JP3077416B2 - Terminal network controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a terminal network controller connected to a telephone line and performing data communication for automatic meter reading of gas or water using a general telephone service and a no-ringing communication service. .

[0002]

2. Description of the Related Art As shown in FIG. 3, a conventional terminal network control device 1 is connected to a telephone line 2 and satisfies a DC condition when a general telephone service is used. A loss detector 4 for detecting a loss on the subscriber line side by detecting a current value of the circuit terminator 3;
A gain switching unit 5 for switching the gain of the transmission / reception signal according to the loss information of the loss detection unit 4, and a signal transmission / reception unit 6 for performing analog / digital conversion of the transmission / reception signal from the gain switching unit 5.
And a control unit 7 for controlling the DC circuit terminating unit 3 and transmitting and receiving data signals.

The operation of the above configuration will be described with reference to FIGS. When the terminal network control device 1 performs data communication, it is connected to the center terminal 13 via the exchanges 11 and 12 as shown in FIG. by the way,
The loss of the subscriber line between the terminal network control device 1 and the exchange 11 differs for each home where the terminal network control device 1 is installed. It is specified in the technical standards for terminal devices. In order to satisfy this regulation, telephone lines 2
, The loss of the subscriber line is calculated by detecting the current flowing through the terminal network control device 1 or the voltage appearing at both ends of the terminal network control device 1 to determine the gain of the transmission / reception signal.

With reference to FIG. 3, an operation when data communication is performed after the terminal network control device 1 makes a call using a push button signal will be described. Terminal network control device 1
When transmitting a call, first, the control unit 7 controls the DC circuit terminating unit 3 so that the telephone line 2 is connected to the 50Ω defined by the technical standards.
And a resistance between 300Ω and 300Ω. At this time, the current flowing through the DC circuit terminating unit 3 is detected by the loss detecting unit 4, and the transmission / reception gain of the gain switching unit 5 is set. The gain switching section 5 is provided with a transmission gain switching section 8 and a reception gain switching section 9 for switching the respective gains of transmission and reception. On the other hand, after terminating the DC circuit terminating unit 3, the control unit 7 performs control for transmitting a push button signal for dialing from the signal transmitting / receiving unit 6 in order to establish connection with the center terminal. Signal transmission / reception unit 6 to gain switching unit 5
When the push button signal is transmitted to the
In, a signal is output with the gain set by the loss detection unit 4.

When the partner center terminal and the terminal network controller 1 are connected, data communication using a modem signal is started between the center terminal and the terminal network controller 1. Again,
The gain of the gain switching unit is set by the gain determined by the loss detection unit 4.

Next, the relationship between the loss detecting section 4 and the gain switching section 5 will be described with reference to FIG. FIG. 5 shows, as an example of the technical standard, a level definition of a high group of push button signals when the wire diameter is 0.65 mm. The horizontal axis is the line loss. If the loss is read as the line current, the horizontal axis becomes the second stage. The calculation conditions at this time are as follows: the voltage of the battery of the exchange is 48 V, the internal resistance is 440Ω, and the terminal resistance of the terminal network control device 1 is 50Ω. In order to satisfy the push button signal transmitted from the terminal network control device 1 with the level regulation of FIG. 5, the gain of the gain switching section 5 is switched according to the line current. When the line loss is small, the gain of the gain switching unit 5 is decreased to lower the transmission level, and when the line loss is large, the gain of the gain switching unit 5 is increased and the transmission level is increased to satisfy the specified value. I have to. In this example, the line current is between 80 mA and 50 mA
The gain is changed linearly between.

[0007] For reference, the relationship between line loss and line current under the DC circuit termination condition at the time of no ringing communication is shown in the third stage on the horizontal axis of FIG. At this time, the DC condition at the time of no ringing communication defined in the technical condition of the line terminal device 1 is 4 kΩ or more. Also, in FIG.
The calculation conditions of the current value shown in the third row of the horizontal axis are that the voltage of the battery in the exchange is 48 V, the internal resistance is 440 Ω, and the DC resistance of the terminal network control device is 4 kΩ. FIG.
As is clear from the above, when a general telephone service is used, the change in current is large and about 50 mA while the line loss changes from 0 dB to 7 dB. Even if it changes, the line circuit changes only about 2 mA. Therefore, when the no-ringing communication service is used, the loss detection unit 4 is configured by detecting the line current as in the related art, and a slight change in the line current is detected in order to control the gain switching unit 5. There is a need. Further, considering that there is a power supply voltage fluctuation inside the exchange, the gain switching unit 5 is detected by detecting the line current.
Switching between is not practical.

[0008]

However, the above-mentioned conventional configuration has the following problems. 1) When the line current is detected by the same method as in the related art during the non-ringing communication and the gain is switched, an appropriate gain corresponding to the line loss cannot be set because the change in the current due to the line loss is small. 2) Even when a push button signal is used as a data signal, the loss detection unit 4
Therefore, independent gain cannot be set for each of the case where the push button signal is used as the selection signal and the case where the push button signal is used as the data signal, and an appropriate gain for data communication cannot be set.

The present invention solves the above problems, and 1)
It is possible to set an appropriate gain according to the line loss at the time of no ringing communication, and 2) by setting different gains for each of a case where a push button signal is used as a selection signal and a case where it is used as a data signal. It is an object of the present invention to enable appropriate gain setting both when transmitting a selection signal and when transmitting a data signal.

[0010]

SUMMARY OF THE INVENTION In order to achieve the first object, the present invention provides a general telephone service connected to a telephone line.
Terminate the telephone line under DC conditions when using
A first DC circuit terminating section for no-ringing communication.
DC conditions when performing data communication using
When the second DC circuit termination for terminating the telephone line, the first DC circuit terminal end is terminated
By detecting the current value of the first DC circuit termination,
A loss detection unit for detecting a line loss on the subscriber line side of the telephone line , the first DC circuit termination unit and the second
Loss detection when both DC circuit terminations are terminated
The transmission / reception signal has a predetermined gain according to the loss information of the unit.
And a gain switching section for performing switching.

Further, in order to achieve the second object, the loss information from the loss detector and the transmission / reception signal are selected signals or data.
Further, a gain setting unit for controlling the gain switching unit based on the data signal type information is further provided.

[0012]

According to the present invention, when the first DC circuit terminating section is terminated by the above configuration, the loss detecting section detects the loss of the subscriber line and switches the gain of the gain switching section.
When the second DC circuit terminator is terminated, the first
The gain of the gain switching unit is switched based on the loss detected when the DC circuit termination unit is terminated. on the other hand,
In the configuration provided with the gain setting unit, the operation of the gain switching unit is controlled based on the loss information of the loss detection unit and the signal type information indicating whether the transmission / reception signal is a selection signal or a data signal.

[0013]

An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, a gain switching unit 5, a data transmission / reception unit 6, a transmission gain switching unit 8, and a reception gain switching unit 9 are the same as those in the conventional example, and thus description thereof is omitted. In the terminal network controller 14 of FIG. 1, a first DC circuit terminating unit 15 is a block for terminating the telephone line 2 when performing data communication using a general telephone service, and a second DC circuit terminating unit. The unit 15 is a block for terminating the telephone line 2 when performing data communication using the no-ringing communication service. Further, the loss detecting section 17 detects the loss of the subscriber line when the first DC circuit terminating section 15 is terminated, switches the gain of the gain switching section 5, and
When the second DC circuit terminating section 16 is terminated, the gain switching section 5 is switched based on the subscriber line loss when the first DC circuit terminating section 15 is terminated. Further, the control unit 18 controls the first DC circuit terminating unit 15, the second DC circuit terminating unit 16, and the signal transmitting / receiving unit 6.

The operation of the above configuration will be described with reference to FIG. First, a case will be described in which the terminal network control device 14 performs a call operation using a general telephone service and then performs data communication. When the terminal network control device 14 performs a calling operation, the control unit 18 controls the first DC circuit terminating unit 15 to terminate the telephone line 2 first. At this time, since a general telephone service is used, the first DC circuit terminating unit 15 changes the telephone line 2 from 50Ω to 30Ω.
Terminate with 0Ω. At this time, the loss detecting unit 17 calculates the loss of the subscriber line from the current flowing through the first DC circuit terminating unit 15 or the voltage across the first DC circuit terminating unit 15. The gain of the transmission / reception signal of the gain switching unit 5 is determined based on the loss calculated by the loss detection unit 17. Next, the control unit 1
Reference numeral 8 controls the signal transmission / reception unit 6 to connect to the center terminal, which is the terminal on the other end, and causes the signal transmission / reception unit 6 to transmit a push button signal. The push button signal transmitted from the signal transmission / reception unit 6 is amplified by the gain switching unit 5 by a gain determined by the loss detection unit 17. Then, when the connection with the center terminal, which is the destination terminal, is completed, the terminal network control device 14 amplifies both the transmission and reception signals by the transmission and reception gain determined by the loss detection unit 17, and exchanges data signals.

Next, a description will be given of data communication when there is an incoming call at the terminal network control device 14 using no ringing communication. When there is an incoming call at the terminal network control device 14 using the no ringing communication service, a call signal by a push button signal arrives after the polarity of the telephone line 2 is inverted, and the terminal network control device 14 When it is confirmed that it is addressed to itself, a response signal is transmitted by a push button signal, and the incoming call from the destination terminal is completed. The gain switching of transmission and reception, which is a point of the present invention, will be described. The terminal network controller 14 receives the push button signal after the polarity inversion has occurred due to the incoming call. The gain for the reception at this time depends on the first DC circuit termination when using a general telephone service. It is determined by the loss detected when the unit 15 is terminated. Also,
When it is confirmed that the call signal by the push button signal is addressed to itself due to no ringing reception, the control unit 1
Reference numeral 8 controls the second DC circuit terminating unit, and terminates the telephone line 2 with a high resistance of 4 kΩ or more. Then, a response signal by the push button signal is transmitted, and the no-ringing incoming call is completed. When the connection with the destination center terminal is completed, data communication by a modem signal is performed.

As described above, in the first invention, when a general telephone service is used, the appropriate gain calculated from the loss of the subscriber line is stored, and it is difficult to calculate the line loss based on the line current and the line voltage. Since this gain is also applied when using the no-ringing communication service, it is possible to set an appropriate gain that matches the loss of the subscriber line even when using both the ordinary telephone service and the no-ringing communication service. effective.

Next, another embodiment of the present invention will be described with reference to FIG. In FIG. 2, the first DC circuit terminating unit 15, the second DC circuit terminating unit 16, the loss detecting unit 7, the gain switching unit 5, and the data transmitting / receiving unit 6 of the terminal network control device 19 are: The description is omitted because it is the same as the component for the purpose of (1). The gain setting unit 20 receives the information of the subscriber line loss from the loss detecting unit 17 and
To determine the gain of the gain switching unit 5 from the information on the type of the transmission / reception signal. On the other hand, the control unit 21 controls the first and second DC circuit terminating units 15 and 16 and the signal transmitting / receiving unit 6,
Further, it outputs to the gain setting unit 20 whether the signal currently being transmitted or received is a selection signal or a data signal.

The operation of the above configuration will be described.
First, a case will be described in which the terminal network control device 19 performs data communication after connecting to the center terminal by a push button signal using a general telephone service. When the terminal network controller 19 uses a general telephone service, first, the first DC circuit terminating unit 15 is controlled to terminate the telephone line 2 at 50Ω to 300Ω. At this time, the loss detection unit detects a current flowing through the first DC circuit
The loss between the terminal network control device 19 and the exchange is calculated. Next, the terminal network control device 19 sends out a push button signal to the exchange to establish a connection with the center terminal. The control unit 21 controls the signal transmission / reception unit 6 to send a push button signal to the exchange. At the same time,
The control unit 21 notifies the gain setting unit 20 that the type of the signal currently being transmitted is not a data signal but a selection signal. The gain setting unit 20 sets the gain switching unit 5 to a gain determined by a loss corresponding to the line current when the control unit 21 is notified that the signal currently being transmitted is a selection signal. When the selection signal based on the push button signal is transmitted from the terminal network controller 19, the exchange connects the terminal network controller 19 and the center terminal. This completes the connection between the center terminal and the terminal network control device 19, and shifts to data communication. When transmitting a data signal, the control unit 21 notifies the gain setting unit 20 that the signal currently being transmitted is a data signal. Thus, the gain setting unit 20 operates to further increase the gain so that the reception level at the center terminal becomes appropriate. As a result, the gain can be set in accordance with the loss between the terminal network control device 19 and the center terminal.

Next, the operation when the terminal network controller 19 receives a call using the no-ringing communication service and performs data communication will be described. In the incoming call using the no-ringing communication service, as described above, after a polarity inversion signal in which the polarity of the telephone line 2 is inverted arrives, a call signal by a push button signal arrives from the exchange, and the terminal network controller 1
9 returns a response signal by the push button signal, thereby completing the no-ringing termination. At this time, since the push button signal is exchanged between the terminal network control device 19 and the exchange, the control unit 21 controls the gain setting unit 20 to switch to the gain of the selection signal. On the other hand, when the connection by the no-ringing incoming call is completed and the center terminal and the terminal network control device 19 are connected, the terminal network control device 19 exchanges data signals with the center terminal. Therefore, at this time, the control unit 21
Informs the gain setting unit 20 that the signal currently being transmitted / received is a data signal, and the gain switching unit 5 determines the gain of the transmission / reception signal with a gain different from that used when transmitting / receiving the selection signal, and performs data communication.

As described above, according to the second aspect, even when the push button signal is used for both the selection signal and the data signal, the push button signal is used as the selection signal or used as the data signal. The gain can be set separately depending on whether or not there is a gain. Therefore, the selection signal can be transmitted with an appropriate gain to the exchange, and when transmitting the data signal, another gain can be set so that the gain becomes appropriate to the center terminal. And data signals can be transmitted and received well.

[0021]

As described above, the terminal network control device of the present invention stores the proper gain calculated from the loss of the subscriber line when using a general telephone service, and uses the line current and the line voltage to store the appropriate gain. This gain is also used when using the no-ringing communication service where it is difficult to calculate the loss, so even when using both the general telephone service and the no-ringing communication service, the appropriate gain that matches the loss of the subscriber line is used. There is an effect that setting can be performed.

Further, in the configuration provided with the gain setting section, even when the push button signal is used for both the selection signal and the data signal, the push button signal is used as the selection signal or used as the data signal. Gain can be set separately depending on whether Therefore, the selection signal can be transmitted to the exchange with an appropriate gain, and when transmitting the data signal, another gain can be set so that the gain becomes appropriate to the center terminal. Has the effect that both can be transmitted and received satisfactorily.

[Brief description of the drawings]

FIG. 1 is a block diagram of a terminal network control device according to an embodiment of the present invention.

FIG. 2 is a block diagram of a terminal network control device in another embodiment of the device.

FIG. 3 is a block diagram of a conventional terminal network control device.

FIG. 4 is a diagram showing connection with a center terminal;

FIG. 5 is a diagram showing a transmission level regulation of a push button signal in a technical standard of a line terminal device.

[Explanation of symbols]

 Reference Signs List 5 Gain switching unit 15 First DC circuit terminal unit 16 Second DC circuit terminal unit 17 Loss detection unit 20 Gain setting unit

Claims (2)

(57) [Claims] 1. A general telephone service connected to a telephone line.
A first DC circuit termination for terminating the telephone line in DC conditions for use, non-ringing communication service
DC conditions when performing data communication using
A second DC circuit terminator for terminating the telephone line ;
Wherein when said first DC circuit terminal end is terminated
By detecting the current value of the first DC circuit termination section,
A loss detecting unit for detecting a line loss on the subscriber line side of the telephone line, the first DC circuit terminating unit and the second straight line terminal;
Both when the flow circuit terminal is terminated,
A terminal network control device comprising: a gain switching unit that switches a transmission / reception signal to have a predetermined gain based on loss information . 2. Loss information and transmission / reception signals from a loss detector.
A gain setting unit for controlling a gain switching unit based on type information indicating whether the signal is a selection signal or a data signal.
The terminal network control device as described in the above.