JPH04122159A - Ring trip circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Concerning a ring trip circuit in a subscriber circuit of an exchange, a ring trip circuit in a subscriber circuit that sends DC superimposed signals of different polarities is configured without using circuits of different polarities. For the purpose of this, when sending out a ringing signal to a subscriber line, it is possible to send out both a positive voltage superimposed ringer output in which a positive DC voltage is superimposed on an AC signal voltage and a negative voltage superimposed ringer output in which a negative DC voltage is superimposed. In the subscriber circuit, between the signal tliaI line connected to the positive voltage superimposed ringer or the negative voltage superimposed ringer and the signal sending line connected to one line of the subscriber line, the A ring trip circuit for detecting the formation of a DC circuit is provided, and a diode bridge is provided in the ring trip circuit, and one of a pair of opposing terminals of the diode bridge is connected to the signal power supply line, and the other is connected to the signal transmission line. a signal current monitoring means that connects to the subscriber line, connects a resistor between another set of opposing terminals, and outputs a voltage proportional to the current flowing through the resistor from both ends of the resistor; The voltage output from the signal current monitoring means when a voltage superimposition ringer or a negative voltage superposition ringer is connected is input, and is input when only alternating current is flowing through the resistor of the signal current monitoring means. The device is configured to include a direct current detection means that does not send out an output based on a voltage, but sends out an output based on an input voltage when a direct current exceeding a preset value flows in addition to the alternating current.

(Industrial Field of Application) The present invention relates to a ring trip circuit in a subscriber circuit of an exchange.

When a subscriber receives a call, the exchange sends a paging signal to the subscriber's terminal, and the paging signal includes a positive or negative DC voltage superimposed on the AC signal voltage. As is well known, before a subscriber terminal responds, a bell rings or the like is performed using an AC signal voltage, and when a DC circuit is formed by the response, a DC current flows due to the superimposed DC voltage. In the exchange, the subscriber circuit detects this direct current, identifies the subscriber's response, and stops the ringing signal. A circuit that detects a response using this direct current and stops the ringing signal is called a ring trip circuit.

The polarity of the DC voltage superimposed on the AC signal voltage is usually determined to be either positive or negative depending on the exchange,
When multiple subscriber terminals are connected to one subscriber line, a positive DC voltage is applied when calling one subscriber, and a negative DC voltage is applied when calling the other subscriber. Some methods are used in which a superimposed paging signal is sent.

Conventionally, in a subscriber circuit that can send out both a positive voltage superimposed ringer in which a positive DC voltage is superimposed on an AC signal voltage and a negative voltage superimposed ringer in which a negative DC voltage is superimposed, a ring trip The circuit uses polarity-specific DC current detection circuits, but since two types of DC current detection circuits are used, the scale of the subscriber circuit increases, and the large number of subscriber circuits impairs economic efficiency. It's causing problems.

Therefore, in a subscriber circuit that uses both a positive voltage superposition ringer and a negative voltage superposition ringer, a ring trip circuit is required that does not require providing DC current detection circuits for each polarity.

[Conventional technology]

FIG. 3 is a block diagram of the prior art.

In FIG. 3, subscriber terminals 8 and 9 of two subscribers are connected to the subscriber line 2, and when calling the subscriber terminal 8, a positive DC voltage is superimposed on the AC signal voltage. When the voltage superimposition ringer 3 calls the subscriber terminal 9, it is assumed that it is necessary to send out the negative voltage superposition ringer 4 in which a negative DC voltage is superimposed on the AC signal voltage.

Now, when there is an incoming call to the subscriber terminal 8, the switch SW in the subscriber circuit 31 is controlled by a circuit (not shown).
are connected to the solid line side, and then switches SW, , SW2 are switched to the dotted line side. As a result, the positive voltage superimposed ringer 3 is sent out through the resistor RP, the switch SW3, and the switch sw2 to the negative line of the subscriber line 2, for example, the R (ring) line, and is sent through the subscriber terminal 8 and the subscriber terminal 9. subscriber line 2
Return to the other wire, for example the T (chip) wire, and switch S
A circuit is formed through W+ to the earth, and an alternating current flows through this circuit. In this case, the polarity of the superimposed DC voltage is detected by a circuit (not shown) of the subscriber terminal 8.9, and only the bell of the subscriber terminal 8 is a ringing signal, that is, the AC current from the positive voltage superimposed ringer 3 is detected. It makes a sound.

In this state, since an alternating current flows through the resistor RP, an alternating current potential difference of VPZ to VPI is generated across the resistor Rp, and the differential amplifier circuit 33. is input. Although the internal circuit of the differential amplifier circuit 33F is not shown, the potential VP3 at the output section increases as the difference between the two input voltages P2 and VFI increases. The above AC potential difference VP
2 VPI is smaller than when DC current flows through resistor Rp, and when AC voltage is input, the difference in potential between VF6 and ■ is reduced by a filter (not shown) provided at the input section. Since it is configured to be input to an internal operational amplifier (not shown), the AC potential difference VP
2 Differential amplifier circuit 33 when VFI is input. Output voltage VPI□. has a low value.

The above output voltage V F:l (AC) is the comparator 34
．． However, since the comparison voltage VFth is set higher than the output voltage V P3 (ACI), no output is sent from the comparator 34. In other words, ■ is at a normal potential (e.g. V, 4=4
), and the output terminal R of the ring trip circuit 32
No output is sent to the TP.

When the subscriber terminal 8 responds in the above state, a DC circuit (not shown) is formed in the subscriber terminal 8 by a known method, and a DC current flows from the positive voltage superimposition ringer 3 through the resistor RP. , the potential difference V across the resistor Rp
P□ to VFI are values in which the DC potential difference due to the DC voltage is superimposed on the AC potential difference due to the AC signal voltage, and are input to the differential amplifier circuit 33°. In addition, the DC voltage is applied to the differential amplifier circuit 33. Since it is not affected by the filter at the input section of the circuit, the voltage value is input to the internal operational amplifier without being reduced. Therefore, the output voltage VP from the differential amplifier circuit 33F
S(Ill:) has a larger value than the output voltage V F3 (AC) when only the AC potential difference is manually applied.

The output voltage V P3 (DC) is determined by the comparator 34. The comparison voltage v rth is the output voltage (2) when the subscriber terminal 8 responds. .

. Since it is set to a smaller value, comparator 3
4. An output (for example, VP4=O) is sent out. By sending out an output from the output terminal RT-P of the ring trip circuit 32, the subscriber circuit 31 performs a ring trip operation by a circuit (not shown), and the switches sw, s
W2 is restored to the solid line side and signal transmission is stopped.

An example of incoming calls to the subscriber terminal 8 has been described above, but in the case of the subscriber terminal 9, a signal is sent from the negative voltage superimposed ringer 4 by switching the switch SW=.

In this case, the potential difference between both ends of the resistor RM is ■, 42~■, 4
1 is input to the differential amplifier circuit 33.4, and its output ■. is compared with the comparison voltage ■M in comparators 34 and 4,
■If 1 is greater than the comparison voltage ■, 4, the output terminal RTP
The ring trip is performed by sending out an output to , but the details are the same as the operation by the positive voltage superimposed ringer 3, so the details will be omitted.

As described above, in the prior art, the differential amplifier circuit and the comparator are the positive voltage superimposing ringer 3 and the negative voltage superimposing ringer 4.
It is necessary to provide two sets for each. This is 1
If this is done using a pair of differential amplifier circuits and comparators, for example, the resistor R2 is provided so as to be common to the signal sending circuits of the positive voltage superimposing ringer 3 and the negative voltage superimposing ringer 4, and the potential difference VP2 and VPI between the two ends is set as a difference. The differential amplifier circuit 33. is input to the differential amplifier circuit 33p. is designed to input two potentials VP2 and ■□, and send out the output voltage VP3 when ■2□ is a higher potential than VFI, so the negative voltage superimposition ringer 4 is connected and the polarity is reversed. If so, no output will be sent on response.

In order to send out an output upon response when the polarity is reversed, when the negative voltage superimposition ringer 4 is connected, a resistor R is required.
The polarities of the potentials VFI and Vll at both ends of the differential amplifier circuit 33.7 are inverted. However, since both the DC voltage and the AC signal voltage of the DC voltage superimposed signal are high, a method of switching using a relay contact will be used. However, this method is not put to practical use because it requires a large amount of space and cost, including the control circuit.

For the above reasons, in the prior art, in the ring trip circuit of a subscriber circuit that uses both a positive voltage superimposed ringer and a negative voltage superimposed ringer, two sets of main circuits are provided, one for positive voltage and one for negative voltage, which impairs economic efficiency. This is the result.

[Problem to be solved by the invention]

In subscriber circuits that can send out both a positive voltage superimposition ringer in which a positive DC voltage is superimposed on an AC signal voltage and a negative voltage superimposition ringer in which a negative DC voltage is superimposed, conventional technology Since DC current detection circuits are used for each voltage polarity, the circuit scale of the subscriber circuit becomes large, resulting in a problem of loss of economic efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to configure a ring trip circuit in a subscriber circuit that sends DC superimposed signals of different polarities without using circuits of different polarities.

[Means to solve the problem] FIG. 1 is a basic configuration diagram of the present invention.

In the figure, ■ is a subscriber circuit of the exchange, 2 is a subscriber line, 3 is a positive voltage superimposition ringer that superimposes a positive DC voltage on an AC signal voltage, and 4 is a ringer that superimposes a negative DC voltage on an AC signal voltage. A negative voltage superimposing ringer, 5 is a signal power line connected to either the positive voltage superimposing ringer 3 or the negative voltage superimposing ringer 4 by switching, and 6 is connected to one line (R line) of the subscriber line 2. 7 is a ring trip circuit provided between the signal power supply line 5 and the signal transmission line 6 and detects the formation of a DC circuit in the subscriber line 2 when sending out a ringing signal; 8 is a ring trip circuit for the subscriber line 2; Connected subscriber terminals 9 are other subscriber terminals connected to the same subscriber line 2; 10 is provided in the ring trip circuit 7 and has a diode bridge 11 therein; One set of opposing terminals of 11 is connected to the signal power supply line 5, the other to the signal sending line 6, and a resistor 12 is connected between the other set of opposing terminals.
and a signal current monitoring means for outputting a voltage proportional to the current flowing through the resistor 12 from both ends of the resistor 12; 20 is connected to the subscriber line 2 to which the positive voltage superimposing ringer 3 or the negative voltage superimposing ringer 4 is connected; The voltage output from the signal current monitoring means 10 when the signal current monitoring means 10 , is a DC current detection means that outputs an output with an input voltage when a DC current of a preset value or more flows in addition to the AC current.

[Function] In FIG. 1, subscriber terminals 8 and 9 of two subscribers are connected to subscriber line 2, and when calling subscriber terminal 8, a positive DC voltage is added to the AC signal voltage. It is assumed that when calling the subscriber terminal 9, it is necessary to send out the negative voltage superimposed ringer 4, in which a negative DC voltage is superimposed on the AC signal voltage, using the superimposed positive voltage superimposed ringer 3.

Now, when there is an incoming call to the subscriber terminal 8, the switch SW3 in the subscriber circuit 1 is connected to the solid line side under the control of a circuit (not shown), and then the switches s W, , SW
! is switched to the dotted line side. As a result, the positive voltage superimposing ringer 3 becomes
, the signal transmission line 6 and the switch SWz to one line of the subscriber vA2, for example, the R (ring) line, and the signal is transmitted to the other line of the subscriber line 2, T
(chip) Returning to the wire, a circuit is formed that connects to the earth via the switch sw, and an alternating current flows through this circuit.

In this case, the polarity of the superimposed DC voltage is detected by a circuit (not shown) of the subscriber terminal 8.9, and only the bell of the subscriber terminal 8 is a ringing signal, that is, the AC current from the positive voltage superimposed ringer 3 is detected. It makes a sound.

In this state, since the full-wave rectified alternating current flows through the resistor 12, a pulsating voltage whose polarity is fixed in one direction is generated at both ends of the resistor 12, and the DC current detecting means 20
is input. Although the internal circuit of the DC current detection means 20 is not shown, it is designed to send an output when the voltage input from both ends of the resistor 12 is higher than a preset comparison voltage. However, since the comparison voltage is set higher than the input voltage when the AC current is full-wave rectified and input from both ends of the resistor 12, the DC current detection means 20 does not send out an output in the above state.

When the subscriber terminal 8 responds in the above state, a DC circuit is formed within the subscriber terminal 8 (not shown), and a DC current flows from the positive voltage superimposition ringer 3 to the same circuit as above, so that the resistor 12 The potential difference between both ends becomes a value in which the DC potential difference due to the DC current is superimposed on the voltage generated by the current obtained by full-wave rectification of the AC signal voltage, and is input to the DC current detection means 20. The comparison voltage is set so that if the DC current in this state is equal to or higher than a preset value, the voltage across the resistor 12 will be higher than the comparison voltage. sends output. That is, the DC current detection means 20 sends out an output in response to the response from the subscriber terminal 8, and thereby the subscriber circuit 1 performs a signal trip operation by a circuit not shown, and restores the switches s w1 and s w2 to the solid line side. and stop sending the signal.

As mentioned above, in FIG. 1, the signal current monitoring means 10
By fixing the direction of the current at the resistor 12
Only the absolute value of the voltage is output from both ends of the ring, so that the direct current detection means 20 can be used in common with either the positive voltage superimposition ringer 3 or the negative voltage superposition ringer 4.

〔Example〕

FIG. 2 is a circuit diagram of an embodiment of the present invention.

Throughout the figures, the same objects are indicated using the same symbols, and 21
22 is also a comparator, and OF2. .

OP2□ is an operational amplifier, D II-D 14 is a diode that constitutes the diode bridge 11, Dz+, D
z□ is the diode in the comparator 22, R1+ is the first
Resistor 12 and R21 to R27 in the figure are other resistors,
CZ+ is a capacitor.

In FIG. 2, the signal transmission conditions for the subscriber line 2 are the same as those in FIG. 1, and a case will be described in which there is an incoming call to the subscriber terminal 8.

When a call arrives at the subscriber terminal 8, the switch sw in the subscriber circuit 1 is connected to the solid line side under the control of a circuit not shown, and then the switches swl and swt are switched to the dotted line side. This causes the alternating current from the positive voltage superimposed ringer 3 to flow to the switch sw.

, signal power line 5, diode DI4-resistance RIl-diode D1□ or diode DI3=resistance R.

The signal is sent out to one line of the subscriber line 2, for example, the R (IJ song line) via the diode D0, the signal sending line 6, and the switch SWz, and is sent to the subscriber line 2 via the subscriber terminal 8 and the subscriber terminal 9.
It returns to the other line, the T (chip) line, and flows through the switch sw to the circuit that leads to the ground.

In the above state, the alternating current flows through the diode bridge 11
Since full-wave rectification is performed by the resistor R11, current flows only in the direction indicated by the arrow in the figure. This current generates a pulsating voltage across the resistor 12, but the potential ■1 at one end of the resistor R11 and the potential v2 at the other end are both higher when the signal power line 5 side is at a positive potential. Since the potential is higher than when the power line 5 side is at a negative potential, the potential V,, V2
The waveform is a waveform in which the peak value changes every half wave in addition to the pulsating flow due to full wave rectification. However, the potential ■ is higher than the potential ■2
, and V and -V2 always show a constant value.

These potentials V, V2 are input to the differential amplifier circuit 21, smoothed by a filter formed by the input resistors R1I, R24 and the capacitor CH+, and then passed through the respective resistors R22 and R2S to the operational amplifier OP.

is input. The output voltage (3) of the operational amplifier 0P2I changes according to the magnitude of the input voltage, that is, the potential difference V, -V2 between the potential VI and (2) according to the well-known function of operational amplifiers. When only the rectified current flows, the potential difference V, -V2 is small, so the operational amplifier O
P2. The output voltage ■3 is also small.

The output voltage (Vth) is input to the comparator 22 and compared with the comparison voltage (Vth).
Operational amplifier OP when only AC rectified current flows through +
Since the output voltage of z+ is set larger than ■3,
The operational amplifier OP2□ of the comparator 22 outputs a logic level high potential. A state in which a positive logic level potential is output from the operational amplifier OP z□ indicates a state in which a ring trip is not performed.

Next, when the subscriber terminal 8 responds, a DC circuit is formed in the subscriber terminal 8 (not shown), and the DC current due to the DC voltage of the positive voltage superimposition ringer 3 is passed through the switch SWz, the signal power line 5, the diode DI4, Resistor RI+, diode DI
2. Signal transmission line 6, subscriber line 2 via switch SWz
R line, subscriber terminal 8, T line of subscriber line 2, switch s
It flows through the circuit that leads to earth through w. At this time, the value of the alternating current also changes from before the response, but since the direct current is added to the alternating current, the current flowing through the resistor R1+ increases significantly compared to the case where only the alternating current flows before the response.

Therefore, the voltage input to the differential amplifier circuit 21, that is,
The potential difference V, -V2 between the potentials v1 and V2 becomes large, and the output voltage ■3 of the operational amplifier ○P2□ also becomes a large value. The voltage ■3 is compared with the comparison voltage ■ in the operational amplifier OP2□ of the comparator 22, but at this time V3>V.
Therefore, the output level of the operational amplifier OP2□ becomes a low potential of the logic level. Since the output of a low potential to the output terminal RTP of the comparator 22 means detection of a response from the subscriber terminal 8, the subscriber circuit 1 performs a signal trip operation by a circuit not shown, and switches the switches SW, , swz. Return to the solid line side and stop sending signals.

The ring trip operation for the subscriber terminal 8 has been explained above, but in the case of the subscriber terminal 9 using the negative voltage superimposed ringer 4, when the subscriber terminal 9 responds, a negative DC voltage flows to the diode bridge 11. The direction of the current is from the ground through the subscriber line 2 to the signal transmission line 6 and the diode D, 1.
, the resistor R0, the diode D13, and the signal power line 5 to the negative voltage superimposing ringer 4, but the direction of the current flowing to the resistor RI+ is the subscriber terminal 8 using the positive voltage superimposing ringer 3.
Since the direction is the same as in the case of , the operations in the differential amplifier circuit 21 and the comparator 22 are exactly the same as in the case of the subscriber terminal 8.

That is, in FIG. 2, since the differential amplifier circuit 21 and the comparator 22 perform the same operation regardless of whether the positive voltage superimposing ringer 3 or the negative voltage superimposing ringer 4 is used, these circuits are superimposed on the ringer. There is no need to provide two sets corresponding to the polarity of the DC voltage.

Although the present invention has been explained in detail with reference to FIG. 2 above, FIG. For example, in Fig. 2, the positive voltage superimposition ringer 3 and the negative voltage superposition ringer 4 are connected in series with the AC signal voltage and the DC voltage, but one end of the switch SW3 is connected to the ground. A positive or negative DC voltage is connected to the operating side contact of the switch 3W, which is connected to the direct AC signal voltage and connected to the ground in Fig. 2, by a switching contact instead of the ground. It is clear that the operation and effects of the present invention do not change even if the switches sw to SW3 are used as relay contacts in FIG. 2, but they are not limited to mechanical contacts such as relay contacts. It is.

The present invention does not exclude these variations.

〔Effect of the invention〕

As explained above, according to the present invention, either a positive voltage superimposed ringer in which a positive DC voltage is superimposed on an AC signal voltage or a negative voltage superimposed ringer in which a negative DC voltage is superimposed on an AC signal voltage is used as a ringing signal for a subscriber line. In subscriber circuits that can also send out DC voltages, it is possible to configure a ring trip circuit without using a circuit that operates depending on the polarity of the DC voltage to be sent out. There is an extremely large contribution to be made.

[Brief explanation of the drawing]

FIG. 1 is a basic block diagram of the present invention, FIG. 2 is a circuit diagram of an embodiment of the present invention, and FIG. 3 is a block diagram of a conventional technique. In the figure, 1 -----------・・----11-------------
---Subscriber circuit 2 ・--111...--1111-------Subscriber line 3-----
−−−−−−−−−−−−−− One positive voltage superimposed ringer 4−
−−−−−・−11−−−−−−−−−−−−−−−・
Negative voltage superimposed ringer 5−−−−−−−−−−−−・−=
−・−−11−−−−Signal power line 6−−−−−−−−
−−−−−−−−−−−−−−One signal sending line 7 −−−
−−−−−−−−−−−・・・−−−−−−111・
Ring trip circuit 8, 9 ---1--...
−11−−・−Subscriber terminal 10−−−−−1・−・−・
−・−・−・−−−1−−−Signal current monitoring means 1
1−・−−11−−−−−−−−−−−−−−−−−11−−Diode bridge 12−−111・−−−−−
−−−−−−−−−−1・−・−Resistance 20−−−−−−
-------------------------------------------------1.

Claims (1)

[Claims] A positive voltage superimposition ringer (3) that superimposes a positive DC voltage on an AC signal voltage when sending a ringing signal to a subscriber line (2).
In the subscriber circuit (1) capable of sending either a negative voltage superimposed ringer output in which a negative DC voltage is superimposed on the positive voltage superimposed ringer (3) or a negative voltage superimposed ringer (
4) and the signal power line (5) connected to the subscriber line (2).
) A ring trip circuit (7) is provided between the signal sending line (6) connected to one line (R line) of the subscriber line (2) for detecting the formation of a DC circuit in the subscriber line (2) when sending out a ringing signal. , and has a diode bridge (11) in the ring trip circuit (7), one of a pair of opposing terminals of the diode bridge (11) is connected to the signal power supply line (5), and the other is connected to the signal transmission line (5). A resistor (12) is connected between the other pair of opposing terminals, and a voltage proportional to the current flowing through the resistor (12) is applied to the resistor (12).
), and when the positive voltage superimposition ringer (3) or the negative voltage superimposition ringer (4) is connected to the subscriber line (2), the signal current monitoring means (10) outputs from both ends of the subscriber line (2). (10) Input the voltage output from
When only an alternating current is flowing through the resistor (12) of the signal current monitoring means (10), the input voltage does not send out an output, and in addition to the alternating current, a direct current exceeding a preset value is generated. It is equipped with a DC current detecting means (20) that outputs an output at the input voltage when the current flows, and when sending out either a positive voltage superimposed ringer or a negative voltage superimposed ringer to a subscriber line, the DC current of the subscriber line is A ring trip circuit characterized in that circuit formation can be detected by each pair of signal current monitoring means and direct current detection means.