JPH09224095A - Data communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prolong the service life of a battery and to perform sure meter reading by discriminating whether or not the OFF of an AC power supply is due to a power failure and continuing or stopping the meter reading of a meter. SOLUTION: When the AC power supply of a terminal equipment 8 is turned OFF, an auxiliary power supply is switched to and a command for requesting the continuation of the meter reading is transmitted from a sub-center 3 to the terminal equipment 8 within the fixed time. When the terminal equipment 8 does not receive the command from the sub-center 3 within the fixed time, the line, of the sub-center 3 is connected. Also, when the power failure is not detected in the sub-center 3, a power supply abnormality signal is transmitted to a center side system 7. The center side system 7 which receives the power supply abnormality signal requests meter reading stoppage to the terminal equipment 8 and stops the meter reading of the terminal equipment 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides data communication between a terminal side system having a terminal device such as a gas meter connected to a terminal side system and a center side system as an administrator via a telephone line. The present invention relates to a data communication system for collecting information on the terminal side (for example, meter reading information such as a gas meter or security information such as an emergency button) in a center side system.

[0002]

2. Description of the Related Art When data of a plurality of terminal devices, for example, meter reading information of a gas meter is read and collected by an administrator side (center side system) by remote communication using a telephone line, the following data communication system is often used. Has been adopted. Each gas meter of each house is provided with a terminal transmission device having a transmission function and the like, and further a centralized meter reading board that collects signal lines from the terminal transmission device of each house is provided. This centralized meter reading board is connected to the center side system via a public telephone network. Then, the centralized meter-reading board collects the meter-reading information of the gas meter of each house and transmits it collectively to the center-side system for data communication. The power of each terminal transmission device is supplied from a centralized meter reading board equipped with a power failure backup function.

However, in the data communication system provided with the centralized meter reading board, individual wiring work is required between the plurality of terminal transmission devices and the centralized meter reading board. Therefore, it is difficult to introduce the above-mentioned data communication system in an existing apartment house, and recently, a data communication system using a private branch exchange (PBX) used in an apartment house or a building has been widely adopted.

When data communication is performed using this PBX, for example, if no ringing communication is attempted to an extension line, there is a limitation in the line voltage change and timing, so the PBX specifications must be changed, and the cost is reduced. There was a problem that it took time.

A data communication system that solves this problem is disclosed in Japanese Patent Laid-Open No. 265054/1992.
In this data communication system, a sub center is connected to a PBX via an extension line, and the sub center performs data communication between a terminal device and a center side system without passing through the PBX. A terminal device is connected to the extension wired to each door, and a meter such as gas and a home telephone are connected to the terminal device.

When the center side system performs data communication to obtain the meter reading information on the terminal side, first, the center side system calls the sub center directly through the outside line, and the line connection is made between the center side system and the sub center. I do. Next, the center side system transmits a desired terminal device-specific number to the sub-center. Upon receiving the number, the sub center calls a terminal device preset according to the number via the PBX to establish a line connection. In this way, line connection is established between the center-side system and the terminal device via the sub-center, and bidirectional communication is enabled between the center-side system and the terminal device. Then, the meter reading information of the meter connected to the terminal device is collected by the center side system by the communication control by the center side system.

By the way, in a data communication system using the PBX, the subcenter and the terminal device of each house are connected to the PBX.
Since it is only connected by the extension line, it is not possible to supply power to the terminal device from the sub-center, but it is supplied by batteries or AC power of each door.

In a data communication system such as an apartment house, a meter meter is often a pulse meter instead of a microcomputer meter in terms of cost. However, the pulse meter needs to constantly scan the contact terminals, and must always supply power when reading data, so the life of a commonly used lithium battery is short, The battery cannot be used as the power source like the micom meter. Therefore, when using a meter such as a pulse meter that consumes a large amount of battery power, an AC power supply (a power supply supplied from an AC outlet of a general household) is used. Furthermore, an auxiliary power source such as a battery is also used so that data can be read even in the event of a power failure. When a power failure occurs, the auxiliary power source is switched to and data can be read. The power supply to the pulse meter is usually performed from the terminal device to which the pulse meter is connected.

[0009]

In the above data communication system, if the occupant of each house turns off the power breaker that connects and disconnects the AC power when going out, a power failure occurs and the power is switched to the battery. For example, in a student condominium or the like in which a student resides, he / she is often away from home, and sometimes breakers are turned off to go out. At this time, the terminal device to which the pulse meter is connected goes into a power failure state and switches the power source to the battery. Therefore, if a student or the like turns off the breaker during a long vacation such as summer vacation, the battery will be used for a long time. If the contact of the pulse meter is stopped with the make contact kept on, the battery may be consumed unnecessarily.

As described above, conventionally, when the power of the terminal device is turned off, it is uniformly detected as a power failure without distinction between a simultaneous regional blackout and a breaker off, and the power is switched to the battery. ing. Therefore, when the resident turns off the breaker and goes out, he / she will be absent,
Reading of pulse meter is continued by the battery even though gas is not used. As a result, the battery is consumed unnecessarily and the life of the battery is shortened. Moreover, the battery is exhausted, and when it is necessary to perform meter reading, meter reading becomes impossible and accurate meter reading cannot be performed. Therefore, in view of the above, the present invention provides a data communication system capable of extending the battery life and reliably reading the data of a meter or the like by discriminating the original simultaneous local power outage and the power outage due to the breaker being turned off. For the purpose of provision.

[0011]

The problem solving means according to the present invention is to read the data of the terminal equipment, for example, the data of the meter or the abnormal information from the sensor into the terminal side system and transmit it to the center side system via the telephone line. A power outage detecting unit that includes one or more terminal devices that perform the operation, and that is switched to an auxiliary power source when the main power source such as an AC power source is turned off in the terminal device and detects whether or not the main power source of the terminal device is turned off due to a power failure. And a control means for continuing to read the data of the terminal device when there is a power failure and stopping the reading when there is no power failure.

Since the main power supply is turned off temporarily due to a power failure, switching to an auxiliary power supply such as a battery and continuing to read data from the terminal equipment prevents unnecessary battery consumption. Data can be read reliably. In addition, turning off the breaker when there is no other than power outage, turning off the main power supply due to a failure of the terminal device, etc. may take a long time, and there is no data or inaccurate data, so it is necessary to continue reading the data. Instead, you can just stop and eliminate unnecessary battery use.

Specifically, in a data communication system in an apartment house or the like, a terminal side system is a private branch exchange connecting a plurality of terminal devices via extension lines, and a private branch exchange connected to the private branch exchange via extension lines and a center side. It is equipped with a sub-center connected to the system via a telephone line, and a detection unit for detecting a power failure is provided in the sub-center as a power failure detection means.The control means is a power failure caused by turning off the breaker when the power failure is detected by the sub-center. Therefore, the sub center outputs a command to the terminal device to continue reading the data of the terminal device.

Further, a command detecting means for detecting whether or not the terminal device receives an instruction to continue reading the data of the terminal device by the control means within a predetermined time when the main power supply of the terminal device is turned off, and a command. And a transmission means for notifying the abnormality by calling the terminal when not receiving. Further, the control means stops the reading of the data of the terminal device when the power failure is not detected by the sub center even if the main power supply of the terminal device is turned off.

That is, even if the main power supply of the terminal device is turned off, if the power failure is not detected in the sub center, that is, if the breaker is turned off, this can be determined by the command detecting means. Then, in such a case, there is a possibility that an abnormal situation may occur, so that the notification is made. Since the terminal device switches to the auxiliary power source when the main power source is turned off, it can be recognized that the main power source is off.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) As shown in FIG. 2, a terminal side system in a data communication system of the present embodiment is provided with a sub center 3 at an extension 2 of a PBX 1 installed in an apartment house, a building, etc. An external line 5 independent of a telephone line 4 connected to the PBX 1 is connected to the center 3 and directly connected to a center side system 7 via a public telephone network 6. A plurality of terminal devices (terminal NCU) 8 are connected to the extension 2, and terminals such as a pulse meter 9 for detecting the usage amount of gas, water, etc., a sensor 10 for detecting an abnormality such as gas leakage, etc. are provided to the terminal NCU 8. The device and the home telephone 11 are connected.

As shown in FIG. 3, the sub-center 3 includes a CPU 20 for controlling and managing the sub-center 3, a memory 21, a communication modem 22 which is an interface with the external line 5 and the internal line 2, a keyboard, An input / output control circuit 24 connected to an input / output device 23 such as a display
And a power supply switching circuit 27 to which an AC power supply circuit 25 connected to a shared AC power supply such as an apartment and a battery 26 are connected
Are provided.

The CPU 20 has a function of accumulating data supplied from the communication modem 22 connected to the preceding stage in the memory 21, and reading data stored in the memory 21 in response to a signal supplied from the communication modem 22. , A function of outputting the read data via the communication modem 22, a function of connecting the designated terminal NCU 8 to the designated center system 7 when there is a communication request from the center side system 7, and a function of transmitting from the terminal NCU 8. It has a function of analyzing the data and a function of calling the center side system 7 according to the analyzed data.

The power supply switching circuit 27 uses a relay or the like to control the input / output control circuit 2 when the AC power supply is turned off due to a power failure or the like.
4 is switched from the AC power supply circuit 25 to the battery 26. At this time, an AC power supply off signal is output to the CPU 20 via the input / output control circuit 24 to function as a power failure detection unit.

The terminal NCU8, as shown in FIG.
An interface between the main control device 30 which controls itself, a no-ringing receiving circuit 31 which receives a no-ringing signal, a connection switching circuit 32 which connects and disconnects the home telephone 11 to and from the extension 2, and an extension 2. An interface (I / F) 3 that reads a signal from a certain modem 33 and a pulse meter 9 or a sensor 10 or a contact signal of a switch such as an emergency button into the main controller 30.
4, 35 and the reading (meter reading) state of the data of the pulse meter 9 is displayed (for example, when displaying with an LED, the LED is turned on during the meter reading, the LED is turned off while the meter reading is stopped, and when an abnormality such as a gas leak occurs. Display circuit 36 for flashing display)
And a constant voltage circuit 38 connected to the AC power adapter 37
And a power supply switching circuit 40 to which a battery 39, which is an auxiliary power supply at the time of power failure, is connected. In addition, in FIG.
Reference numeral 1 is an on-hook control circuit, and 42 is a selection signal transmission circuit.

The power source switching circuit 40 is a relay or the like when the AC power source in the home to which the AC power source adapter 37 is connected is turned off, that is, when there is a power failure, the AC power source adapter 37 is unplugged, or the breaker is turned off. To switch the power source to the battery 39. At this time, the main controller 30
To the AC power off signal.

As shown in FIG. 5, the main controller 30 includes a CPU 43 which is a central control unit, a timer counter 44 to which a power source switching circuit 40 is connected, and a CPU.
A memory 4 in which a program for issuing a control command is stored in 43
5, a data memory 46 for holding rewrite data to be held in the terminal NCU 8 and temporary data generated internally, and an I / O 4 which is an interface with the outside.
7

The CPU 43 has a function of detecting an off-hook of the home telephone 11, a function of off-hook and no-ringing communication with the home telephone 11 disconnected when the call is made from the sub-center 3, and a line when the ringer is received. 11 has a function of sending a ringer to the home telephone 11 and a function of monitoring a power supply state such that the AC power is off when an AC power off signal is input from the power switching circuit 40.

In this system, the terminal NC
There are provided power failure detection means for detecting whether or not the AC power supply of U8 is off due to a power failure, and control means for continuing the meter reading of the pulse meter 9 when there is a power failure and stopping the meter reading when there is no power failure. Further, when the AC power of the terminal NCU8 is turned off, command detecting means for detecting whether the terminal NCU8 receives a command from the control means within a certain time, and when the command is not received, a call is made to the terminal to make an abnormality. And a transmission means for informing.

The power failure detecting means determines that there is a power failure based on the AC power-off signal output from the power source switching circuit 27 in the case of a simultaneous regional power failure in the sub-center 3. Moreover, since the terminal NCU8 has a function of monitoring the power supply state, when the terminal NCU8 detects that the AC power supply is off,
If the sub-center 3 is not in power failure, it is determined that the AC power supply is turned off due to a cause other than power failure.

In the sub-center 3, when the power failure detecting means detects a power failure, the control means continues the call restriction request command for restricting the call from the terminal NCU 8 and the meter reading of the pulse meter 9. Function to send the meter-reading continuation request command to the terminal NCU8, and send a line hold request command to hold the line with the terminal NCU8 when the AC power supply is off due to a cause other than the power failure, and send the terminal NCU8 and the center side system 7 It has a function of forming a communication path between and, and a function of transmitting a meter reading stop request command from the center side system 7 to the terminal NCU 8 to stop the meter reading of the pulse meter 9.

The command detecting means activates the timer counter 44 in the terminal NCU 8 when the AC power supply off signal is output from the power supply switching circuit 40, and receives the meter-reading continuation request command from the sub-center 3 within a fixed time. It is determined whether or not there is a power failure when it is received within a certain time. As a result, it is possible to detect whether or not the AC power supply is turned off due to a power failure without providing a device for detecting the power failure.

The fixed time in the command detecting means is
It is set to the time until the operation such as the command transmission to all the terminals NCU8 is completed. For example, since the connection time and communication time (T) per one sequence is about 20 seconds, it takes about 16 minutes for an apartment house with 50 units. Therefore, it is desirable to set the certain period of time to a value larger than the value represented by the product of K × T required to complete the communication with all the terminals NCU8 according to the scale of the number of meter-reading units (K) in the housing complex. .

When it is determined that the cause of the AC power-off is other than the power failure, the transmitting means calls the sub-center 3 from the terminal NCU8 to establish a line connection, and the sub-center 3 and the center side system 7 receive a power supply abnormality signal. Is transmitted.

The operation when the AC power supply of the terminal NCU8 is turned off in the above configuration will be described with reference to FIG. When the AC power supply is turned off in any of the terminals NCU8, the power supply switching circuit 40 switches the power supply from the constant voltage circuit 38 to the battery 39 and notifies the CPU 43 that the AC power supply is off. When the CPU 43 recognizes that the AC power supply is off, the timer counter 44 starts counting time.

At this time, in case of power failure, the sub center 3
Also, the AC power is turned off, and the power supply switching circuit 27
Switches the power supply from the AC power supply circuit 25 to the battery 26 and notifies the CPU 20 that the AC power supply is off. Then, the CPU 20 recognizes that the AC power supply is off. That is, it is determined that the entire terminal system has lost power. Then, in order to notify the terminal NCU8 of the power failure, as shown in FIG. 6, the PBX 1 is dialed, and each terminal NCU8 is sequentially called by no ringing communication to connect the line. When the ACK (response signal) from the terminal NCU8 is received and the line connection is completed, the sub-center 3 performs data communication for sending a call restriction request command and a meter reading continuation request command to the terminal NCU8 by the control means. Upon receipt of these commands, each terminal NCU8 restricts calling and further continues the meter reading of the pulse meter 9. When these are completed, the end command is transmitted from the sub-center 3 to the terminal NCU8 to end the communication, and the terminal NCU8 enters the on-hook state. This operation is repeated for each terminal NCU8.

Here, if the command detecting means detects whether or not the command from the sub-center 3 is received, and the command cannot be received even after a lapse of a certain time, the AC power is turned off due to a cause other than the power failure. Conceivable. However, if the home telephone 11 is in use at the time of power failure, the sub center 3
Tries to send a command to the terminal NCU8, the line cannot be connected and the command cannot be sent even after a certain period of time. Therefore, the terminal NCU8 cannot receive the command from the sub-center 3 within a certain time, and cannot recognize that the cause of the AC power supply being turned off is a power failure. When the breaker to which the terminal NCU8 is connected is turned off, the terminal NCU is
Since the turning off of the AC power supply of 8 is not recognized, naturally no command is received from the sub center 3 while the timer counter 44 is counting.

Even if such a fixed time elapses, the terminal NCU
8 cannot receive the command from the sub-center 3,
The terminal NCU8 must confirm with the sub-center 3 whether the cause of the AC power supply being turned off is a power failure or the cause of the terminal NCU8 alone, such as turning off the breaker.

Therefore, as shown in FIG. 7, the terminal NCU8
Dials PBX 1 and calls sub-center 3 to establish a line connection. When the sub-center 3 recognizes a power failure, data communication is performed to send a meter-reading continuation request command to the terminal NCU8. As a result, the terminal NCU
8 recognizes that there is a power failure and continues meter reading. When this operation is completed, the sub center 3 transmits an end command to the terminal NCU 8 and the operation ends.

When the sub-center 3 does not recognize a power failure, the sub-center 3 sends a line hold command to the terminal NCU 8 to hold the line, as shown in FIG. At this time, the terminal NCU8 recognizes that the AC power has been turned off due to the breaker being turned off. The sub-center 3 dials the center-side system 7, receives an ACK from the center-side system 7, and when the line is connected, the sub-center 3 sends the center-side system 7
Send a power failure signal to. When the center side system 7 receives this power supply abnormality signal, it performs data communication for sending a meter reading stop request command to the terminal NCU 8 via the sub center 3. Upon receiving this meter reading stop request command, the terminal NCU 8 stops the meter reading, turns off the LED that is lit during the meter reading of the display circuit 36, and displays that the meter reading is stopped. When these operations are completed, the center side system 7 sends an end command to end the operations. At the same time, all the lines are released by transmitting a line release request command from the terminal NCU 8 to the center side system 7 via the sub-center 3. In this way, when it is recognized that the breaker is turned off and the AC power is turned off, it is determined that the resident has turned off the breaker when he / she goes out, it is determined that he / she is not present, and unnecessary meter reading is stopped.

Regarding the return of the meter reading, since the breaker is turned on when the resident returns home, the AC power is supplied to the terminal NCU8 by this, and the meter reading is automatically executed.

As described above, when the AC power supplied to the terminal NCU 8 is turned off, it is detected whether or not there is a power failure, the meter reading of the pulse meter 9 is stopped when there is no power failure, and the meter reading is continued when there is a power failure. As a result, when the power is not out, the resident determines that the user is absent, and the meter reading is stopped. Therefore, unnecessary battery consumption can be prevented and the battery life can be extended. Therefore, meter reading at the time of power failure can be continued for as long as the battery life becomes longer. When the AC power supply is turned off due to a power failure, the resident is likely to be at home, and it is necessary to continue the meter reading of the meter. By continuing the meter reading, accurate data can be obtained.

Moreover, when the collection time of the meter reading information of the terminal NCU 8 by the center side system 7 or the sub-center 3 is fixed, if the meter reading is not performed at that time, data communication for collecting the meter reading information cannot be performed. ,
Even during a power failure, stable power is supplied from the battery, so meter reading can be continued and data communication can be performed at regular intervals. Therefore, accurate meter reading can be performed regardless of power failure.

Further, since the center side system 7 can obtain the absence information of the resident, when an abnormality such as a gas leak is reported from the terminal NCU8, prompt measures can be taken and safety is enhanced. That is, when an abnormality is notified to the center-side system 7, not only can the gas stopper be closed by remote control, but also personnel can be dispatched to cancel the abnormality, thus maintaining safety.

Even if the AC power supply is turned off due to the failure of the terminal NCU, the meter reading is stopped, so that it is possible to prevent the reading of unreliable data and execute the accurate meter reading.

(Second Embodiment) As shown in FIG. 9, the data communication system according to the present embodiment has a terminal N to which a pulse meter 9, a sensor 10 and a home telephone 11 are connected.
A terminal side system 50 in which a plurality of CUs 8 are collected and a center side system 7 are connected via a public telephone network 6. As a power failure detection means, a power failure detection device 51 connected to the center system 7 via the public telephone network 6 is provided in the terminal system 50. Also,
In the center side system 7, it controls the function of the control means for continuing the meter reading of the pulse meter 9 when there is a power failure and stopping the meter reading when there is no power failure. The rest of the configuration is the same as in the first embodiment.

The power failure detection device 51 is adapted to switch from an AC power source to a battery when a power failure occurs, and can detect a simultaneous regional power failure in the terminal side system. Furthermore, A
It also has a function of calling when the C power source is turned off and notifying the center side system 7 that there is a power failure. The terminal NCU 8 is installed so that it can detect the power-off of the shared power supply.

In the above structure, a telephone line is normally connected to the terminal NCU 8 provided in the terminal side system 50, and the center side system 7 transmits the ringing signal and the ringing signal transmitted from the public telephone network 6 including the exchange. The caller number is obtained by detecting a caller number signal in the form of a telegram inserted during the rest period, compared with the caller number registered in advance, and if it is the system 7 on the center side, it is connected backward from the terminal NUC8. An incoming call is sent to the home telephone 11 without sending a calling signal, and communication is performed with the center side system 7. If it is not the center system 7, the telephone line is connected to the home telephone 11.

However, when the AC power supply of the terminal NCU8 is turned off, the power supply is switched to the battery 39 and the timer counter 44 starts to count as in the first embodiment. At this time, in the case of a power failure, the AC power source is turned off also in the power failure detection device 51, the power source is switched to the battery, and the center side system 7 is called to notify the power failure. As a result, the center side system 7 recognizes that the terminal side system 50 is in a power failure state. The center side system, which recognizes that the terminal side system 50 is in the power failure state, dials the terminal NCU 8 to inform the terminal NCU 8 of the power failure, and sequentially calls each terminal NCU 8 by no ringing communication to connect the line. Then, when the ACK (response signal) from the terminal NCU8 is received and the line connection is completed, the center-side system 7
A command for restricting call origination and continuing meter reading is transmitted to CU8. The terminal NCU 8 which has received this command is restricted from calling and continues to read the pulse meter 9. This operation is repeated for each terminal NCU8.

On the other hand, the terminal NC which recognizes that the AC power is off
In U8, if a command such as continuation of meter reading cannot be received from the center-side system 7 after a certain period of time, the terminal N
The CU 8 makes a call to the center side system 7. Then, when the center side system 7 recognizes the power failure when the communication by the calling is performed, the center side system 7 transmits a command to continue the meter reading to the terminal NCU 8. As a result, the terminal N
The CU 8 recognizes that there is a power failure and continues meter reading.

Further, in response to a call from the terminal NCU8,
When the power failure is not recognized by the center system 7,
The center side system 7 recognizes that the AC power has been turned off by turning off the breaker of the power supply of the terminal NCU8.
Instructs the terminal NCU8 to stop the meter reading. Upon receiving this command, the terminal NCU8 stops the meter reading. The return of the meter reading is the same as that of the first embodiment, and the meter reading is automatically executed when the AC power is restored.

Thus, when there is a power failure, the terminal NCU8
The meter reading of the data of the pulse meter 9 can be continued, and the meter reading can be stopped when there is no power failure, so the consumption of the battery can be prevented,
Accurate data communication can be performed. Also, the terminal NC
Even when the installation location of U8 is not an apartment house, the above effect can be achieved by installing the power failure detection device. In addition,
A power failure detection device may be installed in each terminal NCU8. Also, it is possible to deal with the case where the terminal side system has only one terminal NCU.

It should be noted that the present invention is not limited to the above-described embodiment, and it goes without saying that many modifications and changes can be made to the above-described embodiment within the scope of the present invention. For example, among a plurality of terminals NCU, a terminal (for example, a terminal NCU in the manager's room if it is an apartment house) that does not have the AC power turned off is determined, and the terminal NCU is not turned off. . Then, all the terminals NCU have a function of sending power failure information to the center side system when the AC power is turned off. Then, when the AC power of the special terminal NCU is turned off, the center side system is preferentially called to send the power failure information. As a result, the center system recognizes that there is a power outage. Further, when the power failure is not recognized, the center system recognizes that the breaker in the room of the terminal NCU is turned off when the power failure information is sent from another terminal NCU, and stops the meter reading. That is, the system on the center side is provided with the power failure detection means and the control means.

Further, the main power source may be a DC power source instead of the AC power source. Further, the auxiliary power source may be an emergency power generator other than a battery, and in this case, by stopping the meter reading, unnecessary power consumption can be eliminated.

[0050]

As is apparent from the above description, according to the present invention, a power failure detecting means for detecting whether or not the main power supply of the terminal device is turned off due to a power failure, and the reading of the data of the terminal equipment when there is a power failure. Since there is a control means that continues and stops reading when there is no power outage, even if the main power supply is switched off from the main power supply to the auxiliary power supply when the main power supply is turned off, it is judged that the resident is absent. Can be stopped to reduce the load on the auxiliary power supply. Particularly when a battery is used as an auxiliary power source, unnecessary battery consumption can be prevented and the battery life can be extended.

Further, there is provided a private branch exchange for connecting a plurality of terminal devices via an extension line, and a sub-center connected to the private branch exchange via an extension line and a center side system via a telephone line. As a power failure detection means,
Since the subcenter is equipped with a detection unit that detects a power outage, and when a power outage is detected by the subcenter, the subcenter is equipped with a detection unit that outputs a command to the terminal device to continue reading the data of the terminal equipment. It is useful as a data communication system in, and many terminal devices can be managed by one sub-center, and capital investment can be reduced.

Further, when the main power supply of the terminal device is turned off, the command detecting means for detecting whether or not the terminal device receives within a certain time a command to continue reading the data of the terminal equipment output by the control means. Is provided,
It is possible to detect a power failure and simplify the system without separately providing a device for detecting a power failure. In addition, since the transmitting means is provided to notify the abnormality by calling the terminal when the terminal device does not receive the command, the abnormality can be recognized by a device other than the terminal device, and safety is enhanced.

[Brief description of drawings]

FIG. 1 is a terminal N of the data communication system according to the first embodiment.
Flowchart showing operation when AC power is off in CU

FIG. 2 is a diagram showing the overall configuration of the same data communication system.

FIG. 3 is a block diagram showing a configuration of a sub center.

FIG. 4 is a block diagram showing the configuration of a terminal NCU.

FIG. 5 is a block diagram showing the configuration of a main controller.

FIG. 6 is an operation explanatory diagram when a power failure is detected in the sub center.

FIG. 7 is an operation explanatory diagram when the terminal NCU inquires of the sub-center whether or not there is a power outage.

FIG. 8 is an operation explanatory diagram when the meter reading is stopped.

FIG. 9 is a diagram showing the overall configuration of a data communication system according to a second embodiment.

[Explanation of symbols]

 1 PBX 3 Sub-center 7 Center system 8 Terminal unit (Terminal NCU) 9 Pulse meter

Claims (5)

[Claims] 1. The terminal side system comprises one or a plurality of terminal devices for reading data of the terminal equipment and transmitting the data to the center side system via a telephone line. The terminal devices are auxiliary when the main power supply is turned off. In a data communication system that can be switched to a power source, a power failure detecting means for detecting whether or not the main power source of the terminal device is turned off due to a power failure, and data reading of the terminal device is continued when there is a power failure and read when there is no power failure And a control means for stopping the data communication system. 2. The terminal-side system comprises a private branch exchange for connecting a plurality of terminal devices via extension lines, and a sub-system connected to the private branch exchange via extension lines and to the center-side system via telephone lines. The data communication system according to claim 1, further comprising a center. 3. The power failure detection means is provided with a detection unit for detecting a power failure in the sub center, and the control means reads the data of the terminal equipment from the sub center to the terminal device when the power failure is detected by the sub center. The data communication system according to claim 2, wherein the instruction to continue is output. 4. A command detection for detecting whether or not a command for continuing to read the data of the terminal equipment output by the control means is received by the terminal device when the main power supply of the terminal device is turned off. 3. The data communication system according to claim 2, further comprising means and transmitting means for making a terminal call and notifying an abnormality when the terminal device does not receive the command. 5. The data communication according to claim 3, wherein the control means stops reading the data of the terminal device when a power failure is not detected by the sub center even if the main power supply of the terminal device is turned off. system.