JP2016063486A - Communication system and network controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication system and network controller capable of reducing channel occupancy time in a user's house.SOLUTION: A network controller that is connected to a central device through a communication network and, according to a call signal from the central device, separates a terminal device connected to the network controller from the communication network comprises: means for receiving a predetermined signal to be transmitted once or twice by the central device when having detected connection of the terminal device or the network controller to the communication network; and means for transmitting a response signal to a first predetermined signal to the central device when the terminal device has been connected to the communication network, and transmitting a response signal to a second predetermined signal to the central device when the network controller has been connected to the communication network.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a communication system that transmits a usage amount of water, gas, and the like measured by a meter to a central device using a communication network such as a telephone line, and a network control device used in the communication system.

  Conventionally, there is an automatic meter reading system that performs meter reading by controlling a meter such as gas or water from a remote place using a communication network such as a telephone line. In such an automatic meter reading system, a terminal-side network control device to which a meter is connected and a center-side communication device are connected via a telephone line. The communication device on the center side can communicate with the meter connected to the network control device on the terminal side via a telephone line. For example, the meter measures by transmitting a signal for controlling the operation of the meter. Use amount (meter reading value) of gas, water, etc. obtained through communication. Further, the meter on the terminal side can notify an alarm to the center side through a telephone line when an abnormality such as gas leakage is detected.

  A ringing method is known as one of communication methods in an automatic meter reading system using a public telephone line. In the ringing method, the customer's home phone is connected to the network control device on the terminal side, detects the off-hook / on-hook state of the phone in response to a call (call signal) from the center side, and turns the phone into the telephone line. Control to connect and control to disconnect the telephone from the telephone line.

  For example, in response to a call from the center side, when the center side detects that the terminal side has gone off-hook, the center side notifies the phone via the telephone line of a voice message that the phone should be on-hook. If the terminal-side network control device detects that the phone has gone on-hook after receiving a voice message from the center side, it disconnects the phone from the telephone line, and the network control device on the center side and the network control on the terminal side Line control is performed so that communication with the device is possible. If the telephone does not go off-hook in response to a call from the center side, the network control device on the terminal side automatically performs line control so that communication with the network control device on the center side is possible.

JP-A-6-62132

  Although the center side can detect that the terminal side is off-hook in response to a call from the center side, it cannot determine whether the telephone is off-hook or the network control device is off-hook. For this reason, in the conventional ringing method, a voice message is transmitted from the center side when the terminal side off-hook is detected regardless of whether the telephone is off-hook or the terminal-side network control device is off-hook. In the period when the voice message is reproduced, communication cannot be started, and there is a problem that the line occupation time of the customer's house becomes long.

  This invention is made | formed in view of such a situation, and it aims at providing the communication system and network control apparatus which can reduce the line occupation time of a customer's house.

  The communication system of the present application is connected to a central device and the central device via a communication network, and connects the own device or a terminal device connected to the own device to the communication network in response to a call signal from the central device. In the communication system including the network control device, the central device detects, in response to the call signal, the network control device or the terminal device connected to the communication network, the network control device or Means for transmitting a predetermined signal to the network control device once or twice via the communication network when it is detected that the terminal device is connected to the communication network, the network control device comprising: A means for receiving a predetermined signal transmitted from a central device, and when the terminal device is connected to the communication network, a response signal is transmitted to the central device in response to a first predetermined signal, and the own device communicates with the communication device. When connected to the network Means for transmitting a response signal to the central device for the second predetermined signal, and the central device should disconnect the terminal device when receiving the response signal for the first predetermined signal Means for transmitting voice information to the network control device, and means for starting communication with the network control device without transmitting the voice information when a response signal to the second predetermined signal is received. Is further provided.

  In the communication system according to the present application, when the central device receives a response signal for the first predetermined signal from the network control device, the central device stops transmission of the second predetermined signal and sends the response signal for the first predetermined signal to the central device. When the signal is not received from the network control device, the second predetermined signal is transmitted.

  In the communication system of the present application, the network control device receives a predetermined signal transmitted from the central device when the terminal device is connected to the communication network or when the terminal device is connected to the communication network. Means for counting the elapsed time of the device, means for comparing the measured elapsed time with a threshold value, and whether the received predetermined signal is the first predetermined signal transmitted from the central device according to the comparison result by the means Or a means for discriminating whether the signal is a second predetermined signal.

  In the communication system of the present application, the terminal device is a telephone or a facsimile device, and further includes connection means for connecting a meter for measuring a use amount of a supply medium supplied to a consumer.

  The network control device of the present application is connected to a central device via a communication network, and in response to a call signal from the central device, a terminal device connected to the own device is disconnected from the communication network. When the central device detects a connection to the communication network of the device or the network control device, the central device receives a predetermined signal transmitted once or twice, and the terminal device is connected to the communication network, A means for transmitting a response signal to the central device for the first predetermined signal and transmitting a response signal to the central device for the second predetermined signal when the device is connected to the communication network. It is characterized by that.

  According to the present application, the line occupation time of the customer's house can be reduced.

It is a block diagram which shows the whole structure of the communication system which concerns on this Embodiment. It is a block diagram explaining the structure of a terminal side network control apparatus. It is a timing chart explaining operation | movement when a telephone set goes off-hook with respect to the call from the center side. It is a timing chart explaining operation | movement when a terminal side network control apparatus goes off-hook with respect to the call from the center side. 6 is a flowchart illustrating a procedure of processing executed by the terminal-side network control device according to the first embodiment. It is explanatory drawing explaining the PB signal which concerns on Embodiment 2. FIG. 12 is a flowchart showing a procedure for determining a PB signal in the third embodiment. 10 is a flowchart showing a procedure for determining a PB signal in the fourth embodiment.

Hereinafter, the present invention will be specifically described with reference to the drawings showing embodiments thereof.
(Embodiment 1)
FIG. 1 is a block diagram showing an overall configuration of a communication system according to the present embodiment. The communication system according to the present embodiment includes a center-side device and a terminal-side device connected via a public telephone network N. The center side device includes, for example, a host computer 11 and a center side network control device (C-NCU) 12. The terminal side devices include, for example, a terminal side network control device 21 and a terminal side network control device (T -A telephone 22 and a meter 23 connected to the (NCU) 21 are included. The meter 23 is a terminal device that is installed for each consumer such as a private house, measures the amount of supply medium such as water and gas supplied from a supplier, and outputs a measurement result (meter reading value). . The meter 23 may be configured to be connected to the terminal-side network control device 21 via a wireless slave unit not shown.

  When receiving an incoming call from the center side, the terminal-side network control device 21 performs line control according to the usage status of the telephone set 22. That is, when the telephone 22 goes off-hook when an incoming call is received from the center side, the telephone 22 is connected to the public telephone network N. When the telephone 22 does not go off-hook, the terminal-side network control device 21 itself In the off-hook state, communication between the center side and the terminal side network control device 21 is started. The terminal-side network control device 21 acquires information such as a meter reading value measured by the meter 23 and transmits the information to the center-side network control device 12 via the public telephone network N.

  FIG. 2 is a block diagram illustrating the configuration of the terminal-side network control device 21. The terminal-side network control device 21 includes a control unit 211, a ringer detection unit 212, an off-hook detection unit 213, a latching relay 214, a meter IF unit 215, a communication unit 216, and a line control unit 217. Connected to.

  The control unit 211 includes, for example, a CPU, a ROM, a RAM, a counter, a timer, and the like (not shown), and controls the entire device by causing the CPU to execute a control program stored in advance in the ROM.

  The ringer detection unit 212 detects a signal transmitted through the telephone line 20. In the present embodiment, the ringer detector 212 detects a call signal sent from the center side. The detection result by the ringer detection unit 212 is notified to the control unit 211.

  The off-hook detection unit 213 detects that the telephone set 22 connected to the terminal-side network control device 21 has transitioned from the on-hook state to the off-hook state and that the off-hook state has transitioned to the on-hook state. When the off-hook detection unit 213 detects an on-hook or off-hook by the telephone set 22, the off-hook detection unit 213 notifies the control unit 211 to that effect.

  The latching relay 214 is controlled by the control unit 211 and switches between a state where the telephone 22 is connected to the telephone line 20 and a state where the telephone 22 is disconnected from the telephone line 20.

  A meter 23 is connected to the meter IF unit 215 via a connection terminal. The meter IF unit 215 is responsible for the interface between the meter 23 and the control unit 211, and exchanges signals as necessary. For example, when the terminal-side network control device 21 receives a meter-reading request transmitted from the center-side host computer 11 via the public telephone network N, the control unit 211 sends a control signal related to the meter-reading value acquisition request to the meter IF. The data is transmitted to the meter 23 via the unit 215. Further, the control unit 211 receives a data signal related to the meter reading value transmitted from the meter 23 via the meter IF unit 215.

  The communication unit 216 has a modem function for mutually modulating / demodulating a data signal and an audible frequency signal transmitted through the telephone line 20. The line control unit 217 has a connection circuit that closes the telephone line 20 and puts it into a loop state or a high impedance state (half-loop state). When the terminal-side network control device 21 is in a loop state or a high impedance state with respect to the telephone line 20, the terminal-side network control device 21 is connected to the telephone line 20 and can communicate with the center side. Become.

Hereinafter, operations of the center side network control device 12 and the terminal side network control device 21 will be described.
FIG. 3 is a timing chart for explaining the operation when the telephone 22 goes off-hook for a call from the center side. When a call is made from the center side network control device 12 to the terminal side network control device 21, the terminal side network control device 21 receives a call signal through the telephone line 20. The ringer detection unit 212 of the terminal-side network control device 21 detects the call signal received through the telephone line 20 and notifies the control unit 211 that the call signal has been detected. The control unit 211 counts the number of receptions of the call signal, and determines whether or not the off-hook detection unit 213 detects an off-hook by the telephone set 22 before the number of receptions of the call signal reaches a predetermined number (for example, 10 times). .

  The center-side network control device 12 detects the off-hook by the telephone 22 as a terminal-side response to the call, and the first predetermined signal (for example, a DTMF (Dual-Tone Multi-Frequency) push button signal, hereinafter referred to as a PB signal). ) To the terminal side.

  The terminal-side network control device 21 waits for a PB signal transmitted from the center-side network control device 12 after detecting the off-hook by the telephone set 22. When the off-hook by the telephone 22 is detected, the terminal-side network control device 21 returns a response (for example, a DTMF signal) to the first PB signal transmitted from the center-side network control device 12.

  When the center side network control device 12 receives a response from the terminal side to the first PB signal, the center side network control device 12 determines that the telephone 22 is off-hook and transmits a voice message to the terminal side. The voice message is, for example, “This is XX gas. Called for meter reading of gas meter. Please take down the handset as it is.” Prompt.

  When the telephone set 22 is on-hook, the control unit 211 controls the latching relay 214 to disconnect the telephone set 22 from the telephone line 20 and perform data communication between the terminal-side network control device 21 and the center-side network control device 12. To start.

  FIG. 4 is a timing chart for explaining the operation when the terminal-side network control device 21 goes off-hook for a call from the center side. As described above, when a call is made from the center side network control device 12 to the terminal side network control device 21, the terminal side network control device 21 receives a call signal through the telephone line 20. The ringer detection unit 212 of the terminal-side network control device 21 detects the call signal received through the telephone line 20 and notifies the control unit 211 that the call signal has been detected. The control unit 211 counts the number of receptions of the call signal, and determines whether or not the off-hook detection unit 213 detects an off-hook by the telephone set 22 before the number of receptions of the call signal reaches a predetermined number (for example, 10 times). .

  If the off-hook by the telephone set 22 is not detected before the number of receptions of the ringing signal reaches the predetermined number, the control unit 211 controls the line control unit 217 to put the terminal-side network control device 21 itself in the off-hook state.

  The center-side network control device 12 detects the off-hook by the terminal-side network control device 21 as a response on the terminal side with respect to the outgoing call, and transmits the first PB signal to the terminal side.

  The terminal-side network control device 21 waits for a PB signal transmitted from the center-side network control device 12 after performing off-hook by itself. In this embodiment, when the terminal-side network control device 21 itself goes off-hook, the second-time PB signal is not returned to the first-time PB signal transmitted from the center-side network control device 12. It is configured to wait for a signal.

  When the center side network control device 12 times out without receiving a response to the first PB signal (that is, when a predetermined time has passed since the terminal side off-hook was detected), the center side network control device 12 A signal is transmitted to the terminal side.

  When the terminal-side network control device 21 itself goes off-hook, the terminal-side network control device 21 returns a response to the second PB signal transmitted from the center-side network control device 12.

  When the center side network control device 12 receives a response from the terminal side to the second PB signal, the center side network control device 12 determines that the terminal side network control device 21 is off-hook, omits the transmission of the voice message, and controls the terminal side network control. Communication with the device 21 is started.

  FIG. 5 is a flowchart for explaining a procedure of processing executed by the terminal-side network control device 21 according to the first embodiment. When a call signal is input to the terminal-side network control device 21 through the telephone line 20 (step S101), the control unit 211 determines whether an off-hook by the telephone 22 has been detected through the off-hook detection unit 213 (step S102). ).

  If it is determined that an off-hook has been detected by the telephone 22 (S102: YES), the control unit 211 determines whether a PB signal transmitted from the center-side network control device 12 has been received (step S103). When the PB signal is not received (S103: NO), the control unit 211 waits until the PB signal is received. It should be noted that if the PB signal cannot be received before a predetermined time elapses after the off-hook is detected, the processing according to this flowchart may be terminated.

  If it is determined that the PB signal has been received (S103: YES), the control unit 211 transmits a response to the center-side network control device 12 through the communication unit 216 (step S104).

  Next, the terminal-side network control device 21 receives the voice message transmitted from the center-side network control device 12 through the communication unit 216, and sends the received voice message to the telephone set 22 (step S105). The transmitted voice message is reproduced by the telephone set 22, and the user on-hooks the telephone set 22 in accordance with the voice message. Then, the terminal side network control device 21 starts communication with the center side network control device 12 (step S106).

  On the other hand, when the off-hook by the telephone is not detected in step S102 (S102: NO), the control unit 211 determines whether or not the number of ringing signal receptions is less than a predetermined number (for example, 10 times) (step S107). ). When the number of receptions of the calling signal has not reached the predetermined number (S107: YES), the control unit 211 returns the process to step S102.

  When it is determined that the number of receptions of the paging signal has reached the predetermined number (S107: NO), the control unit 211 puts the terminal-side network control device 21 into an off-hook state (step S108).

  Next, the control unit 211 determines whether or not the PB signal transmitted from the center side network control device 12 has been received twice (step S109). When it is determined that the number of reception of the PB signal is 0 or 1 and the PB signal is not received twice (S109: NO), the control unit 211 waits until the PB signal is received twice.

  If it is determined that the PB signal has been received twice (S109: YES), the control unit 211 transmits a response to the center-side network control device 12 through the communication unit 216 (step S110). Thereafter, the control unit 211 shifts the process to step S <b> 106 and starts communication with the center-side network control device 12.

  As described above, in the first embodiment, when the terminal side responds to the first PB signal transmitted from the center side, a voice message is transmitted to the terminal side in the same manner as in the conventional ringing method. 22 is urged to on-hook, and communication is started when the telephone 22 is on-hooked. On the other hand, when the terminal side responds to the second PB signal without responding to the first PB signal transmitted from the center side, the center side omits the transmission of the voice message. Thereby, the line occupation time of the customer's house can be reduced at least by the reproduction time of the voice message. In addition, since the usage time of the terminal-side network control device 21 can be reduced, the power consumption in the terminal-side network control device 21 can be reduced.

(Embodiment 2)
In the second embodiment, a configuration in which the duration of the PB signal is made different between the first time and the second time will be described. Note that the configuration of the communication system and the basic operations of the center-side network control device 12 and the terminal-side network control device 21 are the same as those in the first embodiment, and thus the description thereof will be omitted.

  FIG. 6 is an explanatory diagram for explaining a PB signal according to the second embodiment. FIG. 6A shows an example of a PB signal transmitted by the center-side network control apparatus 12 according to Embodiment 2, and FIG. 6B shows an example of a PB signal used in a conventional ringing method as a comparative example.

  In the second embodiment, the duration T1 of the first PB signal is different from the duration T2 of the second PB signal. For example, the duration T1 of the first PB signal is 0.5 seconds, the duration T2 of the second PB signal is 3.5 seconds, and the pause time Tr between the first PB signal and the second PB signal Is set to 1.0 seconds. That is, the time T from the rise of the first PB signal to the fall of the second PB signal is 5 seconds.

  On the other hand, in the conventional ringing system, when the center side detects an off-hook on the terminal side, the PB signal is transmitted only once. The duration T ′ of the PB signal in the conventional ringing method is, for example, 5 seconds.

  In this application, when the terminal side responds to the first PB signal transmitted from the center side, a voice message is transmitted to the terminal side to prompt the telephone 22 to be on-hook, and communication is started when the telephone 22 is on-hooked. The configuration is to let For this reason, in the second embodiment, as compared with the conventional ringing method, the demand is equal to the sum of the pause time Tr and the duration T2 of the second PB signal (4.5 seconds in the above example). It is possible to reduce the line occupation time of the house.

(Embodiment 3)
In the third embodiment, a method for discriminating between the first PB signal and the second PB signal by the terminal-side network control device 21 will be described. Note that the configuration of the communication system and the basic operations of the center-side network control device 12 and the terminal-side network control device 21 are the same as those in the first embodiment, and thus the description thereof will be omitted.

  Since the PB signal received by the terminal-side network control device 21 from the center-side network control device 12 is a tone signal based on DTMF, there is a possibility that the terminal-side network control device 21 cannot receive normally due to the influence of noise or the like. In this case, inconsistency may occur in the processing to be executed between the center side network control device 12 and the terminal side network control device 21.

  For example, if the terminal-side network control device 21 cannot receive the first PB signal, it cannot return a response to the PB signal, so the center-side network control device 12 sends the second PB signal to the terminal-side network. It transmits to the control apparatus 21. On the other hand, since the terminal side network control device 21 could not receive the first PB signal, when receiving the second PB signal transmitted from the center side network control device 12, the terminal side network control device 21 recognizes the signal as the first time. If the telephone 22 is off-hook, a response signal is transmitted, and if the telephone 22 is not off-hook, a second PB signal is awaited. That is, although the center side network control device 12 transmits the PB signal twice, the terminal side network control device 21 recognizes that the PB signal is received only once, and therefore receives a response from the terminal side. Even if the center-side network control device 12 attempts to start communication later, the terminal-side network control device 21 is in a state of waiting for the end of the voice message, or conversely, a response to the second PB signal is received from the terminal-side network control device 21. Sometimes it doesn't come back.

  In order to eliminate such processing inconsistency between the center-side network control device 12 and the terminal-side network control device 21, in the third embodiment, the received PB signal is changed based on the reception timing of the PB signal. It is determined whether the signal is a PB signal or a second PB signal.

  FIG. 7 is a flowchart showing a procedure for determining a PB signal in the third embodiment. When a call signal is input to the terminal-side network control device 21 through the telephone line 20 (step S201), the control unit 211 determines whether or not an off-hook has been detected by the telephone 22 or the terminal-side network control device 21 itself ( Step S202). When the off-hook is not detected (S202: NO), the control unit 211 stands by until an off-hook is detected.

  When an off-hook is detected by the telephone 22 or the terminal-side network control device 21 (S202: YES), the control unit 211 starts measuring time (step S203).

  Next, the control unit 211 determines whether or not the PB signal transmitted from the center side network control device 12 has been received (step S204). When the PB signal is not received (S204: NO), the control unit 211 waits until the PB signal is received.

  When determining that the PB signal has been received (S204: YES), the control unit 211 determines whether or not the falling timing of the PB signal is before the set time (step S205). When the PB signal transmitted from the center side network control device 12 has a waveform as shown in FIG. 6A, the delay time τ (for example, about 1.0 to 2.5 seconds) between the center side and the terminal side is set. Considering this, the threshold value (setting time) used for determining the PB signal is set to τ + T / 2 (= about 3.5 to 5.0 seconds), for example.

  When the control unit 211 determines that the falling timing of the PB signal is before the set time (S205: YES), the received PB signal is transmitted from the center-side network control device 12 at the first PB signal. (Step S206). Further, when the control unit 211 determines that the falling timing of the PB signal is after the set time (S205: NO), the received PB signal is a second PB signal transmitted from the center-side network control device 12. It is determined that there is (step S207). As in the first embodiment, the control unit 211 responds to the first or second PB signal depending on whether the telephone 22 detects off-hook or whether the terminal-side network control device 21 detects off-hook. Transmit to the center side and start communication with the center side.

  As described above, since the terminal-side network control device 21 according to the third embodiment performs the determination based on the falling timing (reception completion timing) of the received PB signal, one of the PBs is affected by the influence of noise or the like. Even when the signal cannot be received, it can be determined whether the received PB signal is the first PB signal or the second PB signal, and the subsequent processing is performed accurately. Is possible.

(Embodiment 4)
In the fourth embodiment, another method for determining the first PB signal and the second PB signal by the terminal-side network control device 21 will be described. Note that the configuration of the communication system and the basic operations of the center-side network control device 12 and the terminal-side network control device 21 are the same as those in the first embodiment, and thus the description thereof will be omitted.

  In the fourth embodiment, the PB signal itself transmitted by the center side network control device 12 is differentiated between the first time and the second time. For example, since the PB signal is formed by a DTMF signal in which two frequencies are combined, the first PB signal can be made different from the second PB signal by changing the combination.

  In the fourth embodiment, by detecting the tone (frequency) of the received PB signal, it is determined whether the received PB signal is the first PB signal or the second PB signal.

  FIG. 8 is a flowchart showing a procedure for determining a PB signal in the fourth embodiment. The control unit 211 of the terminal-side network control device 21 determines whether or not a PB signal transmitted from the center-side network control device 12 has been received (step S301). When the PB signal is not received (S301: NO), the control unit 211 waits until the PB signal is received.

  When determining that the PB signal has been received (S301: YES), the control unit 211 identifies the tone of the received PB signal (step S302).

  Next, the control unit 211 determines whether the received PB signal is the first PB signal or the second PB signal based on the tone of the specified PB signal (step S303). After discriminating the PB signal, similarly to the first embodiment, the control unit 211 detects the first or second time depending on whether the telephone 22 detects off-hook or the terminal-side network control device 21 detects off-hook. A response to the second PB signal is transmitted to the center side, and communication with the center side is started.

  As described above, since the terminal-side network control device 21 according to the fourth embodiment makes a determination based on the tone of the received PB signal, it cannot be received due to noise or the like. Even in such a case, it can be determined whether the received PB signal is the first PB signal or the second PB signal, and the subsequent processing can be performed accurately.

  The embodiment disclosed this time is to be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the meanings described above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  For example, in this embodiment, the host computer 11 and the center-side network control device 12 are described as separate devices for the sake of explanation, but the host computer 11 has the function of the center-side network control device 12. May be.

  Further, in the first to fourth embodiments, the configuration in which the terminal side responds in response to a call from the center side is described. However, the terminal side makes a call to the center side, and communication between the terminal side and the center side May be provided, and information such as a meter reading value acquired by the meter 23 may be transmitted to the center side.

  In the first to fourth embodiments, the configuration in which the telephone set 22 is connected to the terminal-side network control apparatus 21 has been described. However, a facsimile apparatus may be connected instead of the telephone set 22, in addition to the telephone set 22. And a facsimile machine may be connected.

  Regarding the above embodiment, the following additional notes are disclosed.

  The communication system of the present application is connected to a central device (12) and the central device (12) via a communication network (N), and the own device or the own device according to a call signal from the central device (12). In a communication system including a network control device (21) for connecting a terminal device (22) connected to the communication network (N), the central device (12) responds to the call signal by the network control device. (21) or means for detecting that the terminal device (22) is connected to the communication network (N), and the network control device (21) or the terminal device (22) is connected to the communication network (N). Means for transmitting a predetermined signal to the network control device (21) once or twice via the communication network (N) when it is detected that the connection is established, the network control device (21), Means for receiving a predetermined signal transmitted from the central device (12) When the terminal device (22) is connected to the communication network (N), a response signal is transmitted to the central device (12) in response to a predetermined signal for the first time, and the own device is transmitted to the communication network (N). And a means for transmitting a response signal for the second predetermined signal to the central device (12), and the central device (12) receives the response signal for the first predetermined signal In this case, when receiving the voice information indicating that the connection of the terminal device (22) should be released to the network control device (21) and a response signal to the second predetermined signal, the voice information is And means for starting communication with the network control device (21) without transmitting.

  In this application, when the terminal side responds to the first predetermined signal (PB signal) transmitted from the central device, a voice message is transmitted to the terminal side in the same manner as in the conventional ringing method, and the terminal device is connected. Release is prompted, and communication is started at the timing when the terminal device releases the connection. On the other hand, when the terminal side responds to the second PB signal without responding to the first PB signal transmitted from the central device, the central device omits the transmission of the voice message. Thereby, the line occupation time of the customer's house can be reduced at least by the reproduction time of the voice message. In addition, the usage time of the network control device on the terminal side can be reduced, and the power consumption can be reduced.

  In the communication system of the present application, when the central device (12) receives a response signal for the first predetermined signal from the network control device (21), the central device (12) stops transmitting the second predetermined signal and performs the first predetermined signal. When a response signal to the signal is not received from the network control device (21), a second predetermined signal is transmitted.

  In the present application, when the terminal side responds to the first PB signal transmitted from the central device, a voice message is transmitted to the terminal side to prompt the terminal device to disconnect, and at the timing when the terminal device disconnects. The communication is started. Therefore, the voice message transmission timing can be advanced as compared with the conventional ringing method, and the line occupation time of the customer's house can be reduced.

  In the communication system of the present application, the network control device (21) is configured such that when the terminal device (22) is connected to the communication network (N) or when its own device is connected to the communication network (N), The means for measuring the elapsed time until the predetermined signal transmitted from the central device (12) is received, the means for comparing the measured elapsed time with a threshold, and the received predetermined signal according to the comparison result by the means And a means for discriminating whether the signal is a first predetermined signal transmitted from the central device (12) or a second predetermined signal.

  In the present application, since the network control device performs the determination based on the reception timing of the predetermined signal, even if one of the predetermined signals cannot be received due to the influence of noise or the like, the received predetermined signal is the first time. It is possible to determine whether the signal is a predetermined signal or a second predetermined signal.

  In the communication system of the present application, the terminal device (22) is a telephone or a facsimile device, and further includes a connection means for connecting a meter (23) for measuring the amount of supply medium supplied to a consumer. And

  In the present application, since the terminal device is a telephone or a facsimile device and includes a means for connecting a meter for measuring the amount of supply medium supplied to a consumer, the present invention can be applied to a meter reading system using a ringing method.

  The network control device (21) of the present application is connected to the central device (12) via the communication network (N), and in response to a call signal from the central device (12), a terminal device ( 22) disconnecting the communication network (N) from the communication network (N), the central device when the connection of the terminal device (22) or the network control device (21) to the communication network (N) is detected. When the device (12) receives a predetermined signal transmitted once or twice, and when the terminal device (22) is connected to the communication network (N), a response signal is sent to the first predetermined signal. Means for transmitting a response signal to the central device (12) in response to a second predetermined signal when the device is transmitted to the central device (12) and connected to the communication network (N). Features.

  In this application, when the terminal side responds to the first predetermined signal (PB signal) transmitted from the central device, a voice message is transmitted to the terminal side in the same manner as in the conventional ringing method, and the terminal device is connected. Release is prompted, and communication is started at the timing when the terminal device releases the connection. On the other hand, when the terminal side responds to the second PB signal without responding to the first PB signal transmitted from the central device, the central device omits the transmission of the voice message. Thereby, the line occupation time of the customer's house can be reduced at least by the reproduction time of the voice message. In addition, the usage time of the network control device on the terminal side can be reduced, and the power consumption can be reduced.

11 Host computer 12 Center side network control device 21 Terminal side network control device 22 Telephone (terminal device)
23 Meter 211 Control unit 212 Ringer detection unit 213 Off-hook detection unit 214 Latching relay 215 Meter IF unit 216 Communication unit 217 Line control unit

Claims (5)

A central device, and a network control device connected to the central device via a communication network and connecting the own device or a terminal device connected to the own device to the communication network in response to a call signal from the central device. In a communication system including:
The central device is
Means for detecting that the network control device or the terminal device is connected to the communication network in response to the call signal;
Means for transmitting a predetermined signal to the network control device once or twice via the communication network when it is detected that the network control device or the terminal device is connected to the communication network;
The network control device
Means for receiving a predetermined signal transmitted from the central device;
When the terminal device is connected to the communication network, a response signal is transmitted to the central device for the first predetermined signal. When the terminal device is connected to the communication network, the second predetermined signal is transmitted. Means for transmitting a response signal to the central unit,
The central device is
Means for transmitting, to the network control device, voice information indicating that the connection of the terminal device should be released when a response signal to the first predetermined signal is received;
The communication system further comprising means for starting communication with the network control device without transmitting the voice information when a response signal to the second predetermined signal is received. The central device is
When a response signal for the first predetermined signal is received from the network control device, transmission of the second predetermined signal is stopped, and when a response signal for the first predetermined signal is not received from the network control device, 2 The communication system according to claim 1, wherein the second predetermined signal is transmitted. The network control device
When the terminal device is connected to the communication network, or when the own device is connected to the communication network, means for measuring an elapsed time until receiving a predetermined signal transmitted from the central device;
Means for comparing the measured elapsed time to a threshold;
And a means for discriminating whether the received predetermined signal is the first predetermined signal transmitted from the central apparatus or the second predetermined signal in accordance with the comparison result by the means. The communication system according to claim 1 or 2. The terminal device is a telephone or a facsimile device,
The communication system according to any one of claims 1 to 3, further comprising connection means for connecting a meter for measuring a use amount of a supply medium supplied to a consumer. In a network control device that is connected to a central device via a communication network and disconnects a terminal device connected to the device from the communication network in response to a call signal from the central device.
Means for receiving a predetermined signal transmitted once or twice by the central device when the connection of the terminal device or the network control device to the communication network is detected;
When the terminal device is connected to the communication network, a response signal is transmitted to the central device for the first predetermined signal. When the terminal device is connected to the communication network, the second predetermined signal is transmitted. Means for transmitting a response signal to the central apparatus.

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