JPH03162059A - Network controller - Google Patents

Abstract

PURPOSE:To reduce current consumption by starting a control means when a polarity inversion signal is detected and a no-ringing call signal is detected and not starting the control means when no no-ringing call signal is detected. CONSTITUTION:A no ringing incoming circuit 11 detects polarity inversion and outputs a polarity detection signal and a timer circuit 23 starts counting. However, in this case since no ringing call signal is not detected, an effective tone detection signal DV resulting from a DTMF receiver 13 starting a CPU 16 is not outputted the CPU 16 continues the stop state. When the state continues and a timer circuit 23 counts a prescribed timeout time T2, a timeout signal is outputted. Thus, the timeout signal is fed to the no ringing incoming circuit 11 via an AND circuit 27 and the no ringing incoming circuit 11 reaches in line open state. Thus, the current consumption is saved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a network control device connected to a telephone line and activated by a no-ringing call signal from an exchange.

(Prior Art) FIG. 7 is a system configuration diagram of a communication system in which this type of network control device is used. As shown in this system,
The network control device 74 is connected to the exchange 72, and is connected in parallel to a plurality of telephones 75 installed in a general household, for example. Further, each network control device 74 is connected to a meter 76 that measures the amount of electricity, gas, etc. used, for example.

Each of these meters 76 is connected to the network control device 7.
4 to the exchange 72, and from the exchange 72 to the center device 71, whereby the center device 71
An automatic meter reading system is constructed in which metering data measured by each meter 76 is collected via an exchange 72, a telephone line, and a network control device 74.

In the automatic meter reading system configured as described above, when the center device calls and connects the network control device 74 to access each meter 76 for data collection, a no-ringing trunk is used to prevent the telephone 75 from ringing. A no-ringing calling method is adopted in which the call is activated by receiving a call to the network control device via (NRT) 73.

The operation of the switching system using the no-ringing calling method is similar to the switching operation when a telephone calls, except that the calling signal after polarity reversal is different. That is, the normal telephone ring signal is 16Hz,
In contrast to the 75V AC signal, the no-ringing call signal uses PB signals (DTMF signals) 0 to 9. The PB signals O to 9 are used to select one of a plurality of network control devices connected in parallel to the telephone line to which the telephone 75 is connected, as shown in FIG. be.

As shown in FIG. 10, the basic circuit configuration of a conventional network control device includes a no-ringing receiving circuit 11 connected to telephone lines Ll and L2.
This detects a certain voltage after the polarity of the DC voltage between the telephone lines L1 and L2 is reversed, for example, a voltage of usually 35 volts or more. In addition, this no-ringing incoming circuit 11 is connected to the 16H signal that is output from the exchange after polarity reversal.
z, 75V telephone ring signal and sets the telephone line in an open state (high resistance state), and if another network control device is selected, the telephone line is set in an open state as described above by an external signal. It has the function of Note that the detection of a telephone ringing signal is usually performed at a voltage higher than a certain level, for example 6.
This is done by detecting a voltage of 0V or higher.

When the no-ringing incoming call circuit 11 detects polarity reversal, this polarity reversal detection signal is supplied to the CPU 16, thereby activating the CPU 16. This causes the CPU 16 to
The TMF receiver 13 and clock generation circuit 15 are activated. Further, the clock generation circuit 15 supplies a clock signal to the DTMF receiver 13, and the DTMF transceiver 17 and modem 12 connected in parallel to the DTMF receiver 13.

The DTMF receiver 13 is connected to the no-ringing receiving circuit 11 via a dubbing capacitor C11, a transformer Tll, and a capacitor C13, and detects the no-ringing call signal NRS supplied via the no-ringing receiving circuit 11. Modem 12 and DTMF
}The transceiver 17 is connected to the no-ringing incoming circuit 11 via a coupling capacitor C11, a transformer Tll, and a capacitor C14 or C12. After answering the incoming call, the modem 12 is used for data transmission between the center device 71 and the meter 76, and is also used for DTM
The F transceiver 17 sends the response signal ANS to the no-ringing call signal to the no-ringing trunk (NRT).
) 73. Note that the clock generation circuit 15 is configured to control clock generation/stop by a clock on/off control signal from the CPU 16.

The operation of the conventional network control device described above is as shown in FIG. 11. When the polarity of the telephone lines L1 and L2 is reversed due to a no-ringing call, this polarity reversal occurs as shown in (a) of FIG.
As shown in (b), the no-ringing incoming call is detected by the incoming call circuit 11, and the CPU 16 is activated. Note that the operation of the CPU 16 is stopped before it is started. When the CPU 16 is activated, the DTMF receiver 13 and the clock generation circuit 15 operate in the no-ringing incoming circuit 11 (c) and (d).
), and enters a state of waiting for reception of a no-ringing call signal NRS.

In this case, if a telephone ring signal or a ring signal from another network control device is detected, the CPU 16 sets the no-ringing incoming call circuit 11 to the line open state, and also controls the operation of the DTMF transceiver 17 and the clock generation circuit l5. then the CPU 16 stops operating.

On the other hand, in the waiting state for the above-mentioned no-ringing paging signal NRS, the DTMF receiver 13 of the network control device
detects a no-ringing call signal NRS addressed to itself, it detects a no-ringing call signal NRS from the exchange.
After confirming that the DTMF receiver 13 has stopped, the DTMF transceiver 17 is started and the response signal A
Send NS. Thereafter, the modem 12 is operated, data is transmitted between the center device and the meter, and the series of communication operations is completed.

(Problem to be solved by the invention) In the above-mentioned no-ringing incoming call, the CPU 16, clock generation circuit 15, DTMF receiver 13, and other circuits frequently operate and stop; This is because they are installed outdoors near the meter and cannot use commercial power; they are battery-powered, and their current consumption must be kept as low as possible. For example, the CPU 16 consumes a current of about several milliamperes during operation, but when the operation is completely stopped, the current can be reduced to about several microamperes. Therefore, when using a long-term network control device, it is essential to minimize the amount of operation of the CPU 16.

However, in the conventional network control device described above,
After the no-ringing incoming circuit 11 detects polarity reversal,
Since the CPU is activated only by the voltage of the telephone line, even in the case of a normal telephone call signal that is not a no-ringing call, the CPU is wasted. There is a problem in that U is started up, increasing wasteful current consumption.

The present invention has been made in view of the above, and its object is to provide a network control device that reduces current consumption by not operating a control unit in the case of a telephone call that is not a no-ringing call. There is a particular thing.

[Structure of the invention]

(Means for Solving the Problems) In order to achieve the above object, a network control device of the present invention is a network control device that is connected to a telephone line and activated by a no-ringing call signal from an exchange. polarity inversion signal detection means for detecting a polarity inversion signal; no-ringing call signal detection means that is activated when the polarity inversion signal detection means detects the polarity inversion signal and detecting the no-ringing call signal; and the no-ringing call signal detection means. A control means that is activated when the means detects a no-ringing call signal, and a setting means that sets the main network control device to an open state when the no-ringing call signal detection means does not detect a no-ringing call signal. The gist is:

(Function) In the network control device of the present invention, when a polarity inversion signal is detected and a no-ringing call signal is detected, the control means is activated, and when a no-ringing call signal is not detected, the control means is activated. The main network control device is left in an open state.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a network control device according to an embodiment of the present invention. The no-ringing receiving circuit 11, modem 12, DTMF receiver 13, clock generation circuit 15, DTMF transceiver 17 and CPU 16 provided in the network control device shown in FIG. It is the same as what is there. That is, the no-ringing incoming circuit 11 is connected to the telephone lines Ll and L2, and the modem 12, DTMF l-transceiver 17 and DTMF receiver 13 are connected to the coupling capacitors C14, C12 or C13 and the transformer T11, respectively.
The clock signal from the clock generation circuit 15 is supplied to the modem 12, the DTMF transceiver 17, and the DTMF receiver 13.

The no-ringing incoming call circuit 11 detects the polarity inversion between the telephone lines Ll and L2 as described above, but this polarity inversion signal is not supplied to the CPU 16 but is supplied to one input of the NAND circuit 21. is supplied to the power-down control terminal PD of the DTMF receiver 13, and is also supplied to the NAND circuit 29 of the clock generation circuit 15.
The clock generation circuit 15 is thereby activated.

Further, the clock signal from the clock generation circuit 15 is outputted via the inverter 31 provided inside.
This clock signal is transmitted to a newly provided timer circuit 23.
is also supplied. This timer circuit 23 has a clear terminal connected to a NAND circuit 25, and the NAND circuit 25 is supplied with a polarity detection signal from the no-ringing incoming call path 11 and a clear control signal from the CPU 16.

Further, the timeout output signal from the timer circuit 23 is supplied to the off control terminal OFF of the no-ringing incoming call circuit 11 via an AND circuit 27.

In addition, the other human power of this AND circuit 27 includes the CPU 16.
The off control signal is supplied from

More specifically, as shown in FIG. 2, the no-ringing incoming call circuit 11 has a diode 33 connected in series to the telephone line L2, and this diode 33 has a first transistor 35 for off control and a polar anti-transistor. A second transistor 37 for detection is connected in series. Also, this second
A resistor 39 is connected between the emitter and the base of the transistor 37, and a predetermined voltage, for example, a Zener voltage of 35 V, is applied between the connection point between the resistor 39 and the base of the transistor 37 and the telephone line L1. A first Zener diode 40 and a resistor 42 are connected in series. Further, a transistor 4 is connected in parallel to the Zener diode 40.
1 is connected, a resistor is connected between the base and emitter of the transistor 41, and a resistor and a diode are connected in series between the base of the transistor 41 and the collector of the second transistor 37. There is. Second
A resistor and a light emitting diode 43d of a photocoupler 43 are connected in series between the collector of the transistor 37 and the telephone line L1, and a phototransistor 43t of the photocoupler 43 is connected in series.
The output from the collector is output as a polarity reversal detection signal, that is, a polarity reversal detection signal via an inverter.

Furthermore, an AND circuit 27 (
1) and the off control signal supplied via the off control terminal OFF is supplied to the base of the third transistor 44 via a resistor.

The collector of the third transistor 44 is connected to the light emitting diode 45d of the phototransistor 45, and when the third transistor 44 is driven and conductive by the off control signal, the light emitting diode of the phototransistor 45 is activated, and the phototransistor 45 is activated. 45 phototransistors 45t are made conductive. When this phototransistor 45t becomes conductive, the transistors 46 and 47 connected in positive feedback between the telephone lines Ll and L2 through the diode 33 become conductive, thereby turning off the first transistor 35 for off control. The line is now open.

Further, as described above, in the circuit consisting of the transistors 46 and 47 which are connected in positive feedback between the telephone lines Ll and L2 via the diode 33, a second zener is connected to the base of the transistor 46 via a resistor. A diode 48 is connected. This second Zener diode 48 has a predetermined Zener voltage, such as 60V, which is higher than the Zener voltage of the first Zener diode, and when a ringing signal of 75V is applied between the telephone lines Ll and L2, , this voltage causes the second Zener diode 48
The transistor 46 becomes conductive through the transistor 46, and the transistor 47 also becomes conductive, thereby turning off the first transistor 35 and opening the line.

Figure 3(a). (b) is a timing chart showing the operations of the no-ringing call receiving circuit 11 when receiving a no-ringing call and when the telephone is ringing, respectively.

First, as shown in FIG. 3(a), telephone lines Ll, L2
When the polarity between them is reversed and this polarity reversal voltage exceeds the Zener voltage of the first Zener diode 40, the telephone line L2 is connected to the diode 33, the first transistor 35, the resistor 39, the resistor 42, and the first Zener diode 40. and a first Zener diode 40 in the path of the telephone line L1.
current flows through the Zener diode, which turns on the second transistor 37 and creates a current loop between the telephone lines Ll and L2 from the transistor 37 through the light emitting diode 43d of the first photocoupler 43. Formally imposing. When a current flows through the light emitting diode 43d and the phototransistor 43 is turned on, a polarity detection signal is outputted from the phototransistor 43t via an inverter as shown in FIG. 3(a).

In this state, when the off control signal is supplied as shown in FIG. 3(a), the transistor 44 is turned on, which causes the second phototransistor 45,
The first transistor 3 via the transistors 46 and 47
5 is turned off, current no longer flows through the first phototransistor 43, and thereby the antipolarity detection signal is turned off.

Also, if the telephone call signal is no-ringing incoming circuit 1
1, as shown in FIG. 3(b),
Similar to the case of no-ringing incoming call in FIG. A polar reversal detection signal is output. Then, when a 16Hz, 75V calling signal is supplied superimposed on this polarity reversal, this 75V causes current to flow through the second Zener diode 48, turning on the transistor 46, 47, and thereby turning on the first transistor. 35 is turned off, and the polar reversal detection signal is also turned off.

The operation of the timer circuit 23 shown in FIG. 1 is shown in FIG. 4. When the clear signal supplied from the CPU 16 is turned off, the timer circuit 23 starts counting clock signals, and when a predetermined time T2 has elapsed, it outputs a timeout signal. , this timeout signal is supplied to the no-ringing incoming circuit 11 via the AND circuit 27, and thereby the no-ringing incoming circuit 1
1 is set to a high resistance state with the same line open, and the operation is stopped. That is, the timer circuit 23 starts after the no-ringing incoming call circuit 11 outputs the antipolarity detection signal.
When a predetermined period of time has elapsed, a timeout signal is output, thereby placing the no-ringing incoming call circuit 11 in an open state.

The DTMF receiver 13, as shown in FIG.
) is detected continuously for a predetermined time T3 or more,
The effective tone detection signal DV and received DTMF signal type data (0 to 9) DO to D4 are output, and these signals are supplied to the CPU 16. Note that the CPU 16 is activated by the valid tone signal DV. Further, when the DTMF receiver 13 is supplied with a power down control signal from the CPU 16 to the power down control input terminal PD, the DTMF receiver 13 stops operating.

Further, as shown in FIG. 6, the clock generation circuit 15
When the NAND circuit 29 is supplied with the anti-polarity detection signal from the no-ringing incoming circuit 11, it operates and outputs a clock signal.

Next, the operation of the network control device configured as described above will be explained in the eighth section.
The operation will be explained with reference to the timing chart shown in FIG.

First, with reference to FIG. 8, the operation at the time of a no-ringing call will be explained. As shown in FIG. 8(a),
In response to the polarity reversal operation from the no-ringing trunk 73 (see FIG. 7) of the exchange 72, the no-ringing receiving circuit 11 detects the polarity reversal and sends the polarity reversal detection signal as shown in FIG. 8 (b).
), this pole-reversal detection signal is supplied to the NAND circuit 21, the NAND circuit 25, and the clock generation circuit 15, thereby causing the clock generation circuit 15 to output the polarity detection signal as shown in FIG.
A clock signal is generated as shown in c), and this clock signal is supplied to each circuit. The polar reversal detection signal supplied to the NAND circuit 21 is inverted and supplied to the power-down control terminal PD of the DTMF receiver 13, thereby causing the D
The TMF receiver 13 starts operating and starts detecting a no-ringing call signal NRS consisting of a DTMF signal.

Further, the polar anti-polarity detection signal supplied to the NAND circuit 25 is inverted and supplied to the clear terminal of the timer circuit 23 to start a counting operation.

DTMF receiver 13 receives no-ringing call signal N
When the RS detection operation is started and a no-ringing call signal NRS for a predetermined time T3 or more is detected, the effective tone detection signal DV and the type data (0 to 9) DO-D4 of the received DTMF signal are converted to (d) in FIG. ). It is output as shown in (e) and supplied to the CPU 16. As a result, C.P.
U16 is activated by the valid tone detection signal DV. Then, the CPU 16 reads the type data (0-9) DO-D4 of the DTMF signal received from the DTMF receiver 13, and checks whether the network control device to which it belongs has been called. If another network control device is called, the CPU 16 outputs the off control signal;
This OFF control signal is supplied to the no-ringing incoming circuit 11 via the AND circuit 27, thereby putting the no-ringing incoming circuit 11 in a high resistance state with four wires open and stopping the operation.

On the other hand, if the network control device to which it belongs is called, the CPU 16 calls the timeout of the timer circuit 23 in order to prevent the no-ringing incoming call circuit 11 from automatically entering the line open state due to the timeout of the timer circuit 23. A clear signal is supplied to the timer circuit 23 via the NAND circuit 25 before time T2, thereby causing the timer circuit 2
Stop operation 3. Further, when the no-ringing call signal NRS is stopped, the CPU 16 supplies a power-down control signal to the power-down control input terminal PD of the DTMF receiver 13 to stop the operation of the DTMF receiver 13. The CPU 6 then sends back a response signal ANS via the DTMF transceiver 17 and further sends back a response signal ANS to the modem 12.
Control data communication via.

Next, referring to FIG. 9, the operation at the time of telephone ringing will be explained. As shown in FIGS. 9(a) and 9(b), the no-ringing incoming call circuit 11 detects polarity reversal and outputs a polarity reversal detection signal, which causes the clock generation circuit 15 and DT
The MF receiver 13 and the timer circuit 23 operate, and the timer circuit 23 starts counting. However, in this case, since the no-ringing call signal NRS is not detected, the DTMF receiver 13 does not output the valid tone detection signal DV for activating the CPU 16, and the CPU 6 continues to be in a stopped state. When this state continues and the timer circuit 23 counts a predetermined timeout time T2, the timer circuit 23 outputs a timeout signal as shown in FIG. The signal is supplied to the no-ringing receiving circuit 11 via the no-ringing receiving circuit 11, thereby putting the no-ringing receiving circuit 11 in a line open state. As a result, the anti-polarity detection signal from the no-ringing incoming circuit 11 is turned off, and the DTMF receiver 13, timer circuit 23, clock generation circuit 15, etc. also stop operating, returning to the initial state.

〔Effect of the invention〕

As explained above, according to the present invention, when a polarity inversion signal is detected and a no-ringing call signal is detected, the control means is activated, and when a no-ringing call signal is not detected, the control means is activated. Since the main network control device is left in an open state without having to do so, when a telephone call is made, for example, a CPU constituting the control means is not activated, so that current consumption can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a network control device according to an embodiment of the present invention, FIG. 2 is a circuit diagram of a no-ringing incoming call circuit used in the network control device of FIG. 4 is a timing diagram showing the operation of the no-ringing incoming call circuit, FIG. 4 is a timing diagram showing the operation of the timer circuit used in the network control device of FIG. 1, and FIG. 5 is a timing diagram of the timer circuit used in the network control device of FIG.
FIG. 6 is a timing diagram showing the operation of the TMF receiver, FIG. 6 is a timing diagram showing the operation of the clock generation circuit used in the network control device of FIG. 1, and FIG. 7 is a system to which the network control device of FIG. 1 is applied. 8 and 9 are timing diagrams showing the operation of the network control device in FIG. 1, FIG. 10 is a block diagram of a conventional network control device, and FIG. 11 is a timing diagram showing the operation of the network control device in FIG. FIG. 4 is a timing chart showing the effect. 11...No-ringing incoming circuit, 13...●DTMF receiver, 15 clock generation circuit, 16 CPU, 23 timer circuit.

Claims (1)

[Claims] A network control device connected to a telephone line and activated by a no-ringing call signal from an exchange, comprising a polarity inversion signal detection means for detecting a polarity inversion signal from the exchange; a no-ringing call signal detecting means that is activated when the no-ringing calling signal is detected and detects the no-ringing calling signal; a control means that is activated when the no-ringing calling signal detecting means detects a no-ringing calling signal; and the no-ringing calling signal detecting means. 1. A network control device comprising: setting means for setting the main network control device to an open state when a no-ringing call signal is not detected.