JPH06121068A - Terminal network controller - Google Patents

Abstract

PURPOSE:To set a gain suitable for a subscriber's line loss even at the time of utilizing general telephone service and no ringing communication service. CONSTITUTION:When a first DC circuit terminating part 15 is terminated, a loss detection part 17 detects the loss of a subscriber's line and switches the gain of a gain switching part 5 and when a second DC circuit terminating part 16 is terminated, the gain of the gain switching part 5 is switched based on the loss which is detected when the first DC circuit terminating part 15 is terminated.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art A conventional terminal network control device 1 is connected to a telephone line 2 as shown in FIG. 3, and has a DC circuit terminating portion 3 for satisfying a DC condition when using a general telephone service. A loss detection unit 4 for detecting a loss on the subscriber line side by detecting the current value of the circuit termination unit 3,
A gain switching unit 5 that switches 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 that performs 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 a data signal.

The operation of the above configuration will be described with reference to FIGS. 3 and 4. When the terminal network control device 1 performs data communication, it is connected to the center terminal 13 via the exchange 11 and the exchange 12, as shown in FIG. by the way,
The subscriber line loss that occurs between the terminal network control device 1 and the exchange 11 differs depending on the home in which the terminal network control device 1 is installed, and the transmission level of the push button signal varies depending on the loss of each subscriber line. It is stipulated in the technical standard of the terminal device. In order to satisfy this requirement, telephone lines 2 are generally used.
The terminal line control device 1 or the voltage appearing at both ends of the terminal network control device 1 at the time of termination is detected to calculate the subscriber line loss and determine the transmission / reception signal gain.

With reference to FIG. 3, the operation when the terminal network control device 1 performs data communication after transmitting by a push button signal will be described. Terminal network control device 1
When making a call, first, the control unit 7 controls the DC circuit termination unit 3 to set the telephone line 2 to 50 Ω which is defined by the technical standard.
To a resistance value between 300Ω and 300Ω. At this time, the current flowing through the DC circuit termination unit 3 is detected by the loss detection unit 4, and the transmission / reception gain of the gain switching unit 5 is set. The gain switching unit 5 is provided with a transmission gain switching unit 8 and a reception gain switching unit 9 for switching the gains of the transmission and the reception. On the other hand, after terminating the DC circuit terminating unit 3, the control unit 7 controls the signal transmitting / receiving unit 6 to send out a push button signal for dialing in order to connect to the center terminal. From the signal transmitting / receiving unit 6 to the gain switching unit 5
When a push button signal is sent to, the gain switching unit 5
Then, the signal is output with the gain set by the loss detector 4.

When the center terminal on the other side and the terminal network control device 1 are connected, data communication by a modem signal is started between the center terminal and the terminal network control device 1. Also at this time,
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, the level regulation of the high group of the push button signal when the wire diameter is 0.65 mm. The horizontal axis is the line loss, but if the loss is read as the line current, it becomes the horizontal axis of the second stage. The calculation conditions at this time are that the voltage of the battery of the exchange is 48V, 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 sent from the terminal network control device 1 to the level regulation of FIG. 5, the gain of the gain switching unit 5 is switched according to the line current. When the line loss is small, the gain of the gain switching unit 5 is reduced to lower the sending level, and when the line loss is large, the gain of the gain switching unit 5 is increased to raise the sending level to satisfy the specified value. I have to. In this example, the line current is 80mA to 50mA
The gain is linearly changed between.

For reference, the relationship between the line loss and the line current under the DC circuit termination condition at the time of no ringing communication is shown in the third stage of 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. In addition, in FIG.
The calculation conditions for the current value shown in the third row on 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. Figure 5
As can be seen from the figure, when using a general telephone service, the current changes largely by about 50 mA while the line loss changes from 0 dB to 7 dB, whereas when using the no-ringing communication service, the line loss changes from 0 dB to 7 dB. Even if it changes to, the line circuit changes only about 2 mA. Therefore, when using the no-ringing communication service, the loss detection unit 4 is configured by detecting the line current as in the conventional case, 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 fluctuation in the power supply voltage inside the exchange, the gain switching unit 5 is detected by detecting the line current.
It is not practical to switch between.

[0008]

However, the above conventional structure has the following problems. 1) When the line current is detected by the same method as in the related art during no ringing communication to switch the gain, the amount of change in the current due to the line loss is small, so that an appropriate gain cannot be set according to the line loss. 2) Even when the push button signal is used as the data signal, the loss detection unit 4 uses the gain switching unit 5
Therefore, independent gains cannot be set when the push button signal is used as a selection signal and when it is used as a data signal, and an appropriate gain for data communication cannot be set.

The present invention solves the above-mentioned problems, and 1)
By making it possible to set an appropriate gain according to the line loss during no ringing communication, and 2) by making it possible to set different gains when the push button signal is used as the selection signal and when it is used as the data signal. The purpose is to enable appropriate gain setting both at the time of transmitting the selection signal and at the time of transmitting the data signal.

[0010]

SUMMARY OF THE INVENTION In order to achieve the first object of the present invention, there are provided first and second DC circuit terminating portions connected to a telephone line for terminating the telephone line, respectively. A loss detecting section for detecting a line loss when the DC circuit terminating section is terminated, and a gain switching section for switching the gain when the first and second DC circuit terminating sections are terminated by the loss detecting section. And are provided.

Further, in order to achieve the second object, a gain setting section for controlling the gain switching section based on the loss information from the loss detecting section and the type information of the transmitted / received signal is further provided.

[0012]

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

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIG. In FIG. 1, the gain switching unit 5, the data transmission / reception unit 6, the transmission gain switching unit 8, and the reception gain switching unit 9 are the same as those in the conventional example, and therefore the description thereof will be omitted. In the terminal network control device 14 of FIG. 1, the first DC circuit terminating unit 15 is a block for terminating the telephone line 2 when performing data communication using a general telephone service. 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 detection unit 17 detects the loss of the subscriber line when the first DC circuit termination unit 15 is terminated and switches the gain of the gain switching unit 5, and
When the second DC circuit terminating unit 16 is terminated, the gain switching unit 5 is switched based on the subscriber line loss when the first DC circuit terminating unit 15 is terminated. Further, the control unit 18 controls the first DC circuit termination unit 15, the second DC circuit termination unit 16 and the signal transmission / reception 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 calling 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 first controls the first DC circuit termination unit 15 to terminate the telephone line 2. At this time, since a general telephone service is used, the first DC circuit termination unit 15 connects the telephone line 2 from 50Ω to 30Ω.
Terminate with 0Ω. At this time, the loss detection unit 17 calculates the loss of the subscriber line from the current flowing through the first DC circuit termination unit 15 or the voltage across the first DC circuit termination unit 15. The gain of the transmission / reception signal of the gain switching unit 5 is determined by the loss calculated by the loss detection unit 17. Next, the control unit 1
Reference numeral 8 controls the signal transmitting / receiving unit 6 to connect with the center terminal which is the other terminal, and causes the signal transmitting / receiving unit 6 to transmit a push button signal. The push button signal transmitted from the signal transmitting / receiving unit 6 is amplified by the gain switching unit 5 by the gain determined by the loss detecting unit 17. Then, when the connection with the center terminal, which is the other party's terminal, is completed, the terminal network control device 14 amplifies both the transmission / reception signals by the transmission / reception gain determined by the loss detection unit 17, and exchanges the data signals.

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

As described above, in the first aspect of the present invention, the proper gain calculated from the loss of the subscriber line is stored when using the general telephone service, and it is difficult to calculate the line loss due to the line current and line voltage. Since this gain is 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 general 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 termination unit 15, the second DC circuit termination unit 16, the loss detection unit 7, the gain switching unit 5, and the data transmission / reception unit 6 of the terminal network control device 19 are the first The description is omitted because it is the same as the component for the purpose of. The gain setting unit 20 receives information on the subscriber line loss from the loss detection unit 17, and the control unit 21
Then, the gain of the gain switching unit 5 is determined by receiving the type information of the transmission / reception signal from. On the other hand, the control unit 21 controls the first and second DC circuit termination units 15 and 16 and the signal transmitting / receiving unit 6,
Further, it outputs to the gain setting section 20 whether the signal currently being transmitted / 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 uses a general telephone service to perform data communication after connecting to the center terminal by a push button signal. When the terminal network control device 19 uses a general telephone service, first, the first DC circuit terminating unit 15 is controlled to terminate the telephone line 2 from 50Ω to 300Ω. At this time, the loss detection unit uses the current flowing through the first DC circuit termination unit 15 to
The loss between the terminal network control device 19 and the exchange is calculated. Next, the terminal network control device 19 sends 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 informs the gain setting unit 20 that the type of the signal currently being transmitted is not the data signal but the selection signal. The gain setting unit 20 sets the gain switching unit 5 to the gain determined by the loss according to the line current when the control unit 21 is notified that the signal currently being transmitted is the selection signal. When the selection signal by the push button signal is sent from the terminal network control device 19, the exchange connects the terminal network control device 19 and the center terminal. As a result, the connection between the center terminal and the terminal network control device 19 is completed and the data communication is started. When transmitting the data signal, the control unit 21 informs the gain setting unit 20 that the signal currently being transmitted is the data signal. As a result, the gain setting unit 20 operates so as to further increase the gain so that the reception level at the center terminal becomes appropriate. As a result, this time, the gain can be set according to the loss between the terminal network control device 19 and the center terminal.

Next, the operation when the terminal network control device 19 receives an incoming 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, the call signal by the push button signal arrives from the exchange after the polarity inversion signal that inverts the polarity of the telephone line 2 arrives, and the terminal network control device 1
9 returns the response signal by the push button signal to complete the no-ringing incoming call. At this time, since push button signals are 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 a data signal 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 at the time of transmission / reception of the selection signal and performs data communication.

As described above, according to the second invention, even when the push button signal is used as both the selection signal and the data signal, the push button signal is used as the selection signal or as the data signal. Depending on whether or not there is a gain, it is possible to set the gain separately. Therefore, it is possible to send the selection signal to the exchange with an appropriate gain, and when sending the data signal, it is possible to set another gain so that the gain is appropriate to the center terminal. There is an effect that both the data signal and the data signal 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 or the line voltage for the line gain. This gain is also used when using the no-ringing communication service, which makes it difficult to calculate loss, so even when using both ordinary telephone service and no-ringing communication service, an appropriate gain that matches the loss of the subscriber line can be obtained. The effect is that it can be set.

Further, in the configuration provided with the gain setting section, even when the push button signal is used as both the selection signal and the data signal, the push button signal is used as the selection signal or is used as the data signal. The gain can be set separately depending on whether or not it is used. Therefore, when the selection signal is sent to the exchange with an appropriate gain, and when the data signal is sent, another gain can be set so that the gain is appropriate for the center terminal. There is an effect that both can be transmitted and received satisfactorily.

[Brief description of 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 configuration 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 a 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]

 5 Gain Switching Section 15 First DC Circuit Termination Section 16 Second DC Circuit Termination Section 17 Loss Detection Section 20 Gain Setting Section

Claims (2)

[Claims] 1. A first DC circuit terminating unit and a second DC circuit terminating unit for connecting to a telephone line and terminating the telephone line respectively, and when the first DC circuit terminating unit is terminated. A terminal network control device comprising: a loss detection unit for detecting a line loss; and a gain switching unit that switches a gain when the loss detection unit terminates the first and second DC circuit termination units. 2. The terminal network control device according to claim 1, further comprising a gain setting unit that controls the gain switching unit based on the loss information from the loss detection unit and the type information of the transmitted / received data signal.