JPH1098546A - Terminal network controller - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a high-impedance state of a DC closing circuit without providing a ringing signal detection circuit, and to enable multiple connection. SOLUTION: In a terminal network control device 10, an AC transmission / reception circuit 12 and a DC loop connection circuit 15 are provided in parallel, so that the AC transmission / reception circuit 12 and the DC loop connection circuit 15 are hardly influenced by each other. The resistance of the DC loop circuit can be made high impedance without distortion of the AC signal when the no ringing selection signal is received, and the high impedance state can be maintained only when the no ringing selection signal is detected (during monitoring). Multiple connections can be made without opening the line.

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, and more particularly, to a terminal network controller capable of multiple connections.

[0002]

2. Description of the Related Art FIG. 2 shows a schematic configuration diagram of a conventional terminal network control device. The terminal network control device 50 is roughly divided into a 16 Hz detection circuit 51 that detects a call signal (frequency 16 Hz) input from the telephone line L and outputs a 16 Hz detection signal S16, and a polarity inversion of the telephone line during no ringing communication. , And a polarity inversion detection circuit 52 that outputs a polarity inversion detection signal SRV, a first input terminal TIN1, and a second input terminal TIN2.
A diode bridge circuit 53 having a first output terminal TOUT1 and a second output terminal TOUT2, and switching a current flow path based on a voltage relationship between the first input terminal TIN1 and the second input terminal TIN2; and a first input terminal TIN1. -2nd input terminal TIN2
A dial pulse generating circuit 54 for generating a dial pulse signal and outputting the dial pulse signal via the telephone line L, and a first input terminal TIN1 and a second input terminal TIN2,
No-ringing transmission / reception circuit 55 for receiving no-ringing communication and no-ringing selection signal (hereinafter, referred to as NRS signal) in a predetermined AC impedance state.
And a first primary coil C11 and a second primary coil C12
And a secondary coil C20, a first primary coil C1
One ends of the first and second primary side coils C12 are connected to the first output terminal T.
A transformer 56 having an AC impedance of 600 [Ω] commonly connected to OUT1, a hybrid circuit 57 connected to the secondary coil C2 of the transformer 56 for performing 2-wire 4-wire conversion, and connected to the hybrid circuit 57 And
A modem 58 for modulating / demodulating data and a controller 59 for controlling the entire terminal network control device 50 are provided.

The dial pulse generating circuit 54 includes a first transistor switch TSW11 having an emitter terminal connected to a second output terminal TOUT2, and a first transistor switch TSW.
One end is connected to the collector terminal of W11, the other end is connected to the first primary coil, and the collector terminal is connected to the base terminal of the transistor switch TSW11 via a resistor, and the emitter terminal is connected to the first terminal. And a first photocoupler PC1 having a first phototransistor PT1 connected to the output terminal TOUT1 and being turned on / off based on a first control signal CPC10 of the controller 59.

The no-ringing transmission / reception circuit 55 includes a second transistor switch TSW12 having an emitter terminal connected to a second output terminal TOUT2, and a transistor switch SW12.
Switch SW11 having one end connected to the collector terminal of the first switch SW11
And a second resistor R connected to the other end of the first switch SW11.
12, a capacitor CC connected in series to the second resistor R12, one end of which is connected to the second primary coil of the transformer, and one end connected to the collector terminal of the second transistor switch TSW12, and the other end connected to the second resistor R12. A second switch SW12 connected to the intermediate connection point between R12 and the capacitor CC, a collector terminal connected to the base terminal of the second transistor switch TSW12 via a resistor, and an emitter terminal connected to the first output terminal TOUT1. Two phototransistors PT2, and are turned on / OF based on a second control signal of the controller.
F2, a second photocoupler PC2.

Next, the operation will be described. At the time of terminal call At the time of terminal call, if the telephone line L is a dial line, the controller sends the first control signal CPC10 to the first control signal CPC10.
By controlling the photocoupler PC1, the first phototransistor PT1 is turned on and the first transistor switch TSW11 is turned on.
Is turned on to close the DC loop.

Then, similarly, on / off of the first transistor switch TSW11 is controlled by the first control signal CPC10 to generate a dial pulse, which is output to the telephone line L via the diode bridge 53. If the telephone line L is a push button line, the first transistor switch TSW11 is kept in the ON state, and the modem 58 is turned on.
Generates a push button signal (PB signal) in an AC impedance state of 600 [Ω]
7. A PB signal is transmitted through a transformer 56 of 600 [Ω].

Then, the modem 58 transmits and receives signals via the hybrid circuit 57 and the transformer 56 of 600 [Ω]. Upon detecting the polarity inversion of the telephone line, the polarity inversion detection circuit 52 outputs the polarity inversion detection signal SRV to the controller 59 during the no ringing communication .

As a result, the controller 59 determines that the no-ringing communication has been started, and the second control signal CPC
20 controls the second photocoupler PC2, turns on the second phototransistor PT2, turns on the second transistor switch TSW12, and controls the control signal SS.
By turning on the first switch SW11 by W11, the DC loop is half-closed and the reception of the NRS signal (no ringing selection signal) is waited.

When receiving the NRS signal, the controller 59 sends the first switch SW by the control signal SSW11.
11 is turned off, the second switch SW12 is turned on by the control signal SSW12, and the AC impedance is set to 600 [Ω].

Thus, the modem 58 and the hybrid circuit 57 are connected to the AC impedance 60 via the transformer 56.
No ringing communication is performed in the state of 0 [Ω].

[0011]

In the above conventional terminal network control device, the discharge path of the capacitor only passes through the diode bridge 53 and the second transistor switch TSW12. Therefore, the capacitor does not discharge the charge to the telephone line L side, and the capacitor and the resistor R (= R1 + R2) have a time constant τ = C × R. The signal must be set to a level that does not distort the signal, and cannot be set to a very high resistance value.

Therefore, in order to perform a multiple connection, etc.
There is a problem that it is necessary to provide a function of detecting the call signal by the 6 Hz detection circuit 51 and opening the telephone line L. SUMMARY OF THE INVENTION An object of the present invention is to provide a terminal network control device that can secure a high impedance state of a DC closed circuit without providing a call signal detection circuit (16 Hz detection circuit) and can perform multiple connection.

[0013]

According to a first aspect of the present invention, there is provided a terminal network control device having a no-ringing communication function, comprising detecting a polarity inversion of a telephone line during no-ringing communication and detecting a polarity inversion. A polarity reversal detection circuit that outputs a detection signal, and is connected to the telephone line based on a first connection control signal to close a DC loop circuit when a terminal call is made and to connect the DC loop circuit when a no ringing communication is performed; A DC loop closing circuit for semi-closing in a high impedance state equal to or higher than a value, and having a predetermined AC impedance connected in parallel to the DC loop closing circuit based on a second connection control signal, An AC transmitting and receiving circuit for transmitting and receiving, and based on the polarity inversion detection signal, or detecting a terminal calling state and A connection control signal and control means for outputting the second connection control signal is configured with a.

According to the first aspect of the present invention, in the terminal network control device having a no-ringing communication function, the polarity inversion detecting circuit detects the inversion of the telephone line during the no-ringing communication and controls the polarity inversion detection signal. Output to On the other hand, the control means outputs the first connection control signal to the DC loop closing circuit and outputs the second connection control signal to the AC transmission / reception circuit based on the polarity reversal detection signal or detecting the terminal calling state. .

As a result, at the time of calling the terminal, the DC loop closing circuit is connected to the telephone line based on the first connection control signal, and closes the DC loop circuit. A terminal call will be made.
Further, at the time of no ringing communication, the DC loop closing circuit half-closes the DC loop circuit in a high impedance state equal to or higher than a predetermined value, and the AC transmitting / receiving circuit executes the DC loop closing circuit based on the second connection control signal. Connected in parallel.

Thus, the AC transmitting and receiving circuit transmits and receives an AC signal (no ringing communication) in a predetermined AC impedance state. The invention according to claim 2 is the terminal network control device according to claim 1, wherein the DC loop closing circuit has a DC loop resistance connected in parallel to the telephone line, and a resistance value of the DC loop resistance. Is set to have a resistance value for maintaining a predetermined high impedance state required when a no ringing selection signal is received.

According to the second aspect of the present invention, in addition to the operation of the first aspect, the resistance value of the DC loop resistance of the DC loop closing circuit is a predetermined high impedance required at the time of receiving the no ringing selection signal. Since the resistance value is used to maintain the state, there is no need to open the line when a (16 Hz) ringing signal is received.

According to a third aspect of the present invention, in the terminal network control device of the first or second aspect, the AC transmission / reception circuit includes a capacitor and a third connection control signal constituting the second connection control signal. First connection means for connecting the capacitor to the telephone line via a resistor when receiving a no ringing selection signal based on the first connection control signal, and connecting the capacitor during no ringing communication based on a fourth connection control signal constituting the second connection control signal. And second connection means for connecting to a telephone line.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect, the first connection means of the AC transmission / reception circuit selects no ringing based on a third connection control signal. When receiving a signal, connect the capacitor to the telephone line via a resistor. The second connection means connects the capacitor to the telephone line during the no-ringing communication based on the fourth connection control signal.

[0020]

Preferred embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows a schematic configuration diagram of a terminal network control device. The terminal network control device 10 is roughly divided into a polarity inversion detection circuit 11 that detects the polarity inversion of the telephone line L during no-ringing communication and outputs a polarity inversion detection signal SRV, and an AC transmission and reception circuit 12 that transmits and receives an AC signal. ,
A hybrid circuit 13 connected to the AC transmitting and receiving circuit 12 for performing 2-wire to 4-wire conversion; a modem 14 connected to the hybrid circuit 13 for performing modulation / demodulation of data; and a DC for closing or semi-closing a DC loop. It comprises a loop closing circuit 15 and a controller 16 for controlling the entire terminal network control device 10.

The AC transmission / reception circuit 12 has a first relay circuit 17 having one end connected to a telephone line L1 constituting the telephone line L.
A resistor R1 (for example, 2 kΩ or more) connected in series to the other end of the first relay circuit 17;
7 and a second relay circuit 18 connected in parallel with the resistor R1.
And a capacitor C having one end connected to a common connection point between the resistor R1 and the second relay circuit 18, and the other end of the capacitor C connected to one end and the other end forming a telephone line L.
2 and a transformer 21 having an alternating-current impedance of 600 [Ω] having a primary coil C1 connected to the hybrid circuit 13 and a secondary coil C2 connected at both ends to the hybrid circuit 13.

The DC loop closing circuit 15 has a first input terminal TIN1, a second input terminal TIN2, a first output terminal TOUT1, and a second output terminal TOUT2.
A diode bridge circuit 19 for switching a current flow path based on a voltage relationship between input terminals TIN2, and a second output terminal TOU
Transistor switch T with emitter terminal connected to T2
SW, a constant current supply circuit 20 having an input terminal connected to the collector terminal of the transistor switch TSW and supplying a constant current; a first switch SW1 having an output terminal connected to one end of the constant current supply circuit 20; A resistor RL1 (for example, 50 to 300 [Ω]) connected in series to the switch SW1 and the other end connected to the first output terminal TOUT1, a common connection between the output terminal of the interruption current supply circuit 20 and the first switch SW1. A second switch SW2 having one end connected to a point;
A resistor RL2 connected in series to the switch SW2 and the other end connected to the first output terminal TOUT1 (for example, at least
Ω]. More specifically, the controller 16 has a phototransistor PT whose collector terminal is connected to the base terminal of the transistor switch TSW via a resistor, and whose emitter terminal is connected to the first output terminal TOUT1. And a photocoupler PC that is turned on / off based on the control signal CPC.

In this case, since the resistance R1 is not affected by the resistances RL1 and RL2, which are the DC loop resistances of the DC loop closing circuit 15, the resistance R1 can be set to a high resistance value. is there. The resistance RL2
Also, since it is not affected by the AC transmitting / receiving circuit 12, it is possible to set a higher resistance value as compared with the conventional example.

Next, the operation will be described. At the time of terminal call When the terminal call is made, if the telephone line L is a dial line, the controller 16 controls the photocoupler PC by the control signal CPC, turns on the phototransistor PT, and turns on the transistor switch TSW. At the same time, the first switch SW1 is activated by the first control signal CSW1.
Is turned on to close the DC loop.

As a result, the telephone lines L1 and L2 are
Diode bridge circuit 19 → transistor switch T
SW → constant current circuit 20 → first switch SW1 → first resistor R1 → diode bridge circuit 19 Thereafter, the controller 16 outputs the control signal CPC
Thus, on / off of the transistor switch TSW is controlled to generate a dial pulse, which is output to the telephone line L via the diode bridge circuit 19.

When the telephone line L is a push-button line, the transistor switch TSW is kept on, and the controller 16 outputs the first relay control signal CRL1 to turn on the first relay circuit 17. As a state, the resistor R1 and the capacitor C are connected to the transformer 2
1 in series with the primary coil C1 to generate a push button signal (PB signal) in the modem 13 in an AC impedance state of 600 [Ω].
A PB signal is transmitted through a transformer 21 of 2,600 [Ω].

Thereafter, the modem 58 transmits and receives signals via the hybrid circuit 12 and the transformer 21 of 600 [Ω]. As a result, since the discharge current of the capacitor C flows to the telephone line L (the telephone lines L1 and L2), it is not affected by the state of the DC loop closing circuit 15. Upon detecting the polarity inversion of the telephone line L, the polarity inversion detection circuit 11 outputs a polarity inversion detection signal SRV to the controller 16 during no ringing communication .

As a result, the controller 16 determines that the no ringing communication has been started, turns on the transistor switch TSW by the control signal CPC, turns on the first switch SW2 by the second control signal CSW2, and sets a high resistance value (for example, The DC loop is half-closed using a second resistor R2 having a resistance of 4 kΩ or more.

Then, the first relay circuit 17 is turned on by the first relay control signal CRL1 and is set to a high impedance state of 2 [kΩ] (resistance value of the resistor R1) or more.
Wait for the reception of the RS signal. Thereafter, the controller 16
When the RS signal is detected, the first relay circuit 17 is turned off by the first relay control signal CRL1, the second relay circuit 18 is turned on by the second relay control signal CRL2, and the modem 14 is set to an AC impedance of 600 [Ω].
To perform no-ringing communication.

According to the present embodiment as described above,
Since the discharge current of the capacitor C flows to the telephone line L side,
Because it is not affected by the DC loop closing circuit 15 (DC loop circuit), even if the DC loop resistance RL2 is set to a high resistance, N
No distortion occurs in the AC signal when the RS signal is received.

Therefore, it is not necessary to open the line even when the 16 Hz signal which is a calling signal is detected, and the high impedance state can be maintained only in the detection state (monitoring state) of the NRS signal. Becomes possible. Further, there is no need to provide a 16 Hz detection circuit for opening the line, and the circuit configuration can be simplified.

[0032]

According to the first aspect of the present invention, in the terminal network control device having the no ringing communication function, the polarity inversion detection circuit detects the polarity inversion of the telephone line during the no ringing communication and generates the polarity inversion detection signal. The control means outputs the first connection control signal to the DC loop closing circuit based on the polarity inversion detection signal or detects the terminal calling state, and transmits and receives the second connection control signal to the AC loop. Output to the circuit.

As a result, at the time of calling a terminal, the DC loop closing circuit is connected to the telephone line based on the first connection control signal to close the DC loop circuit, and the terminal network control device transmits the terminal call. Make a call. Further, at the time of no ringing communication, the DC loop closing circuit half-closes the DC loop circuit in a high impedance state equal to or higher than a predetermined value, and the AC transmitting / receiving circuit executes the DC loop closing circuit based on the second connection control signal. Are connected in parallel to each other, and transmit and receive an AC signal (no ringing communication) in a predetermined AC impedance state.

As described above, since the AC transmitting / receiving circuit and the DC loop closing circuit are provided in parallel, the AC transmitting / receiving circuit and the DC loop closing circuit are hardly affected by each other, and the AC signal is not affected when the no ringing selection signal is received. The resistance of the DC loop circuit can be made high without causing distortion in the circuit, and multiple connections can be made.

According to the second aspect of the present invention, in addition to the operation of the first aspect, the resistance value of the DC loop resistance of the DC loop closing circuit is determined by the value of the calling signal input via the telephone line. Since the resistance value is set to maintain a predetermined high impedance state without opening the line at the time of reception, it is not necessary to open the line at the time of receiving a (16 Hz) paging signal, so there is no need to provide a line opening function. Since the high impedance state can be maintained only when the no-ringing selection signal is detected (monitoring), multiple connections can be made.

According to the third aspect of the present invention, in addition to the operation of the first or second aspect, the first connection means of the AC transmission / reception circuit selects no ringing based on a third connection control signal. The capacitor is connected to the telephone line via a resistor when receiving a signal, and the second connection means connects the capacitor to the telephone line during no-ringing communication based on the fourth connection control signal, so that the discharge current of the capacitor flows to the telephone line side. As a result, the resistance value of the DC loop circuit can be made higher without being affected by the DC loop circuit.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a terminal network control device.

FIG. 2 is a schematic configuration diagram of a conventional terminal network control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Terminal network control device 11 Polarity inversion detection circuit 12 AC transmission / reception circuit 13 Hybrid circuit 14 Modem 15 DC loop closing circuit 16 Controller 17 First relay circuit 18 Second relay circuit 19 Diode bridge circuit 20 Constant current supply circuit 21 Transformer C capacitor C1 Primary coil C2 Secondary coil CPC control signal L1 Telephone line L2 Telephone line L Telephone line PT Phototransistor PC Photocoupler R1 Resistance RL1 Resistance RL2 Resistance SRV Polarity inversion detection signal SW1 First switch SW2 Second switch TIN1 First input Terminal TIN2 Second input terminal TOUT1 First output terminal TOUT2 Second output terminal TSW Transistor switch

Claims (3)

[Claims] 1. A terminal network control device having a no ringing communication function, comprising: a polarity inversion detection circuit that detects a polarity inversion of a telephone line during a no ringing communication and outputs a polarity inversion detection signal; Connected to the telephone line,
A DC loop closing circuit that closes the DC loop circuit at the time of calling a terminal and half-closes the DC loop circuit at a high impedance state equal to or higher than a predetermined value at the time of no ringing communication; An AC transmitting and receiving circuit connected in parallel to the DC loop closing circuit and having a predetermined AC impedance, for transmitting and receiving an AC signal, and based on the polarity inversion detection signal, or detecting a terminal calling state. Control means for outputting the first connection control signal and the second connection control signal, a terminal network control device. 2. The terminal network control device according to claim 1, wherein the DC loop closing circuit has a DC loop resistance connected in parallel to the telephone line, and the resistance value of the DC loop resistance is a non-ringing selection. A terminal network control device having a resistance value for maintaining a predetermined high impedance state required when receiving a signal. 3. The terminal network control device according to claim 1, wherein the AC transmission / reception circuit is configured to perform a terminal call based on a capacitor and a third connection control signal constituting the second connection control signal. First connection means for connecting the capacitor to the telephone line via a resistor when a no ringing selection signal is received; and connecting the capacitor to the telephone during no ringing communication based on a fourth connection control signal constituting the second connection control signal. A terminal network control device, comprising: second connection means for connecting to a line.