JPH0595573A - Ringer detection/polarity inversion detection circuit - Google Patents

Abstract

PURPOSE:To provide the ringer detection/polarity inversion detection circuit which can increase the detection level of ringer and can decrease the detection level of polarity inversion. CONSTITUTION:This ringer detection/polarity inversion detection circuit for detecting the ringer signal of an AC from a trunk line and the trunk line polarity inversion signal of a DC while being connected to two trunk lines is equipped with detectors P1 and P2 mutually inversely parallelly connecting the two pairs of detectors for detecting the signals by operating when an impressed voltage is turned to a forward voltage while having the directivity of electrification, first level adjusting means serially connecting a first resistor R2 for detected level adjustment and a capacitor C for passing an AC component, and second level adjusting means serially connecting a second resistor R3 for detected level adjustment and a directional element D to pass the trunk line polarity inverting signal so as to be parallelly connected to the first level adjusting means, and the detectors are connected through the parallel circuit of the first and second level adjusting means to the trunk lines.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a trunk line trunk circuit which is an interface for connecting to a central office line in an electronic exchange, and particularly to a ringer capable of optimally adjusting a detection level according to a signal system. The present invention relates to a detection / polarity inversion detection circuit.

[0002]

2. Description of the Related Art In a private branch exchange (electronic exchange), the central point of control is performed by software by a microprocessor (CPU), and the intelligentness is becoming higher and higher. An example of a general configuration of such an exchange is shown in FIG.
Shown in.

In FIG. 3, reference numeral 10 is a speech path switch for performing an exchange operation between an extension line, an outside line and an extension line. Reference numeral 11 denotes a central control unit, which is a call path switch 10
It plays a central role in controlling the entire exchange including the above. The central control unit 11 uses a processor (CPU) as a control center, and executes these control by executing a control program.

Reference numeral 12 denotes a storage unit, which is composed of a ROM (Read Only Memory) and a RAM (Random Access Memory), and holds various tables as well as a control program and a working area. Used for. The control program and data are stored in the RAM, and the initialization program and the initial program loader are stored in the ROM so that the control content and service functions can be changed. Uses the data read function of the initial program loader to externally load programs and data.

Reference numerals 20a to 20n are line circuits which are interfaces for connecting the speech path switch 10 and the extension telephones, and 21a to 21n are extension telephones connected to the speech path switch 10.

The extension telephones are connected to the speech path switch 10 via the corresponding line circuits 20a to 20n. 13 is a signal generator for generating various tone signals,
Reference numeral 14 is a maintenance terminal (maintenance terminal). The maintenance terminal 14 has a keyboard and a display, and is connected to the central control unit 11 via an interface (not shown). By operating the keyboard, commands and data can be exchanged with the central control unit 11. Reference numeral 15 is a reception board, and the reception board 15 is connected to the central control unit 11 and the communication path switch 10 via a reception board interface 16.

In the present electronic exchange system, the speech path switch 10 is controlled by the central control unit 11 and uses a time slot assigned by time division to pass signals such as voices between each office line and each extension and each extension. By doing, the exchange operation is performed, the call path is secured, and the call is made possible. The central control section 11 exchanges information with various services such as exchange control, designated time call registration control from the extension telephone, designated time call execution control and maintenance terminal 14, read / write control for the storage section 12, etc. In addition, it has a function of performing various controls.

Reference numerals 31a to 31n are trunk circuits for interfacing with the office line (outside line) accommodated in the speech path switch 10. The trunk circuits 31a to 31n are direct currents associated with outgoing and incoming calls to the office line. It is possible to detect the polarity reversal and the end of call. In such a configuration, when a call is made from the extension, the central control unit 11 detects this via the line circuit connected to the extension, and when the dial information from the extension is received, the dial information is received. From an internal line to an external line, and if it is to an internal line, if it is an internal line, check whether the extension at the destination is empty or not. A ringer ringing signal generated by the signal generator 13 is given through the central control unit 11 to ring the destination extension terminal.

When the extension responds, the central control unit 11 detects this and enables the call extension and the call extension via the call path switch 10. When the extension during a call is on-hook, the central control unit 11 detects the on-hook via the line circuit and controls the end of the call.

Further, in the case of making a call from an extension line to an outside line, the central control unit 11 searches for an empty trunk circuit, calls the station line through the empty trunk circuit, sends dial information, and the station side sends the dial information. The central control unit 11 enables a call between the calling extension and the office line via the call path switch 10 when the other party responds to the call based on the call.

An incoming call from an outside line (station line) is detected by the central control unit 11 via a trunk circuit to which the station line is connected, and in a system employing the representative system, the reception board 15 and the representative system are used. When the reception desk 15 or the extension of the representative answers, the central control unit 11 determines that the call path switch 1
When both parties are allowed to talk via 0 and a transfer operation is performed from the reception board 15 or the like, the central control unit 11 temporarily puts the incoming call extension on hold, connects it to the transfer destination extension, and after the transfer destination extension answers, the reception board When a predetermined operation is performed from 15 or the like, the hold outside line and the transfer destination extension are connected via the call path switch 10 to enable the call. As described above, the trunk circuit for connecting the office line in the electronic exchange for private branch exchange has conventionally been configured as shown in FIG.

That is, FIG. 4 is a circuit diagram showing a station line trunk circuit. In the figure, 40 is a station side, and 31 is a station line trunk of an electronic exchange, that is, a private branch exchange side that interfaces with a station line. It is a station line trunk circuit provided.

The office line trunk circuit 31 is a circuit for sending and receiving control signals for calling, answering, restoring, and the like, and also for sending and receiving voice signals. An AC signal is sent and received to and from a two-line office line drawn from a central office switch. The primary side of the transformer 36 is connected, and a capacitor 35 is further connected in series to the primary side of the transformer 36.

In the figure, the two-line local lines are Tip and Ri.
The primary side of the transformer 36 is connected to the Tip terminal connection side line of the office line, and the other end is connected to the Ring terminal connection line side of the station line through the capacitor 35. Then, the ringer detection / polarity inversion is made up of a ringer detection circuit 32a for detecting a ringer signal from the station and a polarity inversion detection circuit 32b for detecting a polarity inversion signal of the station across the station line of the two-line configuration. The detection circuit 32 is connected, and the T of the station line on the primary side of the transformer 36 is further connected.
A relay 33 is connected in series to the ip terminal connection side line.

The relay 33 is a relay that closes the DC loop at the time of answering an incoming call or making a call, interrupts the DC loop at the time of sending a dial pulse, and opens the DC loop at the time of restoration. At the latter stage side, that is, at the transformer 36 connection side of the relay 33, the Tip and Ring of the station line
The DC circuit 34 is connected across the line and. The DC circuit 34 is a circuit for forming a DC loop with respect to the power supply from the station.

Further, the secondary side of the transformer 35 is connected to a hybrid circuit 37 which performs 2-line to 4-line conversion and encoding / decoding of a voice signal, and inputs / outputs a voice signal.

FIG. 5 is a circuit diagram showing a configuration of a ringer detection / polarity inversion detection circuit 32 in a conventional office line trunk circuit. In the figure, P1 and P2 are photocouplers, and the primary sides of these photocouplers P1 and P2 are connected in parallel in opposite directions. The anode of the photocoupler P1 and the cathode of the photocoupler P2 are made of Ti of the local line.
At the p-side and one end of the resistor R1, the photocoupler P1
And the anode of the photocoupler P2 are connected to the other end of the resistor R1 and one end of the resistor R2.

The other end of the resistor R2 is connected to the capacitor C and the cathode of the diode D, and the other end of the capacitor C and the anode of D are connected to the Ring side of the central line. The emitters of the photocouplers P1 and P2 are G
The collector is connected to ND (ground), and the collector is connected to a central control unit (not shown) of the main body of the electronic exchange.

In such a structure, in the normal idle state, GND (ground potential) is provided on the Tip side of the station line.
, And −48 [V] is applied to the Ring side of the central line. When a linger signal (usually 16 Hz, 85 Vrms) superimposed on -48 [V] is sent from the station side to the station line trunk, the linger signal becomes a capacitor C and a resistor R.
Via a resistor R1 and a photocoupler P1 (or P
2) and the phototransistor on the secondary side of the photocoupler P1 (or P2) is turned on. The central control unit, which is a control circuit of the main body of the electronic exchange, detects this and determines that the call has arrived.

An inverted signal is used when the call is released. Normally, the inverted signal has a polarity (Tip side is positive (GND) and Ring side is negative (-48V)) connected to the office line. Station side is reversed (Tip side is negative (-48
V), the Ring side is positive (GND)). Then, when the inverted signal is sent out, a direct current flows through the station line Ring side, the diode D, and the resistor R2 to the resistor R2.
1 and the photo coupler P2, and the photo coupler P2
Turn on the phototransistor on the secondary side of. The central control unit of the main body of the electronic exchange detects this and determines that it is a reversal.

By the way, in general, if the detection level Vin of the ringer detection circuit 32a is set too low, an incorrect call may be received due to the induction of a ringer signal sent from the station side to other circuits, so it is set to a certain level higher. There is a need.

Further, the detection level Vre of the polarity reversal detection circuit 32b causes a call from the station side even when the contact K of the relay 33 is turned on, a direct current loop is formed, and the voltage between Tip / Ring of the station line becomes low. Since it is necessary to detect the inversion signal indicating the opening, if the detection level Vre is set high, the polarity inversion signal cannot be detected. Therefore, it is necessary to set the detection level Vre to some extent low.

In the conventional circuit, the photocoupler P is used as an adjusting circuit for adjusting the detection sensitivity of the photocouplers P1 and P2 for detecting the ringer signal and the polarity inversion signal.
The resistor R1 connected in parallel with the resistors P1 and P2 and the resistor R2 connected in series with the photocoupler are shared. for that reason,
There is a problem that when the detection level of the ringer signal is increased, the detection level of the polarity inversion signal is also increased accordingly, and when the level of the polarity inversion detection is decreased, the ringer detection level is also decreased accordingly. It was

FIG. 6 illustrates a ringer detection / polarity inversion detection circuit 32 as a ringer detection circuit 32 in order to easily understand FIG.
a and the polarity reversal detection circuit 32b are shown separately, and the fact that the above-mentioned inconvenience occurs will be described in detail with reference to FIG.

FIG. 6A shows a general circuit of the photocouplers P1 and P2, which is a circuit portion for performing the detection operation in the ringer detection circuit 32a and the polarity inversion detection circuit 32b. The ringer detection level and the inversion are shown. In calculating the detection level, as shown in FIG. 6A, the detection level V _ON of the central control unit is V _ON = 2.5 [V], and the pull-up resistor R = 1.
Assuming 00 [KΩ], collector current I _C = (2.5
[V] / 100 [KΩ]) = 0.025 [mA]. Then, the input current I _F and forward voltage at this time are I _F = 0.1
[MA] and V _F = 0.9 [V].

Next, in FIG. 6B which is a circuit diagram of the photocoupler P1 which is a circuit portion for performing the detection operation in the ringer detection circuit 32a, the input current I _FP for turning on the photocoupler P1 is I _FP = 0.1. [MA], forward voltage V _FP = 0.
9 [V], assuming that the current flowing through the resistor R2 and the capacitor C connected in series to the photocoupler P1 is I, the current flowing through the resistor R1 connected in parallel to the photocoupler P1 is I- _IFP . Ringer detection circuit 32 at this time
Voltage Vin between the Tip and Ring of the local line necessary for the operation of a.
[V _PK ] is Vin = ((V _FP / R1) + I _FP ) × (R2 + (1 / ωC)) + V _FP (1)

Next, in (c) of FIG. 6 which is a circuit diagram of the photocoupler P2 which is a circuit portion for performing the detection operation in the polarity reversal detection circuit 32b, the input current I _FP for turning on the photocoupler P2 is I _FP = 0.1 [mA], forward voltage V _FP =
Assuming that the current flowing through the resistor R2 and the diode D connected in series to the photocoupler P2 is 0.9 [V], and the forward voltage of the diode D is V _D = 0.6 [V], the photocoupler P2 is connected in parallel. The current flowing through the resistor R1 is I
-It becomes I _FP . At this time, the voltage Vre [V _dc ] between the Tip and Ring of the station line is Vre = ((V _FP / R1) + I _FP ) × R2 + V _D + V _FP (2)

Now, in FIGS. 6B and 6C, the resistors R1 and R2 are common and R1 = 22 [KΩ], R2 =
100 [KΩ], and the capacitance of capacitor C is 0.47 [μ
F], the voltages Vin and Vre between the Tip and Ring of the station line for operating the ringer detection circuit 32a and the polarity inversion detection circuit 32b are Vin = ((0.9 [V] / 22 [KΩ]) + 0.1 mA) × (100 [KΩ] + (1/2 + π + 16 [Hz] +0.47 [μF]) + 0.9 [V] = 18.0 [V] Vre = ((0.9 [V] / 22 [KΩ]) + 0. 1 mA) × 100 [KΩ] +0.6 [V] +0.9 [V] = about 15.6 [V].

As described above, the photo coupler for level detection is used as the ringer detection circuit 32a and the polarity inversion detection circuit 32b.
Although P1 and P2 are separate from each other, since the resistors R1 and R2 for adjusting the level of the photocoupler are common, one of the conventional ringer detection circuit 32a and the polarity reversal detection circuit 32b detects one of them. It was difficult to make a large difference between the level and the other detection level.

[0030]

As described above, in the conventional system, the resistors connected in series to the photocoupler for adjusting the ringer detection level and the polarity inversion detection level are commonly used. Therefore, when trying to raise the detection level of the ringer signal, the detection level of the polarity reversal signal goes up with it, and conversely, when trying to lower the level of the polarity reversal detection, the ringing detection level goes down accordingly. was there.

Generally, the detection level Vi of the ringer detection circuit is
If n is set too low, it may be erroneously received by other circuits due to the induction of the ringer signal sent from the station side, so it is necessary to set it to a high level to some extent, and the detection level Vre of the inversion detection circuit is A DC loop is formed by the DC circuit of the trunk circuit, and the Tip / Ring of the station line
Even if the voltage between the two becomes low, the station side must detect the inversion signal indicating the release of the call.
If re is set high, the polarity inversion signal cannot be detected. Therefore, it is necessary to set the detection level Vre low to some extent.

However, even if the photocoupler for level detection is separate for the ringer detection circuit and the polarity inversion detection circuit, the resistance for adjusting the level of the photocoupler is common, so the detection level of the ringer is raised. However, there is a problem in that it is difficult to lower the polarity inversion detection level due to the circuit configuration.

Therefore, the object of the present invention is to
It is an object of the present invention to provide a ringer detection / polarity inversion detection circuit capable of increasing the ringer detection level and decreasing the polarity inversion detection level.

[0034]

In order to achieve the above object, the present invention is configured as follows. That is, a ringer detection / detection for detecting an alternating current ringer signal and a direct current office line polarity reversal signal from the local line, which are connected to a two-lined station line.
In the polarity inversion detection circuit, there are two sets of detection elements that have a directivity of energization and operate when an applied voltage becomes a forward voltage to detect a signal, and a detection element that is connected in antiparallel to each other and a detection level. First level adjusting means, which is formed by connecting in series a first resistance for adjustment and a capacitor for passing an AC component, a second resistance for detecting level adjustment, and a directional element for passing a station line polarity inversion signal. And are connected in series, and the first
The second level adjusting means is connected in parallel to the level adjusting means of 1., and the detection element is connected to the local line through a parallel circuit of the first and second level adjusting means.

[0035]

In the above structure, the detecting element has a directivity of energization, and is constituted by using two sets of elements which operate when the applied voltage becomes a forward voltage and detect a signal, which are antiparallel to each other. Connected and connected between office lines. Since the parallel circuit of the first level adjusting means for passing the AC component and the second level adjusting means for passing the station line polarity inversion signal is connected in series to the anti-parallel circuit of the detecting element, the AC ringer signal is obtained. Is applied to the station line, the ringer signal passes through the first level adjusting means and is applied to the detection element, and the detection element in which two sets of detection elements are connected in anti-parallel has a forward voltage with respect to itself. Is operated and outputs a detection signal.

When the station line polarity inversion signal is applied to the station line, the station line polarity inversion signal is applied to the detection element through the second level adjusting means which passes only the direct current component, and the detection element is self-contained. On the other hand, the side which becomes the forward voltage operates by this station line polarity inversion signal and outputs a detection signal.

According to the present invention, the first resistor for adjusting the ringer detection level is connected to the capacitor side through which the AC signal of the ringer flows, and a direct current (diode) that causes a DC current of the inverted signal to flow when the polarity on the station side is reversed. By connecting a second resistor for polarity reversal detection level adjustment to the rectifier element side), it is possible to separate the routes of the AC component and the DC component and adjust the level for each component. Since the polarity reversal detection level can be set individually, polarity reversal detection can be performed even when a DC loop is formed, and a ringer detection / polarity reversal detection circuit without false incoming call detection can be obtained.

[0038]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram of a ringer detection / polarity inversion detection circuit 32 showing an embodiment of the present invention. In FIG. 1, P1 and P2 are photocouplers, the primary sides of these photocouplers P1 and P2 are connected in parallel in opposite directions, and one end side thereof is connected to the Tip side of the central line. The photo coupler P1 is for detecting a ringer,
The photocoupler P2 is for detecting polarity inversion.

A resistor R1 for shunting a current is connected in parallel to the primary side of the photocoupler P1 for detecting the ringer and the photocoupler P2 for detecting the polarity reversal. C is a capacitor,
R2 and R3 are resistors, D is a diode, the resistor R2 and the capacitor C are connected in series, and the resistor R3 and the diode D are connected in series, and these series circuits are connected in parallel. The anode side of the diode D is the ring of the local line.
Side, and the cathode side is connected to the resistor R3. The other ends of the photocouplers P1 and P2 on the primary side are resistors R2 and R3, a diode D, and a capacitor C.
Is connected to the Ring side of the central office line.
Next, the operation of the present apparatus having such a configuration will be described.

Normally, GND on the Tip side of the station line and R of the station line
Since -48 [V] is applied to the ing side, the ringer signal from the station side is superimposed on -48 [V] and sent to the station line trunk circuit. When the ringer signal superimposed on −48 [V] is sent to the trunk line trunk circuit, this signal is transmitted to the resistor R
Since it flows through 2 and the capacitor C, it becomes an input current of the photocoupler P1 (or P2), and the photocouplers P1 and P2 operate to detect an incoming call.

That is, the AC ringer signal operates the photocouplers P1 and P2 to turn on the phototransistor on the secondary side thereof, and the AC ringer signal is transmitted from the phototransistor to the central control unit of the exchange. ..

When the Tip-Ring of the station line is inverted, the diode D becomes a forward voltage, and a current flows from the Ring side to the Tip side through the resistor R3. At this time, the primary side of the photocoupler P2 is It becomes a forward voltage and turns on. Therefore, the photocoupler P2 operates to turn on the phototransistor on the secondary side of the photocoupler P2, and an inverted signal of the polarity is transmitted from the phototransistor to the central control unit of the exchange.

The point that the photocouplers P1 and P2 are operated by the ringer signal to detect the ringer signal is similar to the conventional case, but in the circuit of the present invention, the capacitor C and the photocoupler P1, are used. The difference is that the resistor R2 connected between P2 is dedicated to the ringer detection level adjustment.

Further, when the inverted signal is sent, the direct current becomes the input current of the photocoupler P2 via the diode D, and the reverse detection is the same as in the conventional case, but the diode D and the resistor R3 are dedicated to the reverse detection. Is different from the conventional one.

FIG. 2 shows the ringer detection circuit and the inversion detection circuit separately to make FIG. 1 easy to understand. (A) shows a photocoupler circuit, and (b) shows a ringer detection circuit 32a. Circuit, and (c) is the polarity reversal detection circuit 3
2b shows the circuit. Next, the detection level will be calculated for a specific example with reference to FIG.

FIG. 2 (a) is the same as FIG. 6 (a), and the input current I _F, which is derived from this figure, is I _F.
= 0.1 [mA], and the forward voltage V _FP is V _FP = 0.9 [V]
The same as the conventional circuit.

Next, in FIG. 2B, assuming that the input current I _FP that the photo coupler P1 turns on is 0.1 [mA] and the forward voltage V _FP that the photo coupler P1 turns on is 0.9 [V].
The current flowing through the resistor R1 connected in parallel to the photocoupler P1 becomes I-I _FP , and the voltage Vin [V _PK ] between Tip / Ring at this time is Vin = ((V _FP / R1) + I _FP ) × ( R2 + (1 / ωC)) + V _FP (11)

Next, in FIG. 2C, the input current I _FP for turning on the photocoupler P2 is 0.1 [mA], the forward voltage V _{FP for} turning on the photocoupler P2 is 0.9 [V], and the photocoupler P2 is connected in parallel. The current flowing through the connected resistor R3 and diode D is I, and the forward voltage VD of the diode D is V
When D = 0.6 [V], the current flowing through the resistor R1 connected in parallel to the photocoupler P2 becomes I- _IFP ,
The voltage Vre [Vdc] between Tip / Ring at this time is Vre = ((V _FP / R1) + I _FP ) × R3 + V D + V _FP (12)

In FIGS. 2B and 2C, the resistor R1 is common and R1 = 22 [KΩ] and R2 = 150 [K].
Ω], R3 = 47 [KΩ], C = 0.47 [μF],
From the equations (11) and (12), Vin = ((0.9 [V] / 22 [KΩ]) + 0.1 [mA]) × (150 [KΩ] + (1/2 × π × 16 [Hz ] × 0.47 [μF])) + 0.9 [V] = about 25.0 [V] Vre = ((0.9 [V] / 22 [KΩ]) + 0.1 [mA]) × 47 [KΩ] +0.6 [ V] +0.9 [V] = about 8.1 [V], and the ringer detection level Vin can be set to about 25.0 [V] and the polarity reversal detection level Vre can be set to about 8.1 [V].

In this way, the resistor R2 for sensitivity adjustment of the circuit for ringer detection and the resistor R3 for sensitivity adjustment of the circuit for polarity reversal detection are separated, and the influences of each other are affected by the capacitor C and the diode D, respectively. With the configuration in which they are eliminated, the sensitivity can be adjusted independently of each other. Therefore, it is possible to set the ringer detection level high and the polarity inversion detection level low.

When the ringer signal is superimposed on -48 [V], Vin-Vre> 48 [V], and -48 [V]
Since there is a sufficient level difference with the polarity reversal signal applied to the local line by reversing the polarities of [V] and GND, by adjusting the resistor R3 for adjusting the level for polarity reversal detection, the polarity reversal is performed by the ringer signal. It is possible to eliminate the concern that the detection circuit will operate.

As described above, the present invention provides a ringer detection / polarity inversion detection circuit which is connected to a two-line office line and detects an AC ringer signal and a DC station line polarity inversion signal from the station line. , A detection element having two sets of detection elements that have a directivity of energization and operate when an applied voltage becomes a forward voltage to detect a signal, and a detection element for detecting level adjustment, The first level adjusting means in which the first resistance and the capacitor for passing the AC component are connected in series, the second resistance for adjusting the detection bell and the directional element for passing the station line polarity inversion signal are connected in series. And a second level adjusting means connected in parallel to the first level adjusting means, wherein the detection element is connected to a local line through a parallel circuit of the first and second level adjusting means. It is configured.

In such a structure, the detection element has a directivity of energization, and is constituted by using two sets of elements which operate when the applied voltage becomes a forward voltage and detect signals. They are connected in antiparallel and are connected between office lines. Since the parallel circuit of the first level adjusting means for passing the AC component and the second level adjusting means for passing the station line polarity inversion signal is connected in series to the anti-parallel circuit of the detecting element, the AC ringer signal is obtained. Is given to the station line,
The ringer signal passes through the first level adjusting means and is applied to the detection element, and the detection element in which two sets of detection elements are connected in anti-parallel operates on the side having a forward voltage with respect to itself to output the detection signal.

When the station line polarity inversion signal is applied to the station line, the station line polarity inversion signal is applied to the detection element through the second level adjusting means which passes only the direct current component, and the detection element self-operates. On the other hand, the side which becomes the forward voltage operates by this station line polarity inversion signal and outputs a detection signal.

As described above, according to the present invention, the first resistor for adjusting the ringer detection level is connected to the capacitor side where the AC signal of the ringer flows, and the direct current of the inverted signal flows when the polarity on the station side is reversed. By connecting the second resistor for polarity reversal detection level adjustment to the active element (rectifier element such as diode) side, it becomes possible to adjust the level for each AC component and DC component by dividing the route. Since the ringer detection level and the polarity reversal detection level can be set individually, the polarity reversal detection can be performed even when the DC loop is formed, and the ringer detection / polarity reversal detection circuit without false incoming call detection can be obtained.

[0057]

As described above in detail, according to the present invention, it is possible to provide a ringer detection / polarity inversion detection circuit capable of increasing the ringer detection level and decreasing the polarity inversion detection level. it can.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a circuit diagram for easily understanding the circuit of FIG.

FIG. 3 is a block diagram showing a configuration of an electronic exchange.

FIG. 4 is a block diagram showing a configuration of an office line trunk.

FIG. 5 is a circuit diagram showing a configuration of a conventional circuit.

6 is a circuit diagram for easily understanding the conventional circuit of FIG.

[Explanation of symbols]

31, 31a to 31n ... Trunk circuit, 32 ... Ringer detection / polarity inversion detection circuit, 32a ... Ringer detection circuit, 32
b ... Polarity inversion detection circuit, 40 ... Local line trunk circuit, P
1, P2 ... Photo coupler, C ... Capacitor, R1, R
2, R3 ... Resistance, D ... Diode, C ... Capacitor.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoshi Shirato 1-1, 3-1, Asahigaoka, Hino City, Tokyo TOSHIBA Communication Systems Engineering Co., Ltd.

Claims (1)

[Claims] 1. A ringer detection / polarity inversion detection circuit for detecting an alternating current ringer signal and a direct current station line polarity reversal signal from the station line, which are connected to a two-line office line, A detection element having two sets of detection elements that operate when the applied voltage becomes a forward voltage to detect a signal, and are connected in antiparallel to each other; a first resistance for detection level adjustment; and an AC component. The first level adjusting means, in which a capacitor for passing through is connected in series, and the second resistor for detecting level adjustment and a directional element for passing a station line polarity inversion signal are connected in series. And a second level adjusting means connected in parallel to the level adjusting means, wherein the detection element is connected to a local line through a parallel circuit of the first and second level adjusting means. Detection / polarity inversion detection circuit.