring, a level of a current flowing in the local acoustic wiring at that time is detected. And a signal processing unit for determining normal, disconnection, and short-circuit.

[0016] disconnection of the area acoustic wiring according to claim 10,
In the short-circuit detection device, the switching control unit includes a switching element driven at an appropriate cycle, and each time the switching element is driven, an abnormal detection voltage is supplied to the local acoustic wiring. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 detects the voltage,
An example of a method for determining disconnection and short-circuit of a local acoustic wiring according to the present invention which employs a method for determining the level, and an example of a disconnection and short-circuit detection device for a local acoustic device will be described.

The basic structure of the detecting device 1 will be described. As shown in the drawing, the detecting device 1 has a terminator T composed of a resistor R connected to the terminal and a diode D2 connected to each terminal. A district sound wiring L in which at least one or more district bells B are connected in parallel, a signal processing unit 10 for controlling the following units, and a direction opposite to the district acoustic wiring L with respect to the diode D2 of the district bell B. A voltage supply unit 11 for supplying an abnormality detection voltage, and when the abnormality detection voltage is supplied to the local acoustic line L by the voltage supply unit 11,
A voltage detector 12 for detecting a voltage Vi generated in the district acoustic wiring L, a driving power supply E for supplying a driving voltage in a forward direction to the diode D2 of the district bell B, and an abnormality detection voltage are transmitted to the district acoustic wiring L. Switching contacts SW1 and S for switching
And a switching control unit 13 having W2.

Here, in the normal standby state of the fire alarm system, the switching control unit 13 closes the switching contact SW1 to the b side and closes the switching contact SW2 to the a side. The switching contact SW1 is closed to the side a and the switching contact SW2 is closed to the side b, whereby the driving power E from the fire receiver is supplied to the local acoustic wiring L and the local bell B
Sounds all at once. PA and PB are voltage detectors 1
This is an input port provided in the signal processing unit 10 for inputting the comparison result from the second.

In such a configuration, the local acoustic wiring L
The basic operation of discriminating disconnection and short-circuit will be described. The signal processing unit 10 sends a signal from the voltage supply unit 11 to the local acoustic wiring L.
An abnormal detection voltage in the opposite direction is supplied to the diode D2 of the district bell B, that is, a power supply in which the terminal BC is positive and the terminal Bn is negative.

Then, a voltage Vi is generated in the local acoustic wiring L, and the voltage level at this time is detected by the voltage detector 12, and a predetermined threshold V for disconnection or short circuit is detected.
1, and V2 are compared with (V1> V2), and output to the signal processing unit 10 based on the result of the determination. Based on the result of this determination, the signal processing unit 10 disconnects, short-circuits,
Outputs a normal discrimination signal.

FIG. 2 shows a criterion for determination in the voltage detector 12. In this determination, the disconnection, short circuit, and impedance change in the normal state of the local acoustic wiring L are detected, and the impedance of the local acoustic wiring L is infinite in the case of a disconnection, almost zero in the case of a short circuit, and normal. In this case, the voltage corresponding to the terminator T is obtained, so that the voltage generated at the monitoring point A is set as the detection voltage Vi, and the detection voltage becomes Vi> V.
When it is 1, it is determined that a short circuit has occurred, when V2 <Vi <V1, it is determined that the circuit is normal, and when the detected voltage is Vi <V2, it is determined that a disconnection has occurred.

FIG. 3 shows a more specific configuration example of the detection device 1. In the detection device 1, the voltage supply unit 11 is configured by a switching element Tr and a photocoupler PC, and the voltage detection unit 12 is configured by two comparators using the threshold voltages V1 and V2 for short-circuit and disconnection as reference voltages. C1, C2
It consists of. The respective thresholds V1 and V2 are obtained by dividing the driving voltage E by the resistors R11 and R12 and R21 and R22, and are set so that V1> V2.
The voltage generated at the detection resistor RA is defined as a detection voltage Vi.

In the voltage supply section 11, the signal processing section 10 activates the photocoupler PC at an appropriate cycle, thereby activating the switching element Tr and supplying an abnormal detection voltage to the local acoustic wiring L. ing. When the abnormal detection voltage is supplied to the local acoustic wiring L, the voltage detection unit 12 compares the detection voltage Vi in the comparator C1 with a predetermined threshold V1, and the detection voltage Vi in the comparator C2.
Is compared with a predetermined threshold value V2, and the comparison result is output to the signal processing unit 10. Therefore,
The two comparators C1 and C2 detect that the detection voltage Vi is Vi> V
2, the input ports PA and PB of the signal processing unit 10
Are set to the L level, and the detection voltage Vi becomes Vi <V1
, The input ports PA and PB of the signal processing unit 10 are both set to the H level, and the detection voltage Vi is V2 <Vi <
In the case of V1, the input ports PA, P of the signal processing unit 10
Since B is at H and L levels, these input ports P
By determining the combination of the voltage levels of A and PB, it is possible to determine short-circuit, disconnection, and normality, and the results of these determinations are output to the display unit and sounding means.

Next, a method for detecting a disconnection / short-circuit of a local acoustic circuit according to the present invention employing a method of detecting a current and determining the level thereof, and a disconnection / short-circuit detecting device of the local acoustic apparatus will be described with reference to FIG. I do. In the detection device 1A, unlike the detection device 1 described above, a current detection circuit 14 is provided instead of the voltage detection circuit 12.

In this method, the signal processing unit 10 supplies an abnormal detection voltage from the voltage supply unit 11 to the local acoustic wiring L in the opposite direction to the diode D2 of the local bell B. That is, by supplying a voltage at which the terminal BC is positive and the terminal Bn is negative, a reverse voltage is applied to the local acoustic wiring L. At this time, the level of the detection current Ii flowing through the local acoustic wiring L is determined by the current detecting unit 14. The determination is made by comparing with predetermined threshold values I1 and I2, and the result of the determination is output to the signal processing unit 10.

FIG. 5 shows the criteria for determination in this case. The thresholds I1 and I2 (I1> I2) are set in advance to optimal values for determining whether the local acoustic wiring L is short-circuited or disconnected. And the result of the determination by the current detector 14 is Ii>
When I1, it is determined that a short circuit has occurred, when Ii <I2, it is determined that a disconnection has occurred, and when I2 <Ii <I1, it is determined that the connection is normal. This judgment criterion is based on the area acoustic wiring L
Is set based on the fact that a large current flows when the is short-circuited, no current flows when the wire is broken, and a current approximately equivalent to the terminator flows when the wire is normal. In the drawing, Rx indicates the equivalent impedance of the local acoustic wiring L provided in place of the terminator T, a value close to zero when a short circuit occurs, an infinity when disconnection occurs, and a value close to the terminator when normal. become.

FIG. 6 shows a more specific configuration example of the detection device 1A. The configuration will be described below together with the basic operation. In the detection device 1A, the voltage supply unit 11 includes a switching element Tr and a photocoupler PC, and the current detection unit 14 includes photocouplers PC1 and PC
2 and resistors R1 and R2. Here, as the resistance, a value satisfying R1> R2 is selected.

When the signal processing unit 10 drives the photocoupler PC of the voltage supply unit 11 at an appropriate cycle,
The switching element Tr is turned on, and the abnormality detection voltage is supplied to the local acoustic line L. This abnormality detection voltage is a diode (not shown) added to the district bell B of the district acoustic wiring L.
, The district bell B does not ring. , And the current detection unit 14
The two photocouplers PC1 and PC2 are directly connected, and the respective photocouplers PC1 and PC2 are provided with resistors R1 and R2 in parallel, and the photocouplers PC1 and PC2 are connected to each other by the voltage applied to the resistors R1 and R2. Are driven.

According to such a configuration, when the detection current Ii detected by the current detection unit 14 satisfies the condition of Ii> I1 when the abnormal detection voltage is applied to the local acoustic wiring L, the photocoupler PC1 , PC2 are both turned on. At this time, if the detection current Ii satisfies Ii <I2, the photocouplers PC1 and PC2 are both turned off. If the detection current Ii satisfies I2 <Ii <I1,
Photocoupler PC to which a resistor R1 having a large resistance value is connected
Since only 1 is turned on and PC2 is turned off, by inputting the on / off state of these photocouplers PC1 and PC2 to the input ports PA and PB of the signal processing unit 10,
In the signal processing unit 10, short circuit, disconnection, normality can be determined,
The results of these determinations can be output to a display unit or sounding means.

In the above-described method and detecting device, the terminator T is described as being composed of only the resistor R. However, as shown in FIG.
May be connected in series in the opposite direction to the diode D2 of the district bell B. The terminator having such a configuration is proposed in claims 6 to 10 in the claims, but the details thereof will not be described.

With this configuration of the terminator T, the diode D1 is provided in the direction opposite to the direction in which the current flows when the driving power is supplied to the local acoustic wiring L. Current does not flow through the terminator T
Current consumption can be eliminated.

[0033]

As will be understood from the above description, in the method for determining disconnection or short-circuit of the local acoustic wiring according to the first and second aspects of the present invention, the abnormal detection voltage is applied to the local acoustic wiring in the reverse direction of the diode. The normal, broken, and short-circuit of the district acoustic wiring is determined based on the level of the current flowing through the district acoustic wiring and the level of the voltage generated in the district acoustic wiring at that time. Can be determined by applying a reverse voltage of the same value to the local acoustic wiring. Therefore, unlike the related art, there is no need to provide a voltage supply circuit for supplying a reverse voltage having a different value for each of the disconnection determination and the short-circuit determination, which is particularly useful when constructing a system for monitoring with a control microcomputer. .

Further, since the terminator is composed of only a resistor, the terminator can be made non-polar. Claims 3 and 4
According to the apparatus for determining disconnection and short-circuit of the local acoustic wiring described in (1), the method for determining disconnection and short-circuit according to claims 1 and 2 can be realized.
In the apparatus for detecting disconnection and short circuit of the local acoustic wiring according to claim 5, when the method according to claim 1 or 2 is performed, the switching element is driven at an appropriate cycle without receiving a signal from the outside, As a result, the abnormal detection voltage is supplied to the local acoustic wiring, so that it is automatically
The disconnection and short circuit of the district acoustic wiring can be determined, and the district acoustic wiring can be constantly monitored and maintained in a highly reliable state.

In the method of determining disconnection or short circuit of the local acoustic wiring according to the sixth and seventh aspects, an abnormal detection voltage is supplied to the local acoustic wiring in the reverse direction of the diode to the local acoustic wiring, as in the first and second methods. Then, based on the level of the current flowing through the district acoustic wiring and the level of the voltage generated in the district acoustic wiring, the normal, broken, and short-circuit of the district acoustic wiring is determined. This can be achieved by applying a reverse voltage of the same value to the local acoustic wiring. Therefore, unlike the related art, it is not necessary to provide a voltage supply circuit for supplying a reverse voltage having a different value between the disconnection determination and the short-circuit determination. In addition, since a terminator is formed by connecting a diode to the resistor in series with the diode of the district bell in the opposite direction, when drive power is supplied to the district acoustic wiring, the terminator is connected to the terminator. Since no current flows, current consumption by the terminator can be eliminated.

In the apparatus for determining disconnection or short-circuit of the area acoustic wiring according to the eighth and ninth aspects, the disconnection according to the sixth and seventh aspects is provided.
A short circuit determination method can be realized. Further, in the apparatus for detecting disconnection and short circuit of the area acoustic wiring according to claim 10, claim 6 and claim 7.
In carrying out the method described in the above, the switching element is driven at an appropriate period even without receiving an external signal, thereby supplying an abnormal detection voltage to the local acoustic wiring. Thus, the disconnection and short circuit of the district acoustic wiring can be automatically determined, and the district acoustic wiring can always be maintained in a highly reliable state.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating the basic concept of a method of the present invention and a disconnection / short circuit detection device (for determining a voltage level of a local acoustic wiring) of a local acoustic device.

FIG. 2 is a diagram clarifying criteria for determining normality, disconnection, and short circuit based on threshold values V1 and V2.

FIG. 3 is a block diagram showing a specific example of a device of the present invention for determining a voltage level of a local acoustic wiring.

FIG. 4 is a diagram for explaining a basic concept of a method of the present invention and a disconnection / short circuit detection device (for determining a current level of a local acoustic wiring) of a local acoustic device.

FIG. 5 is a diagram illustrating criteria for determining normality, disconnection, and short circuit based on threshold values I1 and I2.

FIG. 6 is a block diagram showing a specific example of a device of the present invention for determining a current level of a local acoustic wiring.

FIG. 7 is a diagram showing another example of the terminator.

FIG. 8 is a diagram illustrating a conventional method for determining a disconnection or short circuit of a local acoustic wiring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Detection apparatus of disconnection and short circuit of district acoustic wiring 10 ... Signal processing unit 13 ... Switching control unit B ... District bell D1, D2 ... Diode L ... District acoustic wiring R ...・ Resistance Tr ・ ・ ・ Switching element SW1, SW2 ・ ・ ・ Switching contact

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5C087 AA32 AA43 BB06 CC05 CC06 DD04 EE03 FF01 FF04 FF12 GG31 GG36 GG55 5G405 AA04 AD06 BA01 CA12 CA23 CA58 DA02 DA05 DA11 DA15 EA28 EA43

Claims (10)

[Claims] 1. A method for judging disconnection or short-circuit of a local acoustic wiring in which a terminator composed of a resistor is connected, and at least one local bell to which a diode is added and connected is connected in parallel. Is characterized by supplying an abnormality detection voltage in the opposite direction to the diode of the district bell, detecting the level of the voltage generated in the district acoustic wiring at that time, and determining normal, disconnection, short circuit Disconnection and short-circuit detection method of the local acoustic wiring. 2. A method for judging disconnection or short circuit of a district acoustic wiring in which at least one or more district bells connected to a terminator constituted by a resistor and connected to a diode are connected in parallel. Supplies an abnormal detection voltage in the opposite direction to the diode of the district bell, detects the level of the current flowing in the district acoustic wiring at that time, and determines normal, disconnection, short circuit How to detect disconnection and short circuit in the area acoustic wiring. 3. A district acoustic wiring in which at least one or more district bells connected to a terminator constituted by a resistor and a diode are connected in parallel are connected to the district acoustic wiring. A switching power supply for supplying a forward driving voltage; a switching control unit having a switching contact for supplying an abnormality detection voltage having a polarity inverted to the driving power; A district which has a signal processing unit that detects a level of a voltage generated in the district acoustic wiring when an abnormality detection voltage is supplied to the wiring, and determines whether the voltage is normal, disconnected, or short-circuited. A disconnection and short circuit detection device for acoustic wiring. 4. A district acoustic wiring in which at least one district bell to which a terminator constituted by a resistor is connected and a diode is added and connected is connected in parallel; A switching power supply for supplying a forward driving voltage; a switching control unit having a switching contact for supplying an abnormality detection voltage having a polarity inverted to the driving power; A signal processing unit that detects a level of a current flowing through the area acoustic wiring when an abnormality detection voltage is supplied to the wiring, and determines whether the wiring is normal, disconnected, or short-circuited; A disconnection and short circuit detection device for acoustic wiring. 5. The switching control unit according to claim 3, wherein the switching control unit includes a switching element driven at an appropriate cycle, and each time the switching element is driven, A disconnection and short circuit detection device for the local acoustic wiring, which is configured to supply an abnormality detection voltage. 6. A method for judging disconnection or short circuit of a local acoustic wiring in which a terminator constituted by connecting a diode in series to a resistor is connected, and at least one or more local bells connected with a diode are connected in parallel. An abnormal detection voltage is supplied to the above-mentioned area acoustic wiring in the opposite direction to the diode of the area bell, and the level of the voltage generated in the area acoustic wiring at that time is detected, and the normal, open, and short circuits are detected. A method for detecting disconnection and short-circuiting of a local acoustic wiring, characterized in that: 7. A method for judging disconnection or short circuit of a local acoustic wiring in which a terminator constituted by connecting a diode in series to a resistor is connected, and at least one or more local bells connected to the diode are connected in parallel. An abnormal detection voltage is supplied to the above-mentioned district acoustic wiring in the opposite direction to the diode of the district bell. At that time, the level of the current flowing through the district acoustic wiring is detected, and the normal, disconnected, short-circuit is detected. A method for detecting disconnection and short-circuiting of a local acoustic wiring, characterized in that: 8. A district acoustic wiring in which a terminator constituted by connecting a diode in series to a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel; A switching control unit having a switching contact for switching between a driving power supply for supplying a driving voltage in a forward direction to the diode of the district bell and an abnormality detection voltage whose polarity is inverted with respect to the driving power supply; A control unit that, when an abnormal detection voltage is supplied to the local acoustic wiring, detects a magnitude level of a voltage generated in the local acoustic wiring at that time, and determines a normal state, a disconnection, and a short circuit. A disconnection and short-circuit detection device for acoustic wiring in a district. 9. A district acoustic wiring in which a terminator formed by connecting a diode in series to a resistor is connected, and at least one or more district bells connected with a diode are connected in parallel; A switching control unit having a switching contact for switching between a driving power supply for supplying a driving voltage in a forward direction to the diode of the district bell and an abnormality detection voltage whose polarity is inverted with respect to the driving power supply; A control unit that, when an abnormality detection voltage is supplied to the local acoustic wiring, detects a level of a current flowing through the local acoustic wiring at that time, and determines whether the current is normal, disconnected, or short-circuited. A disconnection and short-circuit detection device for acoustic wiring in a district. 10. The switching control unit according to claim 8 or 9, wherein the switching control unit includes a switching element driven at an appropriate cycle, and each time the switching element is driven, A disconnection and short circuit detection device for the local acoustic wiring, which is configured to supply an abnormality detection voltage.