JP3473125B2 - 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 network control device connected to an analog telephone line, and more particularly to a terminal network control device used for communication control between a meter reading meter and a center terminal in automatic meter reading or the like.

[0002]

2. Description of the Related Art In recent years, many telephones are composed of electronic circuits such as transistors and ICs. Recently, an operating power supply necessary for starting up this electronic telephone has been supplied only by electric power from a telephone line without using an external AC power supply or a battery.
However, line power is supplied to the speech circuit only when the handset of the telephone is lifted (off-hook). This is because the DC resistance of the telephone when viewed from the line is 1 MΩ when the handset is placed (on-hook state).
The line voltage must be 48
When V, only a current of 48 μA or less can be drawn from the line. Therefore, in order to use additional functions that require a relatively large amount of power, such as a speed dial memory and an answering machine function in the on-hook state, it is only possible to use an AC power supply or a battery.

In order to drive a 600Ω line transformer in a speech circuit to send a signal, for example, 0 dBm
In order to output a signal of (amplitude width of 2.2 V), a driving force sufficient to flow a current of about 3.7 mA is required by itself.

By the way, in the terminal network control device for automatic meter reading, it is necessary to constantly operate the storage circuit of the telephone number of the center and the time counting circuit for automatic calling. It is inconvenient to take AC power and battery power is used. Also, in order to reduce the battery replacement as much as possible, it is necessary to have a sufficient battery capacity.

As the communication of the terminal network control device, no-ringing communication is used for communication by center polling, in addition to call communication from the terminal in the off-hook state as in the above-mentioned telephone. When detecting a no-ringing call signal, a call signal detection circuit and the like operate simultaneously in a plurality of terminal network control devices connected in parallel to a telephone line. At this time, since the DC resistance seen from the line must be 4 kΩ or more according to the technical standard, for example, when the line voltage is 30 V, all the devices can draw only a current of about 7.5 mA or less from the line.

As a meter-reading data transmission device, Japanese Patent Laid-Open No. 63-63
As seen in Japanese Unexamined Patent Publication No. 180262, a method of taking in power from a telephone line with a DC resistance of 1 MΩ or more by using a DC / DC converter is considered. FIG. 5 shows a configuration example of the transmission device, 3 is a line terminating unit that connects the transmission device 1 to the telephone line 2, and 5 is a transmission / reception unit that is AC-connected to the telephone line 1 via a 600Ω line transformer 4. Detects an incoming signal from the telephone line 2 by an incoming call detection unit. An off-hook detection unit 7 detects whether the telephone 8 has raised the handset. A meter interface unit 9 transmits meter reading data from the meter 10 used as a terminal to the control unit 11. The control unit 11 uses a RAM or RO as a storage unit.
Each circuit is controlled by a microcomputer that has a timer circuit and has a built-in M and that operates according to a pre-installed program. Reference numeral 12 denotes a power supply unit, which is connected to the telephone line 2 to output a constant voltage and supply it to each circuit. A center terminal 13 is connected to the telephone line 2 and collects meter-reading data of the meter 10 via the device 1.

The operation of the meter reading data transmission device 1 will be described below with reference to FIG. The meter reading data obtained by the meter 10 is sent to the control unit 11 via the meter interface unit 9. The microcomputer of the control unit 11 activates the line terminating unit 3 when the timer notifies that the predetermined time has come. At this time,
The control unit 11 determines whether the incoming call detection unit 6 and the on-hook detection unit 7 are operating, and if it determines that one of them is operating, it suspends the activation of the line terminating unit 3 until the operation ends. Next, the telephone 8 is operated to dial a predetermined telephone number to connect to the center terminal 13. When the center terminal 13 is connected, the center terminal 1
Reference numeral 3 notifies the control unit 11 of a connection completion signal through the line terminating unit 3, the line transformer 4 and the transmitting / receiving unit 5. It suffices that the control unit 11 can send the meter-reading data from the transmission / reception unit 5 to the center terminal 13 via the telephone line 2 in response to the signal. However, in this embodiment, although the power supply from the telephone line is always used, it cannot be guaranteed that the device operates only by the power supply from the line, and when the power supply is insufficient, the battery or AC such as the external power supply unit 16 is used. It requires power supply from a power source.

[0008]

In the terminal network control device using the battery power source as in the conventional case, it is difficult to reduce the size and the cost is increased. In addition, if a system that constantly draws the same amount of power from the line requires more power during communication than during non-communication, it is not possible to operate a circuit that requires power only with the power supplied from the telephone line. Can not.

When the terminal network control device is connected to the telephone line, it is necessary to initialize the state of the control unit. However, when the control unit is composed of a circuit for clock operation such as a microcomputer, a relatively large current may be required to start the oscillation of the clock itself and perform the initialization operation. For this reason, it is very difficult to initialize the telephone line when it is connected to the telephone line only by making the input resistance to the telephone line very high and capturing a small amount of line current.

Further, in the case of performing the no-ringing communication only with the power from the line, in the case of the system for driving the 600Ω line transformer to send the signal as shown in FIG. It requires 7 mA and more power needs to be supplied from the telephone line to operate all circuits.

If the terminal network control device is operated only by the power from the line, the once connected telephone line is disconnected or the supply voltage of the telephone line is lowered, so that the device cannot be supplied with power. When it disappears, the call destination telephone number, call conditions, etc. that have been set once are deleted.

Further, when a call request is made from a terminal such as a meter to the call request unit, communication on the telephone line is not yet performed (in an on-hook state), so the electric power taken from the line is very small, In the communication between the call requesting unit and the control unit before a call is made between the terminal in which a large amount of current temporarily flows, the power supply voltage is lowered and normal communication cannot be performed.

Further, when electric power for operating each circuit is obtained from the line, a large current cannot be taken in from the line because of the limitation of the direct current resistance value seen from the line, so that the circuit consumes a large amount of current with the current as it is. Can not be operated.

In order to solve the above problems, it is a first object of the present invention to provide a terminal network control device that can operate only with electric power supplied from a telephone line.

A second object of the present invention is to provide a terminal network control device which surely initializes a control unit such as a microcomputer when a device is connected to a telephone line.

A third object of the present invention is to provide a terminal network control device which does not need to supply a large amount of line power for signal transmission.
The purpose of.

It is a fourth object of the present invention to provide a terminal network control device which retains the previous state and does not need to be reset even if a voltage drop occurs in the telephone line due to a momentary interruption or the like.

A fifth object of the present invention is to provide a terminal network control device for performing communication without lowering the power supply voltage when communicating with a terminal before communication using a telephone line.

A sixth object is to provide a terminal network control device capable of drawing a larger current in the device even if the current drawn from the telephone line is small.

[0020]

In order to achieve the above object , the present invention provides a line opening / closing unit for opening / closing a telephone line,
A line termination unit that matches the DC resistance and AC impedance with the telephone line via the circuit switching unit, and a transmission / reception that modulates the transmission signal and demodulates the reception signal and transmits / receives to / from the telephone line via the line termination unit. Section, a control section that controls ON / OFF of the line switching section and state control of the transmission / reception section, a call request section that notifies the control section of a call request from a terminal, and an incoming call from a telephone line. Of the incoming call, which is connected to the telephone line and has an input resistance of 1
A first constant voltage generator for supplying electric power to the incoming call requesting unit, the outgoing call requesting unit, and the controller by taking in power from the telephone line at MΩ or more to generate a constant voltage, and the circuit switching unit. A second constant voltage generator for supplying electric power from the telephone line to generate a constant voltage to supply power to the transmission / reception unit and the controller.
Initialize the device by connecting it to the telephone line.
Have a part, and connect to the telephone line to the first constant voltage generator
Input resistance is small until initialization is completed, and after initialization,
Equipped with a resistance switching unit that makes the input resistance value 1 MΩ or more
It

In order to achieve the second purpose, the telephone
Via the line opening and closing part that opens and closes the line, and the circuit opening and closing part
To adjust the DC resistance and AC impedance with the telephone line.
And the line termination section that performs transmission, modulation of the transmitted signal and recovery of the received signal.
Transmission and reception with the telephone line through the line termination section
And the on / off control of the line switching unit.
From the terminal and the control unit that controls the state of the transceiver unit
A call request unit for notifying the control unit of the call request of
Incoming call required to detect an incoming call from the line and notify the control unit
It is connected to the hunting department and the telephone line and has an input resistance of 1 MΩ or more.
The power from the talk line is taken in to generate a constant voltage and
Power is supplied to the call request unit, the call request unit, and the control unit.
Via the first constant voltage generating section for supplying power and the circuit opening / closing section
The power from the telephone line is taken in to generate a constant voltage and
Power is supplied to the line termination unit, the transmission / reception unit, and the control unit.
And a second constant voltage generator for supplying power, and the line termination unit is a telephone
Resistor unit that matches the DC resistance value seen from the line, and transmitter / receiver unit
The transmission signal output from the resistor and the line impedance
And a signal transmission unit that amplifies the signal according to the ratio
And a signal transmission section configured by .

[0022] In addition, in order to achieve the third object, control
Even if there is no power supply to the office, the stored contents will not be erased
A source that can read and write with the power supplied from the line
A storage unit that stores at least one of a called number and a calling condition
Equipped with .

In order to achieve the fourth object, the first
To the constant voltage generator or the second constant voltage generator of
The output voltage is controlled by a switching regulator
Use a step-down unit .

[0024]

The terminal network control device of the present invention has the first configuration,
When the terminal network controller is connected to the telephone line, the first constant voltage is generated.
Since the input resistance of the live part is small, a large amount of current flows and the control part
The initialization unit provided in the control unit is controlled by the supplied power.
Initialize the state of. When initialization is completed, the first constant voltage
Since the input resistance value of the generator is 1 MΩ or more, take it from the line.
Since the current that flows in is small, it will always be
Satisfies a resistance value of 1 MΩ or more when viewed from the technical standard line
be able to.

Further, according to the second configuration, the output from the transmitter is made.
In Rukoto enter a delivery signal to the signal transmitting unit, receiving unit
Even if the signal output gain from the
The signal is amplified by the ratio of the resistance part to the line impedance.
Output to the line, and the DC resistance value is matched by the resistance section.
Be done.

Also, with the third configuration, the telephone line is momentarily disconnected.
Even if such a situation occurs, the contents of the memory section should be erased.
Communication can be performed as soon as the power of the telephone line is restored.
it can.

Further, according to the fourth structure, the first constant voltage is generated.
Use a step-down switching regulator for raw parts
High power efficiency can be obtained by reducing the voltage to create the power supply voltage.
Is supplied to each circuit.
Because it is possible to capture and
It is possible to operate the terminal network controller by the electric current.
Become. Similarly, a step-down switch is added to the second constant voltage generator.
Obtain the power supply voltage by stepping down using an itching regulator
This makes it possible to send and receive control units and
Can drive the communication unit.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a terminal network control device according to a first embodiment of the present invention.

In FIG. 1, 101 is a terminal network control device of the present invention, 102 is a telephone line, and DC between the lines is 48V. A diode bridge 114 rectifies the voltage between the input terminals L1 and L2 from the telephone line 102, eliminates the line voltage polarity, and outputs it. Reference numeral 103 denotes a line terminating unit for matching the DC resistance and the AC impedance seen from the line. Reference numeral 115 denotes a line switching unit, which is composed of a transistor switch and connects the output of the diode bridge 114 and the line terminating unit 103. Reference numeral 105 denotes a transmission / reception unit, which is constituted by a modem or the like, modulates a digital signal and sends it to the telephone line 102, and demodulates a modulated signal received from the telephone line 102 into a digital signal. Reference numeral 106 denotes a polarity reversal detection unit that functions as an incoming call requesting unit from the telephone line 102 and detects reversal of voltage polarity of the telephone line 102. 109 is a meter interface unit,
It has a function of a call requesting unit from the meter 110 which is a terminal, notifies the signal from the meter 110 to the control unit 111, and performs signal matching for notifying the signal from the control unit 111 to the meter 110. A control unit 111 is a RAM for temporarily storing a timer, a telephone number to be called, a calling condition, an operating state, and the like
Also, a microcomputer having a ROM in which a program is written in advance is provided, and each circuit of the device 101 is controlled according to the program. 1
Reference numeral 12 is a first constant voltage generator, which is a diode bridge 11
4 is connected to the output of 4 and takes in power from the telephone line 102 with an input resistance of 2 MΩ to generate DC 5 V, and the polarity reversal detection unit 106, the meter interface unit 109, and the control unit 11 are connected.
1 to power. 116 is a second constant voltage generator,
Similar to the line terminating unit 103, it is connected to the telephone line 102 by the line opening / closing unit 115, generates DC5V, and supplies power to the line terminating unit 103, the transmitting / receiving unit 105, and the control unit 111.

Next, the operation of the terminal network control device will be described with reference to FIG. The terminal network control device 101 is the telephone line 10.
2, the absolute value of the voltage of the telephone line 102 is changed by the diode bridge 114 to the first constant voltage generator 1
12 inputs. Therefore, as long as it is connected to the telephone line 102, the DC5 output from the first constant voltage generator 112
The constant voltage of V is constantly supplied to the control unit 111, the polarity reversal detection unit 106, and the meter interface unit 109. Since the input voltage of the first constant voltage generator 112 is 48V, the input resistance value is 2MΩ, and the output voltage is 5V, a current of about 22 μA is taken from the telephone line 102.

When the call request signal is sent from the meter 110 to the control section 111 via the meter interface section 109, the control section 111 outputs an ON signal to the line switching section 115, so that the transistor of the line switching section 115 is turned on. When turned on, the voltage of the telephone line 102 becomes the second constant voltage generator 116.
Will join. The second constant voltage generator 116 supplies power to the controller 111, the transmitter / receiver 105, and the line terminating unit 103, the line terminating unit 103 performs line impedance matching in the calling communication state, and the controller 111 transmits and receives. 1
05 and the line terminating unit 103 are controlled to dial the call destination written in the RAM to establish a connection with the center terminal 113. After connection with the center terminal, communication such as communication between the control unit 111 and the center terminal 113 and notification of meter reading data from the meter 110 to the center terminal 113 is performed. When the scheduled time is reached by the built-in timer of the control unit 111, the microcomputer of the control unit 111 automatically calls the call destination written in the RAM and communicates with the center terminal 113 as described above. . The callee telephone number written in the RAM is stored in the center terminal 1 by the no ringing communication described below.
13 is notified to the control unit 111, and written in the RAM by the microcomputer of the control unit 111.

At the time of no ringing communication, the following operation is performed. If the polarity of the telephone line 102 is reversed, the polarity reversal detection unit 106 detects it and notifies the control unit 111. Since control unit 111 outputs an ON signal to line switching unit 115, the transistor of line switching unit 115 is turned on, and the voltage of telephone line 102 is applied to second constant voltage generating unit 116.
The second constant voltage generator 116 includes a controller 111 and a transceiver 1.
05 and the line terminating unit 103, the line terminating unit 103 performs line impedance matching in the NRS detection state. The first constant voltage generator 112 is connected to the controller 111.
And the second constant voltage generator 116 supplies the power supply current. NRS from the line is the line termination unit 1
It is detected by the transmitting / receiving unit 105 via 03. When the transmission / reception unit 105 detects the NRS, it sends the NR to the control unit 109.
Upon notifying the S detection, the control unit 111 controls the line terminating unit 103 to match the line impedance in the no ringing communication state. After the connection with the center, the call control unit 111 and the center terminal 113 communicate with each other to write the call destination telephone number in the RAM, set the call condition, and the like from the meter 110 after the connection with the center. Center terminal 11
Communication such as notification of the meter reading data to 3 is performed.

As described above, in the terminal network control device according to the first embodiment, the terminal network control device can be operated without an external power source simply by connecting to the telephone line, and more current is supplied during communication. Is supplied to the terminal network control device, the supply current does not run short.

FIG. 2 shows a terminal network controller according to the second embodiment of the present invention. In FIG. 2, reference numeral 201 denotes an input resistance changeover switch, which functions as a resistance changeover section as a switch for changing over the input resistance of the first constant voltage generation section 112, and has an input resistance of 2 MΩ for the regulator 202 for outputting a constant voltage. Switch 200 kΩ. A reset unit 203 resets the microcomputer 20 when the output voltage of the first constant voltage generator 112 in the control unit 111 changes from 0 V to 1.8 V, which is the voltage at which the microcomputer 204 can be reset.
Reset 4 The microcomputer 204 has a timer, a RAM for temporarily storing a telephone number to be called, a calling condition, an operating state, and the like, and a ROM in which a program is written in advance.

Next, the operation of the terminal network controller of FIG. 2 will be described. When the terminal network control device 101 is connected to the telephone line 102, the input resistance changeover switch 201 is on, and the input resistance value of the regulator 202 is approximately 200 k.
It is Ω. Therefore, the electric power drawn from the telephone line 102 is 10 times as large as that when the input resistance is 2 MΩ, and the output voltage of the first constant voltage generating unit 112 rises faster by that amount. When the output voltage of the first constant voltage generator 112 rises to 1.8V, the reset unit 203 detects the voltage and resets the microcomputer 204. When the reset is completed, the microcomputer 204 sets the input resistance changeover switch 2
01 is turned off and the input resistance value of the regulator 202 is set to 2M.
Set to Ω. Therefore, the DC resistance value for the telephone line 102 is 2 MΩ.

As described above, in the terminal network control device according to the second embodiment, the initialization of the microcomputer at the time of line connection can be performed reliably and at high speed, and the line impedance is extremely high after the initialization of the microcomputer. , Can fully meet the technical standards.

FIG. 3 shows a terminal network controller according to the third embodiment of the present invention. In FIG. 3, 301 is a transistor,
As a signal transmission unit, it outputs the signal from the transmission / reception unit 105 to the telephone line. Reference numeral 302 denotes a bias voltage unit that applies a base bias of the transistor 301. Reference numeral 303 denotes a resistor which is a resistor portion and has a resistance value R1 and is connected to the emitter of the transistor 301 to determine the emitter current.

Next, the operation of the terminal network control device will be described with reference to FIG. The bias voltage unit 302 applies the base bias of the transistor 301,
By determining the emitter voltage VE of 01, the telephone line 1
Since the current IL that flows through 02 is obtained by VE / R1 by the resistor 303, it is possible to match the DC resistance during communication with the telephone line 102. Also, 600Ω
By connecting the resistor R2 and the capacitor C1 between the collector of the transistor 301 and the ground, the AC impedance seen from the telephone line 102 is a standard value at the time of communication 60.
Matches to 0 ohms. The signal sent from the transmitter / receiver 105 is AC-coupled to the base of the transistor 301 through the capacitor C2 and is superimposed on the collector voltage. At this time, the amplitude of the transmitted signal can be determined by the ratio of the impedance on the collector side and the resistance R1. For example, resistor 3
When the resistance value R1 of 03 is set to 30Ω, the resistance on the collector side is considered to be parallel to R2 and 600Ω which is the impedance of the telephone line, so it becomes 300Ω, and the amplification factor becomes 10 times. Therefore, the amplification factor can be changed by changing the resistance R1. Further, a reception signal from the telephone line 102 is input to the transmission / reception unit 105 via the capacitor C3, and the transmission / reception unit 105 outputs the demodulated data to the control unit 11
Notify 1.

As described above, in the terminal network control apparatus according to the third embodiment, since the transmitting / receiving section does not need to directly send a signal of large amplitude, the power consumption of the transmitting / receiving section can be very small. It is sufficient that the constant voltage generating unit 2 takes in relatively little power from the telephone line.

FIG. 4 shows a terminal network control apparatus according to the fourth embodiment of the present invention. In FIG. 4, 401 is an EEPROM,
As a storage unit built in the control unit 111, a calling destination telephone number, a calling condition, a device state, and the like are written by a program and read out as necessary. Moreover, the written data is not erased even if power is not supplied. Four
A capacitor 02 is connected to the output of the first constant voltage generator 112 as a charger. 403 is the first DC /
In the DC converter, the step-down switching regulator is used as the step-down unit of the first constant voltage generating unit 112, which has an input resistance of 1 MΩ or more and outputs DC5V with extremely high power efficiency. 404 is the second DC / DC
In the converter, the step-down switching regulator is used as the step-down unit of the second constant voltage generation unit 116, and DC 5V is output with extremely high power efficiency.

Next, the operation of the terminal network control apparatus of the fourth embodiment will be described with reference to FIG. When the terminal network control unit 101 is connected to the telephone line 102, the diode bridge 114
DC / DC converter 403 whose line voltage is the first via
Is input to. Since the input resistance is 2 MΩ and the line voltage is 48 V, the power that can be taken in is 1.152 mW. Since the output voltage from the first DC / DC converter 403 is 5V, when the conversion efficiency is 100%, the maximum is about 230 μA.
Can be supplied to the control unit 111, the polarity reversal detection unit 106, and the meter interface unit 109.

Call communication from the meter is performed in the following procedure. When a call request signal is sent from the meter 110 to the meter interface unit 109, the diode of the photocoupler 404 is turned on / off, and the output to the control unit 111 is turned on / off to be notified. At this time, each time the output transistor of the photocoupler 404 is turned on, a current is supplied from the first constant voltage generator 112, and thus more power is required than when it is turned off. Therefore, the first constant voltage generator 1
The shortage of electric power is supplied from the output capacitor 402 of 12 to the meter interface unit 109, so that a current sufficient to turn on the output transistor can be supplied. After a call request is made from the meter 110 to the control unit 111 via the meter interface unit 109, the control unit 111 performs call communication in the same procedure as in the first embodiment.

In addition, since it is necessary to set the impedance seen from the telephone line 102 to 4 kΩ during the no ringing communication, the current cannot flow so much into the telephone line 102, and the current that can be taken into the second constant voltage generator 116 is 1 mA.
Then, even if the line voltage drops to 30V, the power that can be taken in is 30mW. Since the output voltage from the second DC / DC converter 404 is 5V, the conversion efficiency is 100.
%, The control unit 11 outputs an output current of about 6 mA at maximum.
1 to the line termination unit 103 and the transmission / reception unit 105. The output current from the second DC / DC converter 404 is also used when calling the terminal. Furthermore, the first
In the same manner as in the above embodiment, the calling destination telephone number and calling conditions set by the center terminal 113 at the time of no ringing communication are written into the EEPROM 401 which is a temporary storage unit by the microcomputer. Therefore, if the line voltage disappears due to a momentary interruption of the telephone line 102 and power is not supplied to the control unit 111, communication cannot be performed. However, when the line voltage returns, the call destination telephone number and the call condition are set. Communication with the center terminal 113 is performed by a call request from the meter 110 or an automatic call request by a timer without resetting from the center terminal 113.

As described above, in the terminal network control apparatus according to the fourth embodiment, it is not necessary to carry out communication for resetting the telephone number of the call destination even if the telephone line is momentarily cut off. Power can be supplied without lowering the power supply voltage even when the power consumption is increased during non-communication for data transmission of some parts, and more current can be supplied to each circuit than the current sent through the telephone line. Therefore, a relatively large current can be supplied to each circuit of the terminal network control device even when a large amount of current cannot flow through the telephone line as in no ringing communication.

Although the input DC resistance value of the first constant voltage generator 112 is set to 2 MΩ, a higher resistance value may be used if the terminal network control device 101 can operate with a smaller current during non-communication. . Similarly, although the input current of the second constant voltage generating unit 116 is set to 1 mA, if the current supplied to the control unit 111, the transmitting / receiving unit 105, and the line terminating unit 103 is smaller, if the communication is possible, a smaller current is supplied. All you have to do is pull.

[0046]

According to the first configuration, the terminal network control device is powered on.
When connected to the talk line, the input resistance of the first constant voltage generator is small.
Since a large amount of current flows, the power supplied to the control unit
The initialization unit provided in the control unit initializes the control unit.
Ensures reliable and high-speed initialization of the microcomputer when connecting the line
Can be performed, and after a certain time, the first constant voltage generator
Since the input resistance value is 1 MΩ or more, the power taken in from the line
The flow becomes less, and the technical standard value is always maintained during non-communication after this.
It is possible to satisfy the resistance value of 1 MΩ or more as seen from the line.
It

[Brief description of drawings]

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

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

FIG. 3 is a configuration diagram of a terminal network control device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a terminal network control device according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram of a conventional terminal network control device.

[Explanation of symbols]

101 terminal network control device 103 line termination unit 105 transmitter / receiver 106 polarity reversal detection unit (incoming call request unit) 109 Meter interface unit (call request unit) 110 meters (terminal) 111 control unit 112 First constant voltage generator 115 Line switch 116 Second constant voltage generator 201 Input resistance change switch (resistance change unit) 203 Reset unit (initialization unit) 301 transistor (signal transmission unit) 302 Bias voltage section 303 resistance 401 EEPROM (storage unit) 402 Capacitor (charging part) 403 First DC / DC converter (step-down unit) 404 Second DC / DC converter (step-down unit)

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) G08C 13/00-17/02 G08C 19/00-23/04 G08C 25/00-25/04 H03J 9/00-9 / 06 H04M 1/00 H04M 1/24-1/62 H04M 1/66-1/82 H04M 3/02-3/06 H04M 11/00-11/10 H04M 19/00-19/08 H04Q 9/00 -9/16

Claims (4)

(57) [Claims] 1. A line opening / closing unit for opening / closing a telephone line, a line terminating unit for matching a DC resistance and an AC impedance with the telephone line via the circuit opening / closing unit, a transmission signal modulation and a reception signal demodulation. A transmission / reception unit for transmitting / receiving to / from a telephone line via the line terminating unit, a control unit for on / off control of the line opening / closing unit and state control of the transmission / reception unit, and a call request from a terminal. A call request unit for notifying the control unit, a call request unit for detecting an incoming call from a telephone line and notifying the control unit, and power from the telephone line connected to the telephone line and having an input resistance of 1 MΩ or more. Power from the telephone line via the circuit opening / closing unit, and a first constant voltage generating unit for taking in a constant voltage to generate power and supplying power to the incoming call request unit, the outgoing call request unit, and the control unit. To generate a constant voltage And a second constant voltage generator for supplying electric power to said line-termination transceiver unit and the control unit,
When the control unit is connected to the telephone line, the device is initialized.
A telephone line is provided for the first constant voltage generation unit having an initialization unit for
Input resistance is small from the time of connection to the end of initialization
The resistance to make the input resistance value 1 MΩ or more after initialization.
A terminal network control device having a switching unit . 2. A line opening / closing unit for opening / closing a telephone line, and
DC resistance and AC connection with the telephone line through the circuit switch
Impedance of the transmission line and the line termination for impedance matching.
Key and demodulate the received signal, and transmit the signal through the line termination section.
The transmission / reception unit that performs transmission / reception with the talk line and the line switching unit
A control for performing on / off control and state control of the transmitter / receiver.
Control unit and a caller that sends a call request from the terminal to the control unit.
The call request unit and the control unit by detecting an incoming call from the telephone line
Incoming call request section that notifies to and the input resistance connected to the telephone line
Is a constant voltage by taking in the electric power from the telephone line at 1 MΩ or more.
To generate the incoming call request unit, the outgoing call request unit, and the
A first constant voltage generator for supplying electric power to the controller,
Electricity is taken in from the telephone line via the road opening and closing unit
Pressure to generate the line termination section, the transmission / reception section, and the
A second constant voltage generator for supplying electric power to the controller,
A resistor section and the line termination unit to align the DC resistance as seen from the telephone line, and a signal generating portion for sending the transmission signal output from the transceiver to the line is amplified by the ratio of the line impedance the resistance portion And a signal transmission section composed of
End end network controller having. 3. A memory for storing at least one of a called number and a calling condition which can be read and written by the power supplied from a telephone line without erasing the stored contents even if the control unit is not supplied with power. any serial <br/> mounting of the terminal network control apparatus according to claim 1 or 2 including a part. 4. A first constant voltage generator or the second claim 1-3 noise using a step-down unit in step-down switching regulator to a constant voltage generator for controlling the output voltage
Terminal network controller according or Re.