JPS6093867A - Calling reception circuit - Google Patents

Abstract

PURPOSE:To confirm surely a call signal from an opposite station by detecting a call signal of a specific pattern in connection to a demodulator and opening a gate to display it externally when a handset is mounted to an acoustic coupler. CONSTITUTION:An output of a receiver 1 is connected to a receiver 2 and an output of the receiver 2 is given to an acoustoelectric converter 3. An output of the acoustoelectric converter 3 is given to a demodulator 5 via a band pass filter 4. An output of the demodulator 5 is given to a call signal detecting circuit 10 and an output of a calling signal detecting circuit 10 is given to a gate circuit 8. An output of the gate circuit 8 is given to a calling display circuit 9. The acoustic coupler 11 consists of an acoustoelectric converter 3, a band pass filter 4, the demodulator 5 and a calling reception circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a call receiving circuit for an acoustic coupling device that is acoustically coupled to a handset of a telephone and performs data communication over a telephone line.

[Description of prior art]

Conventionally, the calling side is provided with an electroacoustic transducer such as a speaker, and the called side is provided with an acoustoelectric transducer such as a microphone, and these are acoustically coupled to a telephone handset to transmit data. Acoustic coupling devices are widely known and used.

The acoustic coupling unit of this type of acoustic coupling device handles a very low signal level, but the surrounding noise level is quite high, so it is necessary to obtain a predetermined S/N ratio. Therefore, extremely high sound insulation properties are required, and this is achieved using various methods. Therefore, even a fairly large external sound volume is suppressed to the extent that it has almost no effect on the microphone of the acoustic coupling section or the transmitter of the telephone. For this reason, if it is necessary to call the other party for a meeting while the handset of the telephone is attached to the acoustic coupling device, it is very difficult to call the other party using the telephone.

From this, as a way to confirm the call from the other party,
Generally, the following two methods are known.

One is a method in which the local station unilaterally hangs up the call and uses a howling sound to notify the other party that the communication has ended, when the other party's handset is disconnected from the telephone. It is.

The other method is to provide a continuous signal with a single frequency different from the data signal as a calling signal, and use this to call the other station from the own station, identify the calling signal at the other station, and respond to the other party's call. It's a method.

In such a method, a frequency different from that of the data alternating signal is used, such as the howler sound in the former case and the calling signal in the latter case, and the receiving circuit thereof is shown in FIG.

FIG. 1 is a block diagram of a conventional call receiving circuit. In FIG. 1, 1 indicates a telephone set, 2 indicates a receiver,
The receiver 2 converts the electrical signal of the other party into an acoustic signal and outputs it to the acoustic coupling device 11 . 3 is an acousto-electrical converter such as a microphone that converts an acoustic signal from the handset 2 of the telephone 1 into an electric signal. Reference numeral 4 denotes a band pass filter that separates the output of the acoustoelectric transducer 3 into noise and the AC signal used for data transmission. A demodulator 5 demodulates the output of the bandpass filter 4. The telephone set 1, handset 2, acoustoelectric transducer 3, bandpass filter 4, and demodulator 5 correspond to a receiving circuit for general data transmission.

Reference numeral 6 denotes a bandpass filter that selects howler sounds or ringing signals from the telephone, and has a different pass frequency from that of the bandpass filter 4. Since the howler sound and the calling signal have a single frequency, this bandpass filter 6 requires a very narrow passband in order to separate them from noise. =7 is the bandpass filter 6
This is a level detector that detects the level of the output of the sensor, and is a well-known method.

That is, by rectifying the AC signal and comparing the DC voltage with a reference voltage, the output of the level detector 7 is turned on when the input signal is greater than a set threshold level, and the output of the level detector 7 is turned on. The gate circuit 8 is controlled by the output of the gate circuit 8, which is opened and closed.

If a howler sound or ringing signal is detected, the fit
At the same time as controlling the controller 5, the call table water circuit 9 notifies the user of the call visually or audibly using a transmitter and speaker.

Conventionally, in the former method, in order to call the other party, the caller had to hang up his/her own phone and wait for the other party to detect the howling sound, which was a time loss and was complicated in terms of operability. Furthermore, there was a drawback that only the called side of the telephone could receive the howler sound, and the calling side could not be called because there was no howler sound.

The latter method has the disadvantage that if the handset of the local station or the other station is not attached, the signal has a frequency component close to that of a ringing signal, and an erroneous ringing indication occurs in an environment of continuous external noise.

Furthermore, since it is necessary to detect a single frequency different from the data transmission frequency in both the former and the latter, in addition to the bandpass filter 4 that passes the data transmission frequency, a bandpass filter 6 with a very narrow band is used. It is necessary to provide a separate detection circuit, which has the drawback that the detection circuit is complicated and expensive.

[Purpose of the invention]

The present invention detects a ringing signal with a simple circuit configuration, regardless of the calling side or the called side, without the need for time loss or complicated operations when the handset of a telephone is attached to an acoustic coupling device. It is an object of the present invention to provide a paging receiving circuit which achieves this and is extremely unlikely to detect an erroneous paging signal due to surrounding external noise even when a handset is not attached to an acoustic coupling device.

[Features of the invention]

The present invention relates to a call receiving circuit of an acoustic coupling device that performs data transmission by acoustically coupling with a handset of a telephone, in which an output of the handset of the telephone is connected to a path of a demodulated signal, and a call is indicated on the signal. The present invention is characterized in that it includes a calling signal detection circuit that detects that a signal of a specific pattern set in advance is included, and a display means that is activated by the detection output of the calling signal detection circuit.

The display means may be either a visual display means or an audible display means.

rDescription by Examples] Examples of the present invention will be described with reference to the drawings. Second
The figure is a block diagram of an acoustic coupling device including a call receiving circuit according to an embodiment of the present invention. In FIG. 2, the same circuits and equipment as in FIG. 1 are designated by the same symbols as in FIG. The output of the handset 1 is connected to a handset 2, and the output of the handset 2 is connected to an acoustoelectric transducer 3. The output of the acoustoelectric transducer 3 is connected to a demodulator 5 via a bandpass filter 4 .

Here, the feature of the present invention is a call receiving circuit surrounded by a dashed line in FIG. That is, 1M adjuster 5
The output of the paging signal detection circuit 10 is connected to the paging signal detection circuit 10, and the output of the paging signal detection circuit 10 is connected to the gate circuit 8.

The output of the gate circuit 8 is connected to a call display circuit 9.

The acoustic coupling device 11 is constituted by an acoustoelectric transducer 3, a bandpass filter 4, a demodulator 5, and a call receiving circuit of the present invention.

The operation of the acoustic coupling device including the paging receiving circuit having such a configuration will be explained. FIG. 3 is a waveform diagram of the specific pattern of the calling signal. In FIG. 2, telephone 1,
The receiver 2, the acoustoelectric transducer 3, the bandpass filter 4, and the demodulator 5 have the same configuration as the conventional one. First, on the calling side, when calling the other party, it generates a calling signal of a specific pattern (for example, as shown in Fig. 3, a direct current of "0" polarity and "1" polarity at an interval of time T1), and sends data. It is converted into DC and AC using the same method as the signal and sent to the telephone line. On the other hand, on the called side, as shown in FIG. 2, the data transmission AC signal is demodulated by the same procedure as normal data transmission from the telephone 1 to the demodulator 5, and output as a DC signal to the output of the demodulator 5. let The DC signal is input to a paging signal detection circuit 10 connected to a demodulator 5.

The paging signal detection circuit 10 detects the output of the demodulator 5 at a time To
Once the rOJ polarity is detected, the signal is memorized and
If the time is longer than T2, the memory is canceled.

That is, the activation is performed under the time condition of 'ro <"r 1 < T 2 and the polarity is "0". Furthermore, To<Tl<
By detecting "1" polarity during the time T2 and again detecting the rOJ polarity that satisfies the above-mentioned time relationship, it has the function of determining a calling signal, and when a calling signal is determined, the output is used as a calling signal. Turns "on" while detecting, and turns "off" the output when the ringing signal disappears.
do. The gate circuit 8 is conductive only when the output of the paging signal detection circuit 10 is "on", and drives the paging display circuit 9 visually or audibly. An example of a visual drive of the call display circuit 9 is a lamp display. An example of an audible drive for the call indicator circuit 9 is a low frequency oscillator and a loudspeaker excited by the output of this oscillator.

〔Effect of the invention〕

As described above, the present invention provides a ringing signal detection circuit that is connected to a demodulator to detect a specific pattern of ringing signals, a gate that opens and closes according to the output of the ringing signal detection circuit, and a gate that opens and closes when the gate is opened. By equipping the device with a display circuit that visually or audibly displays it externally, it is possible to reliably confirm the calling signal from the other party when the handset is attached to the acoustic coupling device. This has an excellent effect of avoiding displaying an amusing call depending on the environment. Therefore, it is possible to eliminate the troublesome situations where the user does not notice until the howler sound is detected even though the data has ended, or when the user wants to make a call but cannot receive the call.Also, the calling circuit has a simple circuit configuration and can be realized economically. There are advantages.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an acoustic coupling device including a conventional calling signal detection circuit. FIG. 2 is a block diagram of an acoustic coupling device including a calling signal detection circuit according to an embodiment of the present invention. Fig. 3 is a waveform diagram of the calling signal of the specific pattern. demodulator,
7... Level detector, 8... Gate circuit, 9... Calling display circuit, 10... Calling signal detection circuit, 11... Acoustic coupling device. 1 1st 2nd figure foil 3 b

Claims (1)

[Scope of Claims] (11) In a call receiving circuit of an acoustic coupling device that performs data transmission by acoustically coupling with a handset of a telephone, the output of the handset of the telephone is connected to a path of a demodulated signal, and The present invention is characterized by comprising a calling signal detection circuit that detects the inclusion of a signal of a specific pattern set in advance as a signal indicating a calling, and a display means that is activated by the detection output of the calling signal detection circuit. Call receiving circuit. +21 The call receiving circuit according to claim 11, wherein the display means is a visual display means. (3) The call reception circuit according to claim 11, wherein the display means is an audible display means. call receiving circuit.