JPH10271233A - Terminal network controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To considerably reduce the lack current of an entire modem by eliminating current consumption in the part other than a digital part at the time of waiting. SOLUTION: Since connection/disconnection of a ground terminal of an analog part 6 is controlled by a modem switch part 11, the current consumption at the time of waiting of the analog part 6 can be reduced. A ground terminal of a modem reference power supply part 20 is controlled in the same manner as the ground terminal of the analog part 6 by the switch part 11. Even if the current flowing to a transistor constituting the modem switch part 11 is changed to cause the variation of the collector-emitter voltage, the reference voltage of the modem reference power supply part 20 and the ground of the analog part 6 are changed in the same direction by the same extent. Thus, the high-precision stable reference voltage can be supplied to the analog part 6.

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 mainly connected to an analog telephone line.
In particular, the present invention relates to a terminal network control device that controls communication between a meter and a center terminal by automatic meter reading or the like.

[0002]

2. Description of the Related Art FIG. 3 shows a block diagram of a conventional terminal network control device. In FIG. 3, reference numeral 1 denotes a center terminal which is installed in a management center for managing automatic meter reading and the like and communicates with the terminal network control device 18 via a telephone line 2, 2 denotes a telephone line, and 3 denotes a DC resistance viewed from the telephone line 2. A line termination unit for matching AC impedance and transmitting / receiving signals; 4, a modem unit comprising an analog unit 6 and a digital unit 7; 5, a microcomputer unit for controlling the terminal network control unit 18; The analog section 7 modulates transmission data from the section 5 and demodulates reception data from the line terminating section 3. The analog section 7 converts a signal transmitted from the microcomputer section 5 into a first meter interface section 22 or a second meter interface section 23. Digital section 8 for branching, telephone line 2
A line voltage detector for identifying the line state to the microcomputer unit 5 by detecting the voltage of the telephone line 9; a polarity reversal detector 9 for detecting the polarity reversal of the telephone line 2 and notifying the microcomputer unit 5 of the inversion after detection; Reference numeral 10 denotes a battery voltage drop detecting unit for detecting a voltage drop of the battery 16 and notifying the microcomputer unit 5 of the detection, 13 a relay for controlling connection / disconnection between the telephone line 2 and the telephone 17 side, and 14 a relay 1
3, a relay driver unit for performing drive control of 3, a relay driving capacitor 15 for supplying power when driving the relay, 16 a battery, 17 a telephone, 18 a terminal network control device, 19 a line voltage detection unit 8 A line interface unit comprising a polarity reversing unit 9, a battery voltage drop detecting unit 10, and a relay driver unit 14. The line interface unit 20 measures the flow rate of gas and the like and communicates with the center terminal 1 via the terminal network control unit 18 such as meter reading data. A first meter 21 measures the flow rate of gas and the like, and a second meter communicates with the center terminal 1 via the terminal network control device 18 for meter reading data and the like, and 22 communicates with the first meter. , A second meter interface unit for controlling communication with the second meter, and a power supply terminal for the analog unit 6 and the digital unit 7 A substrate resistance generated on IC process structure of the N-type substrate.

Next, the operation of the conventional terminal network controller will be described with reference to FIG. Normally, when performing automatic meter reading of the meter 7, a no-ringing communication service is used. When the reversal detecting unit 9 detects the reversal of the polarity of the telephone line 2, the terminal network control unit 18 notifies the microcomputer unit 5 of the inversion and detects the reversal.
Is in the operating state. And the no ringing call signal (N
RS), a response signal (AN
S) to the telephone line 2. Thus, the center terminal 1
And the terminal network controller 18 enter a communication state. In the communication state, the received signal from the center terminal 1 is demodulated by the analog unit 6 of the modem unit 4, and when communicating with the first meter 20, the microcomputer unit 5 controls the digital unit 7 to change the transmission path. Switching to the first meter interface unit 22 is performed, and the first meter interface unit 22 transmits the signal to the first meter 20.

Conversely, when the meter 20 transmits a signal, the data signal transmitted via the first meter interface unit 22 is modulated by the analog unit 6 and is transmitted to the center terminal 1.
Sent to. Next, from the first meter 20 to the center terminal 1
When communication is desired, the first meter 20 informs the microcomputer unit 5 via the first meter interface unit 22 that terminal communication is to be performed. Next, the microcomputer unit 5 detects the voltage state of the telephone line 2 by the line voltage detection unit 8 to detect whether the telephone 17 connected to the terminal network control device 18 is currently in use, and if not, the relay unit By controlling the driver unit 14, the relay 13 is driven by the power of the relay driving capacitor 15, and the connection between the telephone line 2 and the telephone 17 is disconnected. Then, the telephone line 2 is closed by the line terminating unit 3 and dialing is performed, and thereby communication with the center terminal 1 is performed. After the communication, the relay 13 is driven by controlling the relay driver 14 again to connect the telephone line 2 to the telephone 17 side. The voltage drop of the battery 16 is detected by the microcomputer unit 5 controlling the battery voltage drop detection unit 10. If the battery voltage has dropped, the battery voltage drop detecting section 10 notifies the microcomputer section 5 of the drop.

[0005]

However, in order to use the terminal network control device for a long period of time, it is necessary to reduce the current consumption of the modem unit during standby. However, the modem unit is set to the power saving mode during standby. However, the leakage current leaks from the internal transistor constituting the modem unit, and the current consumption during standby cannot be reduced. Therefore, a method has been considered in which the power supply terminal of the modem section is controlled to be turned on / off by an external transistor. Therefore, if the switching function of the meter interface section is built in the digital section of the modem as shown in the conventional example, it is necessary to always turn on only the digital section. It is not possible to reduce the leak current simply by doing. In addition, if a configuration is used in which a switch by a transistor is connected to the ground terminal of the analog section to perform on / off control, when a reference voltage is supplied to the analog section, the current flowing through the transistor changes, causing variations in the collector-emitter voltage. This causes the accuracy of the reference voltage to deteriorate.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is to control connection and disconnection of a ground terminal of an analog section by a modem switch section. According to the present invention, only the digital section consumes current during standby, so that the leakage current of the entire modem is greatly reduced.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention comprises an analog section for modulating and demodulating transmission data, a digital section for controlling transmission and reception of digital signals, and an IC on an N-type substrate. And a modem switch unit for controlling connection / disconnection of the ground terminal and the ground of the analog unit. By controlling the connection and disconnection of the ground terminal of the analog unit by the modem switch unit, the current consumption of only the digital unit during standby is reduced, so that the leakage current of the entire modem can be significantly reduced.

In addition, an analog section which operates by receiving a reference voltage from the outside is provided with a modem reference power supply section for supplying a reference voltage based on a ground terminal of the analog section. By setting the ground terminal of the modem reference power supply, which should be connected to the ground, to be the same as the ground terminal of the analog switch in the modem switch, the current flowing through the transistor constituting the modem switch changes and the collector-emitter voltage varies. Occurs, the reference voltage of the modem reference power supply unit and the ground of the analog unit change in the same direction and the same magnitude, so that a highly accurate and stable reference voltage can be supplied to the analog unit.

An embodiment of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a block diagram of a terminal network control apparatus according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 1 denotes a telephone line installed at a management center for managing automatic meter reading and the like.
Center terminal that communicates with the terminal network control device 18 via
Is a telephone line, 3 is a line termination unit for matching DC resistance and AC impedance seen from the telephone line 2 and transmitting and receiving signals, 4 is a modem unit composed of an analog unit 6 and a digital unit 7, and 5 is a terminal network. A microcomputer unit for controlling the control unit 18, an analog unit 6 for modulating the transmission data from the microcomputer unit 5 and demodulating the reception data from the line termination unit 3, and a first unit 7 for transmitting a signal transmitted from the microcomputer unit 5. A digital section for branching to the meter interface section 22 or the second meter interface section 23, a line voltage detecting section 8 for detecting the voltage of the telephone line 2 to identify the line state to the microcomputer section 5, and a 9 for the telephone line 2 The polarity reversal detection unit 10 detects the reversal of the polarity and notifies the microcomputer unit 5 of the reversal after the detection by an interrupt. A battery voltage drop detecting unit for notifying the microcomputer unit 5 of this, a modem switch unit 11 for controlling connection / disconnection between the ground terminal of the analog unit 6 and the ground, and 13 for connecting / disconnecting the telephone line 2 and the telephone 17 side. , A relay driver for controlling the driving of the relay 13, a relay driving capacitor 15 for supplying power when driving the relay, 16 a battery, 17 a telephone, and 18 a terminal network control device. , 19 are a line interface unit including a line voltage detecting unit 8, a polarity reversing unit 9, a battery voltage drop detecting unit 10, and a relay driver unit 20, and 20 is for measuring a flow rate of gas and the like and via a terminal network control unit 18. A first meter 21 for communicating meter reading data and the like with the center terminal 1 measures a flow rate of gas and the like, and via a terminal network controller 18. A second meter for communicating meter reading data and the like with the center terminal 1, a first meter interface unit 22 for controlling communication with the first meter, and a second meter 23 for controlling communication with the second meter. Is a board resistance generated between the power supply terminals of the analog section 6 and the digital section 7 in the IC process structure of the N-type board.

Next, the operation will be described. In FIG. 1, the ground terminal of the analog section 6 is disconnected from the ground by the modem switch section 11 by the off control from the microcomputer section 5 during standby. Therefore, even when the power supply voltage is applied to the digital section 7, no current flows through the substrate resistance of the modem section 4. Even if the modem switch section 11 is turned off, the digital section 4 is still operating, so the first meter interface section 22 and the second meter interface section 23 are operated.
A call request from the first meter 20 or the second meter via the terminal can also be detected.

Next, the operation at the time of communication will be described. When performing automatic meter reading of the meter 7, a no-ringing communication service is used. When the terminal network control unit 18 detects the reversal of the polarity of the telephone line 2 by the reversal detection unit 9, the terminal network control unit 18 notifies the microcomputer unit 5 of the inversion, and the microcomputer unit 5 enters an operating state. Microcomputer 5
Turns on the modem switch section 11 and puts the analog section 6 of the modem section 4 into an operating state. Upon receiving the no ringing call signal (NRS), the analog section 6 sends a response signal (ANS) to the telephone line 2. As a result, the center terminal 1 and the terminal network control device 18 enter a communication state. In the communication state, the received signal from the center terminal 1 is demodulated by the analog unit 6 of the modem unit 4, and when communicating with the first meter 20, the microcomputer unit 5 controls the digital unit 7 to change the transmission path. First meter interface unit 2
2 and the first meter interface unit 22 transmits the signal to the first meter 20. Conversely, meter 20
Transmits a signal, the data signal transmitted via the first meter interface unit 22 is modulated by the analog unit 6 and transmitted to the center terminal 1.

Next, when it is desired to communicate with the center terminal 1 from the first meter 20, the first meter 20 notifies the microcomputer unit 5 via the first meter interface unit 22 that the terminal call communication is to be performed. . Next, the microcomputer unit 5 detects the voltage state of the telephone line 2 by the line voltage detection unit 8 to detect whether the telephone 17 connected to the terminal network control device 18 is currently in use, and if not, the relay unit By controlling the driver unit 14, the relay 13 is driven by the power of the relay driving capacitor 15, and the connection between the telephone line 2 and the telephone 17 is disconnected. Then, the telephone line 2 is closed by the line terminating unit 3 and dialing is performed, and thereby communication with the center terminal 1 is performed.

After the communication, the relay 13 is driven again by controlling the relay driver 14 so that the telephone line 2 and the telephone
Connect with the side. After the end of the communication, the modem switch section 11 is turned off under the control of the microcomputer section 5, and the analog section 6 of the modem section 4 stops operating. The voltage drop of the battery 16 is detected by the microcomputer unit 5 controlling the battery voltage drop detection unit 10. If the battery voltage has dropped, the battery voltage drop detecting section 10 notifies the microcomputer section 5 of the drop.

(Embodiment 2) FIG. 2 is a block diagram of a terminal network control apparatus according to Embodiment 2 of the present invention.

The difference from the first embodiment is that the analog section 6 operates by receiving a reference voltage from the outside, and the modem reference power supply section 20 supplies a reference voltage based on the ground terminal of the analog section 6. And that The components having the same reference numerals as those in the first embodiment have the same structure, and the description will be omitted.

In FIG. 2, a center polling call from the center terminal 1 via the telephone line 2
When the microcomputer unit 5 is activated by a terminal call request from the second meter 21 or the second meter 21, the microcomputer unit 5 controls the modem switch unit 11 to turn on the analog unit 6 and activates the analog reference unit 6. Becomes active and supplies a reference voltage to the analog section 6. The ground terminal of the modem reference power supply unit 20 is connected to the modem switch unit 11 even if the current consumption of the analog unit 6 changes according to the operating state during communication, so that the collector-emitter voltage of the modem switch unit 11 changes. Since the ground potential of the analog unit 6 is the same as the ground terminal of the analog unit 6, the reference voltage and the ground of the analog unit 6 change in the same direction and the same size, so that the analog unit 6 is always constant with respect to the ground terminal of the analog unit 6. A reference voltage can be supplied.

[0017]

As described above, according to the present invention, the ground terminal of the analog section is connected and disconnected by the modem switch section, so that only the digital section consumes current during standby, so that the leakage current of the entire modem is reduced. It can be significantly reduced.

Since the ground terminal of the modem reference power supply, which should be connected to the ground, is the same as the ground terminal of the modem in the modem switch, the current flowing through the transistor constituting the modem switch changes and the collector changes. Even if the emitter voltage varies, the reference voltage of the modem reference power supply unit and the ground of the modem unit change in the same direction and the same magnitude, so that a highly accurate and stable reference voltage can be supplied to the modem unit. .

[Brief description of the drawings]

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

FIG. 2 is a block diagram of a terminal network control device according to a second embodiment of the present invention;

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

[Explanation of symbols]

 4 Modem section 6 Analog section 7 Digital section 11 Modem switch section 12 Modem reference power supply section

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshihiko Yasui 1006 Kazuma Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. A modem section comprising an analog section for modulating and demodulating transmission data and a digital section for controlling a digital signal, and a modem switch section for controlling connection / disconnection of a ground terminal and ground of the analog section. Terminal network controller. 2. The terminal network control device according to claim 1, further comprising a modem reference power supply unit for supplying a reference voltage based on a ground terminal of the analog unit.