KR0128556Y1 - Ling back signal detecting circuit of automatic telephone - Google Patents

Abstract

The present invention relates to a ring color signal detection circuit of an automatic telephone call to detect a ring back signal such as a ring signal or a busy signal coming from an exchange in an automatic telephone call included in a wireless security system.

The present invention detects the ringback signal at the same time and compares the signal corresponding to the detected level and frequency, thereby recognizing the type of ringback signal, to detect the ringback signal more accurately.

Description

Ring back signal detection circuit of automatic telephone call

1 is a conventional ringback signal detection circuit diagram.

2 is a ringback signal detection circuit diagram according to the present invention.

Figure 3 (a) is a conventional detection signal, (b) is a detection signal according to the present invention.

* Explanation of symbols for main parts of the drawings

10: telephone call IC 20: signal amplifier

31: Integral circuit 32: Schmitt trigger

32,33: tone decoder 40: microcomputer

The present invention relates to a ring back signal detection circuit of an automatic telephone alert, and in particular, to automatically detect a ring back signal such as a ring signal or a busy signal from an exchange in an automatic telephone alert included in a wireless security system. The present invention relates to a ringback signal detection circuit of a telephone call.

In general, the automatic telephone call included in the wireless security system determines ringback signals such as ring signal, busy signal, voice signal, etc. inputted from the exchange and memorizes them in advance. It is a system that performs a function of notifying a message by a telephone call.

In the conventional ringback signal detecting circuit in the automatic telephone call, as shown in FIG. 1, the ringback signal (RING BACK SIGNAL) coming from the exchange through the telephone line is inputted to the telephone circuit IC 10, and the telephone circuit. The IC 10 amplifies the input signal and then removes the noise component, and the output signal of the telephone circuit IC 10 is amplified by about 20 to 30 times again by the signal amplifier 20 having two stages. The amplified signal is rectified by the diode D1 and then integrated in the integrating circuit 30. The integrated signal detects the period of the input signal by switching the transistor Q1 on and off. .

The detected period is input to the microcomputer 40, and the microcomputer 40 determines whether a busy signal, a ring signal, or a voice signal is used as a period of each input signal.

The conventional signal detection circuit is rectified in the diode D1, but includes a large amount of high frequency components, which are noise components, and also tends to cause errors and delays in bias setting of the transistor for detecting the period of the signal. Since it is difficult to accurately set the conduction / blocking of the signal, the ringback signal component has a ripple at a low level, which is a level recognized by the microcomputer 40 in the busy signal (a) and the ring signal (b) shown in FIG. There was a problem in that the component does not contain the correct cycle in the microcomputer.

In addition, although good data is detected in an ideal telephone line state where the sensitivity is substantially good and there is little noise, there is no actual ideal telephone line and a lot of noise occurs in a real situation, so the microcomputer recognizes the data and checks the period. In case of discriminating heavy signal (signal which is ON state for 0.5 seconds, off state repeating for 0.5 seconds) and ring signal (signal which is ON state for 1 second and off state repeating for 2 seconds), There is a problem in that data errors occur frequently, which makes accurate signal detection impossible.

The present invention has been made to solve the above-mentioned conventional problems.

Accordingly, it is an object of the present invention to provide a ringback signal detection circuit of an automatic telephone call notification to accurately detect a ringback signal such as a ring signal or a busy signal coming from an exchange in an automatic telephone call included in a wireless security system.

As a technical means for achieving the above object, the present invention provides a telephone circuit IC for amplifying a ringback signal from an exchange through a telephone line and removing noise, and a signal amplifier for amplifying the output signal of the telephone circuit IC in two stages. A ringback signal detecting circuit comprising a portion and a diode for rectifying a signal from the signal amplifier,

Integrating means for integrating a ringback signal from the diode;

Level detecting means for detecting a level of the output signal of the integrating circuit and outputting the level to the microcomputer;

First frequency detecting means for detecting a frequency of the ring signal from the diode and outputting the frequency to the microcomputer;

Second frequency detecting means for detecting a frequency of the busy signal from the diode and outputting the frequency to the microcomputer;

And a microcomputer for comparing the input level detection signal and the frequency detection signal to recognize the type of the signal coming through the telephone line.

Hereinafter, with reference to the accompanying drawings of the present invention.

In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

2 is a ringback signal detection circuit diagram according to the present invention.

Referring to FIG. 1, the ringback signal detecting circuit of the automatic telephone communication according to the present invention includes a telephone circuit IC 10 for amplifying a ringback signal from an exchange through a telephone line and removing noise, and the telephone circuit IC 10. Signal amplification section 20 for amplifying the output signal of the second stage, diode D1 for rectifying the signal from the signal amplification section 20, and an integration circuit for integrating the ringback signal from the diode D1. (31), the Schmitt trigger (32) which detects the level of the output signal of the integrating circuit 31 and outputs it to the microcomputer, and detects the frequency of the ring signal from the diode (D1) and outputs it to the microcomputer. The first tone decoder 33 and the second tone decoder 34 which detects the frequency of the busy signal from the diode D1 and outputs it to the microcomputer are compared with the input level detection signal and the frequency detection signal. Come in through the phone line It is composed of the microcomputer 40 to recognize the type of signal.

It can be seen that the level detecting means corresponds to the Schmitt trigger 32, and the first and second frequency detecting means correspond to the tone decoders 33 and 34 including an RC circuit that is externally adjustable and determines a reference frequency. have.

Figure 3 (a) is a detection signal for the conventional busy signal (a) and the ring signal (b), (b) is a level detection signal (a) and a frequency detection signal for the busy signal according to the present invention ( b).

Hereinafter, the action and effect according to the present invention will be described in detail based on the accompanying drawings.

Referring to FIGS. 2 and 3, the ring signal generated from the actual exchange is repeated at 440 Hz + 480 Hz for 1 second on, 2 seconds off, and the busy signal at 480 Hz. + 620Hz is synthesized and remains on for 0.5 seconds and off for 0.5 seconds.

The signal amplified by the telephone circuit IC 10 and the two-stage signal amplifier 20 as shown in FIG. 2 is biased in the 440 Hz band for the ring signal and 620 Hz for the busy signal. Such a ringback signal is rectified by the diode D1 but contains many high frequency components which are still noise components. In the conventional circuit, the Schmitt trigger using an operational amplifier is used in the present invention in order to widen the bias point and reduce the delay of the switching using the transistor.

When the signal included in the ringback signal is determined only by the level detection of the ringback signal using the Schmitt trigger, the exact timing is set, but the interference by the instantaneous impulse and noise, or the separation between the ring, the busy tone, and the voice Due to the unfavorable relationship, the frequency input means uses the first and second tone decoders 33 and 34 as the frequency detection means to detect the frequency and input the signal to the microcomputer.

The first and second tone decoders 33 and 34 operate basically the same, except that the reference frequencies determined by the RC circuits R1 and C1 (R2 and C2) are different, and the first and second tone decoders 33 and 33 are different. (34) outputs a low level signal when the frequency of the input signal is equal to the reference frequency. The first tone decoder 33 is set to detect the frequency of the ring signal, and the second tone decoder 34 is set to detect a busy signal.

For example, when the ringback signal is a ring signal, the signal detected by the Schmitt trigger 32 and the frequency detected by the first tone decoder 33 are input to the microcomputer 40, so that the microcomputer 40 On the other hand, when the ringback signal is a busy signal, the signal detected by the level of the Schmitt trigger 32 and the frequency detected by the second tone decoder 34 are input to the microcomputer 40. Thus, the microcomputer 40 recognizes the input of the busy signal.

The microcomputer 40 compares an input port P1 and an input terminal P2 signal or an input terminal P1 and an input terminal P3 signal to determine a ringback signal as described above. When a slight difference (delay, irregular signal due to noise, high signal, etc.) occurs between frequency detection signals, the ringback signal is more accurately determined by comparing about 3 frames.

FIG. 3 (b) shows the level detection and the frequency detection when the ringback signal is a busy signal, and it can be seen that a square wave much more stable than a conventional switching transistor can be obtained. Even if a slight delay (30mS) occurs between the level detection and the frequency detection signal, the microcomputer makes a tolerance to detect the ringback signal more reliably.

The above description is only a description of an embodiment of the present invention, and the present invention is capable of various changes and modifications within the scope of its configuration.

Claims (3)

A telephone circuit IC 10 for amplifying a ringback signal from the exchange through a telephone line and removing noise; a signal amplifier 20 for amplifying the output signal of the telephone circuit IC 10 in two stages; CLAIMS 1. A ringback signal detection circuit comprising a diode (D1) for rectifying a signal from a section (20), comprising: an integration means (31) for integrating a ringback signal from the diode (D1); Level detecting means (32) for detecting a level of the output signal of the integrating circuit (31) and outputting it to a microcomputer; First frequency detecting means (33) for detecting a frequency of the ring signal from the diode (D1) and outputting it to a microcomputer; Second frequency detecting means (34) for detecting a frequency of the busy signal from the diode (D1) and outputting it to a microcomputer; And a microcomputer (40) for comparing the input level detection signal and the frequency detection signal to recognize the type of the signal coming through the telephone line. The ring back signal detection circuit according to claim 1, wherein the level detecting means (32) comprises a Schmitt trigger. 2. The ringback signal detection circuit according to claim 1, wherein the first and second frequency detection means (33, 34) comprise a tone decoder including an externally adjustable RC circuit for reference frequency.