JPH07107196A - Tone detecting circuit for voice response equipment - Google Patents

Abstract

PURPOSE:To realize the detection of a tone such as a dial tone, a busy tone, etc., in the case of connecting a line in the voice response equipment for conducting calling processing through a telephone line by a miniature circuit configuration, and also, to covert it to an LSI. CONSTITUTION:A start-stop synchronous signal line 5 for connecting an A/D converter 21 for allowing a tone signal to be subjected to digital conversion and a start-stop synchronization type interface 33 is provided, the tone signal subjected to digital conversion is inputted to the start-stop synchronization type serial interface 33, and by measuring and discriminating a frequency and a sending-out interval of the tone signal by a CPU 31, a dial tone, a busy tone, etc., of the tone signal are detected. Accordingly, the tone detection can be realized by a digital circuit and can be converted easily into an LSI, and also, since the start-stop synchronization type serial interface circuit can be combined, there is an effect which can miniaturize the circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice response device for communicating between a telephone and a computer via a telephone line, and in particular, distinguishes and detects tone signals such as dial tone and busy tone when connecting to the line. The present invention relates to tone detection of a voice response device in which a line is disconnected as needed to improve line utilization efficiency.

[0002]

2. Description of the Related Art A conventional voice response device is disclosed in, for example, NEC Technical Report Vo1.41 No. As shown in FIG. 3 of P73 of 11/1988, a dedicated line such as T-DET was provided for tone detection. The T-DET is an analog circuit.

[0003]

For this reason, there is a problem in miniaturization and economic efficiency such that it is not suitable for LSI, and it is necessary to prepare a dedicated LSI in order to miniaturize the device.

The object of the present invention is realized by utilizing a general-purpose asynchronous serial interface circuit included in a voice response device without specially providing a dedicated tone detecting circuit, thereby achieving miniaturization and LSI implementation. Is possible.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a circuit for converting tone signals such as dial tone, busy tone and ringing tone into digital signals when a line is connected, and a general-purpose asynchronous serial interface. This is achieved by a tone detection circuit which is provided with an asynchronous signal line for connecting circuits and which inputs a digitally converted tone signal to an asynchronous serial interface to detect and detect a tone signal.

[0006]

The tone detection circuit according to the present invention converts the tone signal into a digital signal by the A / D conversion circuit. Focusing only on the sign bit of tone signals such as dial tone, busy tone, ringing tone, etc., which have been digitally converted, the change in logic state is used as an asynchronous serial data signal, and an asynchronous serial interface circuit is provided through an asynchronous signal line. To enter. The CPU measures the reception interval, data content, etc. of the input digital data according to the frequency and generation interval of the tone signal, and distinguishes between dial tone, busy tone, ringing tone, etc. Perform detection.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment of the drawings. In FIG. 1, reference numeral 1 is a line control unit for making and receiving calls by the NCU 11 and the NCU control circuit 12 through a telephone subscriber line 6, sending a melody sound as a service sound to a user, communicating with a partner device through the line, and the like. In order to do so, it receives and sends a PB (push button) signal.
An audio processing unit 2 reproduces audio and controls PB reception. The voice signal is digitally encoded for each phrase,
The audio data is stored in an external audio memory (not shown), and audio data is sequentially read from the designated memory area according to an instruction from the system control unit, converted into analog audio, and sent to the line. These processes are performed by the A / D converter 21, the D / A converter 2
2, coder / decoder 23, and audio processor 2
4 etc. 3 is a system control unit, CP
U31 controls the system of each control unit, controls the interface of the host computer 4, and executes various remote operations of voice. Reference numeral 32 is a memory, 33 is an asynchronous interface, and 5 is an asynchronous signal line connecting the A / D converter 21 and the asynchronous serial interface 33.

In the above, in order to communicate between the telephone and the computer via the telephone line,
Information for the computer is entered from the PB of the telephone,
Information from the computer is converted to voice and flows from the handset. Therefore, to connect to the telephone line 6, the CPU 31
Controls the NCU 11 via the NCU control unit 12.
After the line is connected, a dial tone (tone O in FIG. 2) is transmitted from the telephone line 6 as a tone signal. This signal is first input from the NCU 11 to the voice processing unit 2 and converted into a digital signal (signal A in FIG. 2) by the A / D converter 21.
After the dial tone is converted into a digital signal, the signal A focusing only on the polarity bit is input from the line 5 to the asynchronous interface circuit 33 as an asynchronous signal. CP
The U31 has a start bit (ST) of 1 bit and a data bit (DAT) as a frame format of start / stop synchronization.
By setting A) to 7 bits and stop bit (SP) to 1 bit, in the case of dial tone O, data will be continuously received at a cycle of 2.5 ms (f = 400 Hz). From the contents of the data, the CPU 31 calculates and measures the frequency of the input signal A and the transmission interval, and determines and detects the dial tone O. In the case of busy tone, 0.5s
Data is intermittently received at a cycle (f = 2 Hz), and busy tone can be determined by measuring the frequency of this tone signal and the transmission interval.

Therefore, the presence or absence of the dial tone O can be determined by measuring the tone signal, and the busy tone after the selection signal is transmitted can be detected. Based on the detection of the tone signal, it is possible to perform processing such as disconnecting the line as necessary to improve the line utilization efficiency.

[0010]

As described above, according to the present invention, the tone signal of the telephone line can be detected by a digital circuit, and the detection can be performed by using a general-purpose asynchronous interface circuit. Therefore, the circuit including the tone detection circuit can be made into an LSI, and the start-stop synchronization interface used for communication with the host is also used, so that the number of parts can be reduced, downsizing and cost reduction can be achieved.

[Brief description of drawings]

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

FIG. 2 is a signal waveform diagram for explaining the present invention.

[Explanation of symbols]

1 ... Line control unit, 2 ... Voice processing unit, 3 ... System control unit, 4 ... Host, 5 ... Start / stop synchronization signal line, 6 ... Telephone line, 11 ... NCU, 12 ... NCU control unit, 21 ... A / D
Converter, 22 ... D / A converter, 31 ... CPU, 33 ... Asynchronous interface.

Claims (1)

[Claims] 1. A voice response device for communicating between a telephone and a computer via a telephone line, wherein an A / D conversion for converting a tone signal such as a dial tone or a busy tone when a line is connected into a digital signal. A voice characterized in that a start / stop synchronization signal line for connecting the circuit and the start / stop synchronization type serial interface is provided, and the tone signal converted to digital is input to the start / stop synchronization type serial interface to detect and detect the tone signal. Tone detection circuit of the transponder.