JPS63221751A - Ring tripping circuit - Google Patents

Abstract

PURPOSE:To constitute a ring tripping circuit without employing a capacitor by measuring a period when the current of a ringer circuit is positive and negative so as to detect the ring trip. CONSTITUTION:A ringer current detection and separating circuit 6 provided in series with the ringer sending path of a subscriber circuit, generates a signal pulsized corresponding to the polarity of the current of the ringer circuit. Then a positive pulse width measuring circuit 7 digitizes and outputs the pulse width corresponding to the current of the ringer circuit, and a negative pulse width measuring circuit 8 digitizes and outputs the pulse width corresponding to the current of the ringer circuit. A subtraction circuit 9 generates an output subtracting the output of the measuring circuit 8 from the output of the measuring circuit 7, and when the output exceeds a value preset in a threshold value register 11, a comparator 10 discriminates it and generates the output.

Description

[Detailed Description of the Invention] [Summary] When a ringer circuit responds to a ringer circuit (when a ringer circuit responds), the period in which the current in the ringer circuit becomes positive and the period in which it becomes negative are equal, so this time difference can be When the detection value exceeds a predetermined value several times in succession, response detection is performed.

[Industrial application field]

The present invention relates to an improvement of a ring trip circuit in a telephone exchange, and particularly to a ring trip circuit suitable for miniaturization and LSI implementation.

Ring trip circuit, ha! ;l11! This function is installed in the subscriber circuit of the machine to detect the response of the dead subscriber when making an N1 call, but especially in the case of a digital electronic exchange, the subscriber circuit is equipped with BOR8HT functions (power supply, overvoltage protection, calling , monitoring, 2W-4W conversion.

Each function of the test) is consolidated, and the system
The volume and price ratio is 10,000. Therefore, there is a strong demand for miniaturization and economicalization of the C subscriber circuit, and among the above-mentioned functions, it is desired that the ring 1771 circuit for detecting a response at the time of a call can also be miniaturized.

[Conventional technology]

FIG. 4 shows an example of a conventional ring TL knob circuit. 1 is the subscriber (telephone), and during a call, the relay contacts rt1 and rt@ are switched to the positions shown to supply power and detect loops.

A coupling circuit 2 forming part of a subscriber circuit that performs 2W-4W conversion and cooperating (CODεC) functions is connected to the NW side of an exchange (not shown) via C1. On the other hand, when calling, contact rt1. rL1 is switched to the opposite side, forming a ringer delivery path from the ringer signal generator 3 to the subscriber line LH+ L2 and the telephone amltt °C ringer output path from the telephone 1
A ringami stream consisting of low-frequency alternating current flows through the ring to make a call.

When the subscriber answers (turns off), a DC path is formed through the telephone line n 'C, and since DC current flows from the power supply ε superimposed on the ring current, the DC component t is extracted via the low-pass filter circuit 4. By extracting the 'C output through the photocoupler 5, a response at the 'C1 subscriber (telephone*) 1 is detected.

FIG. 5 shows another example of the conventional ring trip circuit, in which a low-pass filter circuit 4A including a °C operational amplifier A is included in place of the low-pass filter circuit 4 in FIG. The direct current is separated from the ringer current and detected, and a C response detection output can be obtained through the photocoupler 5.

[Problem that the invention seeks to solve]

In the conventional switching circuit shown in FIGS. 4 and 5, a low-pass filter circuit is used to convert the current ρλ of the ringer circuit into a DC current 4. They are detected separately, thereby detecting the response of the subscriber C. In this case, the ringer signal usually has 16 to 25 outputs and has a low frequency, so the value of the capacitor of the low-pass filter for separating the signals becomes large. For example, in the circuit of FIG. 4, the value of capacitor CI is about 50 μF, and even in the circuit of FIG. 5, the value of capacitors C, , C, is about 1 μF. In addition, the ringer voltage is a signal of about 75 to 90 Vrm*, and since the DC voltage g (-48 V) is superimposed on it, the peak voltage will be about 200 V, so it is necessary to consider the withstand voltage of the conditioner/su. .

Conventional glue/glue trip circuits such as PM are difficult to miniaturize and have rarely been used.

[Means for solving problems]

The present invention is intended to solve the problems of the prior art, and has a basic configuration as shown in FIG. , comparison means 106 , and continuity detection means 10
4 to constitute a C1,1 ring tri-knob circuit.

The current detection means 101 is connected in series with the ringer delivery circuit and generates a signal indicating the respective positive and negative time lengths of the current in the ringer circuit.

The subtraction means 102 generates an output obtained by subtracting the negative time length from the positive time length of the current in the ringer circuit.

Comparing means 105 determines that the output value of subtracting means 102 exceeds a preset threshold and generates an output.

The continuity detection means 104 outputs a detection signal indicating the subscriber's response when the output of the comparison means 105 occurs a plurality of times in succession.

[Effect]

A ringer current detection and separation circuit 6 provided in series with the ringer sending path of the subscriber circuit generates a pulsed signal corresponding to the positive or negative of the current in the ringer circuit, and a C1 positive pulse width measuring circuit 7 The pulse width corresponding to the positive value of the current in the ringer circuit is digitized and outputted, and the pulse width corresponding to the negative value of the current in the ringer circuit is digitized by the negative pulse width measuring circuit 8. Output. generates an output by subtracting the output value of the negative pulse width measurement circuit 8 from the output value of the positive pulse width measurement circuit 7 by the subtraction circuit 9;
When this output value exceeds a value preset in the threshold register 11, the comparison circuit 10 determines this and generates an output. When such an output occurs a plurality of times in succession, the state continuity detection circuit 12 determines this state and generates a detection signal indicating the subscriber's response.

〔Example〕

FIG. 2 shows an embodiment of the present invention, in which the same parts as in FIGS. 4 and 5 are designated by the same numbers, 6 is a ringer current detection and separation circuit, 7 is a positive pulse width measurement circuit, 8 is a negative pulse width measuring circuit, 9 is a subtraction circuit, 10 is a comparison circuit, 11 is a threshold register, and 12 is a state continuity detection circuit.

Fig. 6 shows the input/output signals of the ringer current detection and separation circuit 6 in Fig. .

In FIG. 2, when C1 is called, a ringer current flows through the current detection and separation circuit 6. When there is no response, as shown in FIG. 6(a), only 97 current flows through the Otocoupler 5.
produces an output voltage of C@1” and corresponds to a negative period °C””
0'' output voltage. The ringer signal is approximately sinusoidal and therefore the output voltage has a 120 period To
and the period T of @0'' are equal.

On the other hand, during response, a direct current IDO flows superimposed on the ringer current, but the direction of this current matches the positive direction of the ringer current. Therefore, as shown in FIG. 6 (bl), as the period T of 1# in the output voltage becomes longer, @
The period T of 0# becomes shorter.

In FIG. 2, the positive pulse width measuring circuit 7 measures the positive pulse width, that is, the period Tot', and outputs it as one digital value. Further, the negative pulse width measuring circuit 8 measures the negative pulse width, that is, the period T1, and outputs it as a digital value. The subtraction circuit 9 subtracts the output digital value of the negative pulse width measuring circuit 8 from the output digital value of the positive pulse width measuring circuit 7, and the Cb digital value is 0 when there is no response and when there is no response. It becomes a certain value only in time. Comparison circuit 10 compares the output value of subtraction circuit 9 with a threshold digital value preset in threshold value register 10, and generates an output signal when the output value of subtraction circuit 9 exceeds the threshold value. Such an operation is performed for each cycle of the ringer signal, and the continuity detection circuit 12 in the n1 state performs two or more consecutive cycles to generate an output that detects the subscriber's response when the output signal of the C comparison circuit 10 is generated. do.

The threshold value set in the threshold value register 10 is determined by taking into account the leakage resistance value of the line, the loop resistance limit, etc.
Since a malfunction may occur when the output signal is activated or when noise occurs, the state continuity detection circuit 12 detects whether an output signal has been generated from the C1 ratio calibration circuit 11 two or more times in succession. The response (off-hook) detection is performed only when the off-hook is detected.

The circuit shown in FIG. 2 is dimmerized at 0.degree. C. except for the ringer current detection and isolation circuit 60, and this section is constructed by a logic circuit.

〔Effect of the invention〕

As explained above, according to the present invention, a ring trip circuit can be constructed without using a capacitor. Also, except for the ringer current detection and separation circuits, the circuit is composed of logic circuits, making it suitable for CLSI implementation. Therefore, according to the present invention, it is possible to downsize the ring trip circuit.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the principle configuration of the present invention, Fig. 2 is a diagram showing an embodiment of the present invention, Fig. 5 is a diagram showing the input/output of the ringer current detection and separation circuit, 4 and 5 are diagrams each showing an example of the configuration of a conventional ring trip circuit. 1...Subscriber (telephone) 2...Coupling circuit 6...S/G+S signal generator 4.4A...Low pass filter circuit 5...7 Otokabura 6...Ringer current detection Separation circuit 7... Positive pulse width measurement circuit 8... Negative pulse width measurement circuit 9... Subtraction circuit 10... Comparison circuit 11... Threshold register

Claims (1)

[Claims] Current detecting means (101) connected in series to the ringer sending circuit and generating signals indicating the time lengths of positive and negative periods of current in the ringer circuit, and the time lengths of the positive periods. A subtraction means (
102), and comparison means (103) that generates an output when the output value of the subtraction means (102) exceeds a predetermined threshold;
Continuity detection means (104) generates an output signal when the output of the comparison means (103) occurs a plurality of times in succession, and the output signal of the continuity detection means (104) is used to detect the subscriber's A ring trip circuit characterized by detecting a response.