JP4638363B2 - Terminal network controller - Google Patents

Description

  The present invention relates to a terminal network control device in an automatic remote meter reading system that transmits data from a terminal device such as a meter to a center device through a communication line.

  Electricity, gas, water, etc. are indispensable energy for companies and general households, and safe and reliable supply and management to a huge number of users is a daily issue for suppliers. In the era of liberalization competition, suppliers are required to improve operational efficiency, save costs, and improve customer service.

  Against this background, regular meter visits to users and checking of terminal devices are a heavy burden for suppliers, and may require a balance for users. It was. For this reason, a data communication system that automatically performs meter reading and checking from a remote location using a public telephone line to which most users are subscribed has been introduced, and is beginning to spread to ordinary households. In particular, the development and popularization of automatic remote meter reading and automatic remote diagnosis in the field of city gas and LP gas, where safety effects are important, are remarkable.

  In a conventional automatic meter reading system, a terminal network control device to which a meter is connected and a center device are communicably connected by, for example, a telephone line. When a call signal is input to the terminal network control device through the telephone line, the terminal network control device counts ringing due to the call signal. When the number of calls reaches a predetermined number in advance, the terminal network control device determines that it is a meter reading call from the center device, transmits the terminal, and performs data communication with the center device. At this time, the terminal network control device reads the value of the meter and transmits the data to the center device side.

  Here, a telephone is connected to the terminal network control device. The telephone is located behind (downstream) the terminal network control device with respect to the line. When the telephone connected to the downstream side of the terminal network control device in response to a call from the center device goes off-hook, the telephone line becomes busy and the center device cannot call the terminal network control device. .

  In order to solve this problem, Patent Document 1 proposes to disconnect the downstream side of the terminal network control device when the number of calls reaches a predetermined value. Patent Document 2 describes that when the number of detections of the bell call signal coincides with a set value, data is transmitted to the center device by activation on the terminal side after a certain time. In Patent Document 3, if the number of ringing detections of the bell ringing signal is equal to or greater than a set value, data is transmitted to the center device by activation on the terminal side after a predetermined time.

Further, in Patent Document 4, when the number of ringing detections of a bell ringing signal is less than a set value and the telephone connected to the downstream side of the terminal network control device is off-hooked, the line is monitored for a certain period of time. If an ID (PB signal, data communication signal) is received from the center device during that time, data transmission is performed by activation of the terminal side.
JP-A-8-237385 Japanese Patent Laid-Open No. 9-64991 JP-A-10-79799 JP 2004-201157 A

  In the above-mentioned Patent Document 1, when the telephone goes off-hook when the number of calls is less than a predetermined value, data communication between the terminal network control device and the center device is not realized, and automatic remote meter reading is substantially performed. It becomes impossible.

  In Patent Document 2 and Patent Document 3, when an answering machine is set at home, when the center apparatus calls, the answering machine receives a call when the ringing sound continues several times. Since the ringing does not continue for the set number of times or the set number of times (usually about 15 times), automatic remote meter reading is still impossible.

  In Patent Document 4, when a facsimile machine or the like is connected to the downstream side of the terminal network control device, the facsimile machine goes off-hook in response to the call signal and sends a response signal. The response signal may be congested with the ID signal from the center device. If the terminal network control device cannot identify the ID signal, it cannot communicate with the center device, and automatic remote meter reading cannot be performed.

  In view of the above, the present invention identifies a call from the center device and reliably transmits data to the center device even if a communication device that responds to a call signal such as a facsimile device is connected downstream. An object is to provide a terminal network control device capable of communication.

The present invention relates to a terminal network control device that is connected to a terminal device and a communication device and performs data communication with a center device via a communication line, and passes a call signal and an identification signal from the center device. A blocking means for blocking a signal transmitted from the communication device, a detection means for detecting the presence or absence of an identification signal from the center device, and a communication circuit for transmitting and receiving data are provided, and the blocking means includes the provided the line upstream of the detecting means, wherein the communication circuit is connected to each of the communication line with the detection means via said blocking means, if the communication device is off-hook when receiving the call signal, the self-device in the state of being connected to a communication line, wherein while blocking signal transmitted from the communication device by the blocking means so that the detecting means does not detect cell The signals from the data device is monitored by the detecting means, said detecting an identification signal from the center apparatus by the detection means Then, by the communication device in a state disconnected from the communication line, said center device and the data communication.

Further, when the communication device receives a call signal or a predetermined number of times without off-hook, the terminal network controller is off-hook.

  Thus, when the communication device goes off-hook, the terminal network control device is connected to the communication line and can detect a signal flowing through the communication line. At this time, the communication device is connected to the communication line, and transmits a signal as a response to the call. However, the terminal network control device cuts off the signal from the communication device and receives only the signal from the center device. Therefore, the terminal network control device can detect the identification signal from the center device without being obstructed by the signal from the communication device. During this time, since the communication device remains connected to the communication line, the communication device can be used.

  When the communication device does not go off-hook, the terminal network control device goes off-hook and is connected to the communication line so that a signal from the center device can be received. At this time, the communication device is in a state of being connected to the communication line, but does not respond to the calling signal, and therefore does not transmit a signal.

  That is, in order to realize the above configuration, the terminal network control device monitors the communication line, detects a signal flowing through the communication line, detects a off-hook of the communication device, and the communication line of the communication device. Means for switching the connection to the communication line and disconnecting from the communication line, means for determining whether the call is made from the center device from the detected signal, and transmitting from the communication device when the communication device goes off-hook in response to the call signal And a blocking means for blocking the signal to be detected so that the detection means does not detect it. The blocking means allows the calling signal and the identification signal to pass. That is, only a signal from the center device is received without receiving a signal from the communication device. The detecting means detects the presence or absence of an identification signal from the center device when receiving the calling signal.

  The identification signal from the center device uses a PB signal or a data communication signal. As the PB signal as the identification signal, at least one signal of A, B, C, D that does not exist in the push button of the telephone is used.

  According to the present invention, when a communication device such as a facsimile device that transmits a signal that interferes with reception of the identification signal from the center device is connected, the identification signal from the center device and the signal sent from the communication device Even if the network becomes congested, the identification signal can be reliably received without disconnecting the communication device from the line. Therefore, data communication with the center apparatus can be reliably performed in response to a call from the center apparatus, and the reliability as the data communication system is increased. In addition, since the identification signal can be detected while the communication device is connected to the communication line, the use of the communication device is not hindered and the user is not inconvenienced.

  The automatic remote meter-reading system of this embodiment is shown in FIG. In the center device 1, the host device 2 is connected to the center network control device 3, and the center network control device 3 is a terminal network control device on the terminal 7 side through a public telephone line 4 as a communication line and its exchanges 5 and 6. 8 is connected. The terminal network control device 8 is connected to a communication device 9 such as a telephone and is connected to a terminal device such as a meter 10, a sensor, and a contact device. The communication device 9 is connected to the rear side (downstream side) of the terminal network control device 8 in the telephone line 4. The terminal network control device 8 communicates with the meter 10, for example, and acquires necessary meter reading data. The terminal network control device 8 transmits data to the center device 1 in response to a meter reading request from the center device 1 or by a terminal call. As an example of the communication device 9, a telephone is generally used, but there may be a facsimile apparatus with a telephone function or an answering machine.

  As shown in FIG. 2, the terminal network control device 8 includes a call signal detection circuit 11, a communication circuit 12, a main control device 13, a meter interface circuit 14, an off-hook detection circuit 15, a rear connection switching circuit 16, and a line filter 17. ing.

  The terminal network control device 8 is connected to the telephone line 4, and the call signal detection circuit 11 and the communication circuit 12 are connected to the telephone line 4, and the circuits 11 and 12 are connected to the main control device 13. The main control device 13 is configured by a control circuit including, for example, a microcomputer, and includes a counter 18, a RAM 19 that is a storage device, a timer 20, and the like. The communication circuit 12 has a modem function for mutually modulating / demodulating a data signal and an audible frequency signal flowing through a telephone line.

  The meter 10 is connected to the meter interface circuit 14 via a connection terminal. The meter interface circuit 14 is responsible for the interface between the meter 10 and the main controller 13 and exchanges data.

  The off-hook detection circuit 15 is connected between the telephone line 4 and the communication device 9 and detects whether the communication device 9 is used, that is, off-hook or on-hook. The rear connection switching circuit 16 is configured by a relay, and is interposed between the on-hook detection circuit 15 and the communication device 9. The communication device 9 is switched between the state connected to the telephone line 4 and the state disconnected from the telephone line 4 by the operation of the rear connection switching circuit 16 controlled by the main controller 13. When the communication device 9 is disconnected from the telephone line 4, the communication device 9 is connected to the main control device 13 through the rear connection switching circuit 16. At this time, the main control device 13 can directly detect the off-hook of the communication device 9.

  The call signal detection circuit 11 detects a signal flowing through the telephone line 4. That is, a 16 Hz paging signal transmitted from the telephone line 4 is detected. Furthermore, the identification signal transmitted from the center apparatus 1 is also detected. A line filter 17 is provided on the upstream side of the line of the call signal detection circuit 11. The line filter 17 is interposed between the communication device 9 and the call signal detection circuit 11. The line filter 17 is configured by a coil, blocks a signal transmitted from the communication device 9, and allows a call signal or a signal from the center device 1 to pass. More specifically, when the communication device 9 is a facsimile machine, a called station identification signal (2100 Hz) is transmitted when the communication device 9 is off-hook in response to the calling signal. The line filter 17 blocks the called station identification signal. Then, a PB signal (697 Hz to 1477 Hz) that is a call signal or an identification signal is passed.

  The main control device 13 controls each circuit described above to perform data communication with the center device 1 and enables communication via the telephone line 4 by the communication device 9. In addition, since these controls are well-known techniques, detailed description is abbreviate | omitted.

  Then, the terminal network control device 8 operates according to the behavior of the communication device 9 so that automatic meter reading of the meter 10 can be reliably performed by a call from the center device 1. Therefore, main controller 13 has a function of counting the number of times when a call signal is received from telephone line 4, a function of detecting whether communication device 9 is off-hook when the number of call signals is less than a predetermined number, and communication device. 9 has a function of connecting to the telephone line 4 when an off-hook is detected, and a function of monitoring the telephone line 4 while the communication device 9 is connected to the telephone line 4.

  The main control device 13 has a function of monitoring the telephone line 4 when the communication device 9 does not go off-hook and the telephone line 4 is connected to the telephone line 4 when the received call signal exceeds a predetermined number of times. .

  When the main control device 13 receives the identification signal addressed to itself from the center device 1, the main control device 13 disconnects the communication device 9 to perform data communication with the center device 1, and does not receive the identification signal addressed to itself. A function of disconnecting the connection with the telephone line 4 and canceling the monitoring of the telephone line 4;

  The state in which the terminal network control device 8 is connected to the telephone line 4 means that the telephone line 4 is in a loop state or a half loop state. The loop state is a state in which the terminal network control device 8 is connected to the telephone line 4 with a low impedance, for example, 50Ω to 300Ω. The half-loop state refers to a state where the telephone line 4 is connected with a higher impedance, for example, several kΩ. In the half-loop state, less power is being monitored than in the loop state. Further, there is an advantage that it is difficult to hinder a call of the communication device 9 that is off-hook.

  Next, the operation when a call is made by the terminal network control device 8 having the above function will be described with reference to the flowchart of FIG. When a call signal is input to the terminal network control device 8 through the telephone line 4, the call signal detection circuit 11 detects the call signal. This calling signal passes through the line filter 17.

  First, at step # 10, main controller 13 determines whether or not the number of ringing by the calling signal (number of calls) is equal to or greater than a predetermined number N. If it is less than N, it is determined in step # 15 whether or not the communication device 9 has gone off-hook based on the output from the off-hook detection circuit 15. If not off-hook, return to Step # 10.

  On the other hand, if the communication device 9 is off-hook, the process proceeds to step # 20, where the line 4 is monitored by setting the telephone line 4 in a loop state or a half-loop state. That is, main controller 13 detects the presence or absence of an external signal flowing through telephone line 4 through call signal detection circuit 11. At this time, a signal transmitted when the communication device 9 goes off-hook is blocked by the line filter 17, and the calling signal detection circuit 11 does not detect a signal from the communication device 9. Therefore, only the signal from the center device 1 can be detected.

  If the number of ringing is greater than or equal to N in step # 10, it is determined in step # 30 that the call is from the center device 1, and the terminal network control device 8 goes off-hook. Then, the telephone line 4 is monitored in the loop state.

  In step # 40, if a signal from the telephone line 4 is received during monitoring and is identified as an ID signal addressed to itself from the center apparatus 1, the communication device 9 is disconnected in step # 50, and step # 55. , Communication with the center device 1 is started. When the communication with the center device 1 is completed, the communication device 9 is connected to the telephone line 4 in step # 60.

  When the ID signal addressed to itself cannot be received within a predetermined time, it is timed out and it is determined that the call is not from the center apparatus 1. That is, a call to another terminal network control device 8 or a call to the communication device 9. In step # 65, the loop state or half-loop state is canceled and the process is terminated. When the call is for the communication device 9, the communication device 9 responds and performs communication thereafter.

  In the above-described operation, receiving the ID at step # 40 means receiving an ID that matches the own ID. As the ID signal, for example, a push button signal (PB signal) from the center device 1 or a data communication signal can be used.

  When a PB signal is used as the ID signal, at least one of A, B, C, and D that does not exist in the push button of the telephone may be used. These A, B, C, and D signals are the fourth column of the 4 × 4 matrix, that is, the coordinates (1, 4), (2, 4), (3, 4), on the operation unit of the telephone. Although corresponding to (4, 4), there is no push button at these coordinate points. Therefore, it is not input from the operation unit of the telephone, and it can be surely confirmed that the ID signal is from the center apparatus 1.

  As the identification signal instead of the ID signal, in addition to the PB signal and the data communication signal, an audio signal, that is, an audio signal with a content such as “I will perform meter reading now” may be used. A combination of these PB signal, data communication signal, and audio signal may be used. When a voice signal is transmitted, if a PB signal or a data communication signal is transmitted before and after the voice signal, ID recognition on the terminal network control device side is more reliable than when only a voice signal is transmitted.

  In this way, when the terminal network control device 8 receives an ID signal that is an identification signal from the center device 1, if the communication device 9 is off-hook and connected to the telephone line 4, the communication device 9 sends a response signal. send. If the communication device 9 is a facsimile machine, a called station identification signal is sent as a response signal. Even if this response signal is transmitted, the line filter 17 blocks the response signal. Therefore, main controller 13 can reliably receive the ID signal without being disturbed by the response signal. As a result, the terminal network control device 8 can perform data communication with the center device 1.

  At this time, since the telephone line 4 can be monitored without disconnecting the communication device 9 from the telephone line 4, the monitoring time can be extended. Therefore, even if a delay occurs in the signal from the center device 1, the ID signal can be reliably received.

  That is, in Japanese Patent Application No. 2005-291038 filed earlier by the present applicant, when the communication device goes off-hook within a predetermined number of calls, the main control device temporarily disconnects the communication device, and the loop or half-loop state Monitor the telephone line for a certain period of time. If an ID signal is received from the center apparatus during this fixed time, data communication with the center apparatus is started with the communication device disconnected. Here, the telephone line 4 is monitored only for a certain period of time so that the ID signal can be received.

  Therefore, as described above, by blocking the response signal from the communication device 9, it is possible to receive the ID signal without temporarily disconnecting the communication device 9. As a result, there is no restriction of a fixed time, so that the monitoring time can be extended.

  The main control device 13 can always keep the communication device 9 connected to the telephone line 9 except during communication with the center device 1. Accordingly, the use of the communication device 9 is not hindered, and the user can use the communication device 9 when necessary.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention.

Overall configuration diagram of data communication system of the present invention Block diagram showing schematic configuration of terminal network controller Flow chart of operation of terminal network control device for call

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Center apparatus 4 Telephone line 8 Terminal network control apparatus 9 Communication equipment 10 Meter 11 Calling signal detection circuit 12 Communication circuit 13 Main control apparatus 14 Meter interface circuit 15 Off-hook detection circuit 16 Back connection switching circuit 17 Line filter

Claims (5)

A terminal network control device that is connected to a terminal device and a communication device and performs data communication with a center device via a communication line, and passes a call signal and an identification signal from the center device and from the communication device A blocking means for blocking a signal to be transmitted; a detecting means for detecting the presence or absence of an identification signal from the center device; and a communication circuit for transmitting and receiving data.
The blocking means is provided on the upstream side of the line of the detecting means, and the communication circuit is connected to the communication line together with the detecting means via the blocking means,
Wherein the communication device is off-hook when receiving the call signal, in the state where the own apparatus is connected to the communication line, said detecting means a signal transmitted from the communication device is blocked so as not to detect by the blocking means While monitoring the signal from the center device by the detection means ,
A terminal network control device characterized in that when the detection means detects an identification signal from the center device, the communication device is disconnected from the communication line and data communication is performed with the center device. Wherein when the communication device receives a call signal a predetermined number of times or more without off-hook, the terminal network control device according to claim 1, wherein when the device itself, characterized in that the off-hook. 3. The terminal network control apparatus according to claim 1, wherein a PB signal or a data communication signal is used as the identification signal from the center apparatus. 4. The terminal network control apparatus according to claim 3 , wherein at least one of A, B, C, and D signals that do not exist in the push button of the telephone is used as the PB signal as the identification signal. The terminal network control device according to any one of claims 1-4, meter is connected as the terminal equipment, the automatic remote meter reading system, wherein the facsimile apparatus is connected as a communication device.

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