JP2583985B2 - Network control circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention automatically notifies meter reading information of a sensor such as a gas meter to an information center via a public telephone line, and automatically receives a no-ringing call from the information sensor. And a network control circuit capable of notifying sensor information.

2. Description of the Related Art FIG. 3 is a block diagram showing a configuration of an automatic calling system for automatically reporting information such as sensors to an information center via a public telephone line.

In FIG. 3, reference numeral 20 denotes an information center for collecting information from the sensor 27, reference numeral 21 denotes an originating exchange that accommodates the information center 20, reference numeral 22 denotes a public telephone line, reference numeral 23 denotes an incoming exchange that accommodates the home transmission device 24, Is a home transmission device having a terminal transmission function and a network control function, 25 is a network control circuit for transmitting / receiving signals to / from the terminating exchange 23 in the home transmission device 25, and 26 is a terminal transmission control device in the home transmission device 25. Main control circuit with function,
27 is a sensor such as a gas meter.

The conventional network control circuit 25 shown in FIG. 3 is used exclusively for outgoing calls, and when a call is requested on the terminal side, the main control circuit 26 transmits the information of the sensor 27 to the network control circuit 25 and the terminating switch 2.
3. Automatically notified the information center 20 via the public telephone line 22 and the calling exchange 21.

FIG. 4 shows the internal configuration of the conventional network control circuit 25. 1
a and 1b are telephone line connection terminals, 2 is a rectifying diode bridge, 3 is a dial signal transmitting transistor, 8 is a terminal calling transistor, and 9 is a network control unit.

In FIG. 4, when a call request is made on the terminal side, the main control circuit 26 sends a signal to the dial signal sending transistor 3 and the terminal calling transistor 8 to turn on these transistors. These transistors 3,8
Is turned on, the network control unit 9 enters the terminal calling mode.

When the network control unit 9 enters the terminal calling mode, the main control circuit 26
Controls the dial signal transmission transistor 3 to transmit a dial pulse and set up a telephone line between the information sensors 20. Thereafter, information is reported from the main control circuit 26 to the information center 20 via the network control unit 9, the public telephone line 22, and the like.

As described above, the conventional network control circuit 25 has been used as a transmission-only circuit.

Problems to be Solved by the Invention However, there is a problem that the above-mentioned conventional network control circuit cannot automatically receive a no-ringing call from the information center.

In order to solve such a conventional problem, the present invention can automatically send information from a sensor when a call request is made to a terminal side, and automatically receives a no-ringing call from an information center, An object of the present invention is to provide an excellent network control circuit capable of reporting sensor information.

Means for Solving the Problems To achieve the above object, the present invention provides, in addition to a first transistor connected in series to a rectifier diode bridge, a second transistor connected in parallel to the first transistor. , A third transistor, a call is made by turning on the first transistor, and a no-ringing call mode is set by turning on the second transistor, in which the ringing signal switches the telephone line. When the signal is transmitted via the second transistor, the second transistor is turned off and the third transistor is turned on to perform the no-ringing communication.

The present invention has the following operation because it is configured as described above. That is, when a call request is made to the terminal side, the network control circuit according to the present invention automatically makes a call immediately and automatically reports information to the information center via a public telephone line, and also performs a no-ringing call from the information center. Automatically receive incoming calls and provide information. As described above, the network control circuit according to the present invention has both functions of automatic call origination and automatic call termination, and can expand the applicable range of the network control circuit.

Embodiment FIG. 1 is a block diagram showing an embodiment of a network control circuit according to the present invention, and FIG. 2 is a block diagram showing a system configuration of a no-ringing communication service which is currently performed.

In FIG. 2, 20 is an information center, 21 is an originating exchange,
22 is a public telephone line, 23 is an incoming call exchange, 24 is a home transmission device, 25 is a network control circuit, 26 is a main control circuit, 27 is a sensor, 28
Is a no-ringing trunk (NRT) for transmitting and receiving signals to and from the home transmission device 25.

Returning to FIG. 1, reference numerals 1a and 1b denote telephone line connection terminals, 2 denotes a diode bridge for rectification, 3 denotes a transistor for transmitting a dial signal, 4 denotes a transistor for calling and no ringing, and 5 denotes a ringing comprising a resistor and a capacitor. Calling impedance adjusting circuit, 6 is a no-ringing communication transistor, 7 is a no-ringing communication impedance adjusting circuit composed of a resistor and a capacitor, 8 is a terminal calling transistor, 9 is a network control unit, 26
Is a main control circuit, and 27 is a sensor.

Note that the transistor 8 constitutes first switch means, the transistor 4 and the impedance adjustment circuit 5 constitute second switch means, and the transistor 6 and the impedance adjustment circuit 7 constitute third switch means. I have.

(A) In the case of a terminal call, the operation of one embodiment of the present invention will be described with reference to FIG.

When a call request is generated on the terminal side, the main control circuit 26
Turns on the dial signal transmitting transistor 3 and the terminal calling transistor 8 in the network control circuit 25 to set the terminal calling mode. In this terminal calling mode, the main control circuit 26 controls the dial signal transmitting transistor 3 to transmit a dial pulse, and establishes a telephone line with the information center 20. Then, from the main control circuit 26, the public telephone line
The information of the sensor 27 is notified to the information center 20 via 22.

The telephone line can be set by sending a PB signal. In this case, the PB signal is sent from the main control circuit 26 to the terminating switch 23 without emitting a dial pulse from the transistor 3.

(B) In the case of no ringing call, the operation of the embodiment of the present invention will be described with reference to FIGS.

First, an outline of the currently performed no-ringing communication will be described with reference to FIG. When there is a no ringing call from the information center 20, a no ringing trunk 28 associated with the terminating exchange 23 transmits a call signal to the network control circuit 25.

When the main control circuit 26 detects this call signal via the network control circuit 25, the main control circuit 26 performs an automatic call receiving operation, and transmits the information of the sensor 27 via the network control circuit 25, the receiving switch 23, the public telephone line 22 and the calling switch 21. No ringing communication is performed by notifying the information center 20 of the information.

Next, the no-ringing communication operation of one embodiment of the present invention will be specifically described with reference to FIG.

The main control circuit 26 includes the dial signal transmission transistor 3
Then, the no-ringing call transistor 4 is turned on to set the no-ringing call mode.

In the no-ringing call mode, and when there is a call from the information center 20, the no-ringing trunk 28 associated with the terminating exchange 23 transmits a call signal to the network control circuit 25. When the main control circuit 26 detects the call signal addressed to the own device via the network control circuit 25, the main control circuit 26 returns a response signal to the no-ringing trunk 28, and enters a response state. The impedance adjustment circuit 5 adjusts the impedance value to a value suitable for receiving the calling signal.

After receiving the calling signal, the main control circuit 26 turns off the no-ringing calling transistor 4, turns on the no-ringing communication transistor 6, sets the no-ringing communication mode, and responds to polling from the information center 20 without ringing the telephone. Then, the information of the sensor 27 is notified. The impedance adjusting circuit 7 has adjusted the impedance value to a value suitable for receiving the no-ringing communication signal.

According to the present invention, as is apparent from the above embodiment, the conventional network control circuit can only perform an automatic call, but automatically receives a no-ringing call from an information center and receives information. It has the effect of being able to report.

Further, according to the present invention, since the first to third switch means simultaneously control the DC impedance and the AC impedance, respectively, the no-ringing communication can be performed at a low cost.
Since each of the switch means is provided with an impedance adjusting circuit, there is an effect that no ringing communication can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a network control circuit according to the present invention, FIG. 2 is a block diagram showing a system configuration of a no-ringing communication service, and FIG. 3 is a diagram for transmitting information via a public telephone line. FIG. 4 is a block diagram showing the configuration of a conventional automatic calling system for automatically reporting to an information center, and FIG. 4 is a block diagram showing the configuration of a conventional network control circuit. 1a, 1b ... telephone line connection terminal, 2 ... diode bridge for rectification, 3 ... transistor for dial signal transmission,
4 ... No-ringing calling transistor (second transistor) 5 ... Impedance adjustment circuit 6 ...
... No ringing communication transistor (third transistor), 7... Impedance adjustment circuit, 8... Terminal calling transistor (first transistor), 9... Network control unit, 25. …… Main control circuit, 27 ……
Sensor.

Claims (1)

(57) [Claims] 1. A rectifier diode bridge connected to a telephone line, first switch means for turning on and off by a control signal connected in series to the rectifier diode bridge, and a no-ringing calling impedance connected in series A second switch connected in parallel to the first switch together with the adjusting circuit; a third switch connected in parallel to the first switch together with the no-ringing communication impedance adjusting circuit connected in series; A call is initiated by turning on the first switch means, and a no-ringing call mode is set by turning on the second switch means. In this no-ringing call mode, a calling signal is transmitted via a telephone line. The second switch means is turned off when And a network control unit that performs no-ringing communication by turning on the third switch means.