JPH06318970A - Calling monitoring device - Google Patents

Abstract

PURPOSE:To prevent the continuity of a calling without noticing the on-hook on the side of a calling opposite party, in a calling equipment such as a telephone set, etc. CONSTITUTION:When a calling opposite party performs an on-hook, in order to detect the presence or absence of a tone signal having a prescribed frequency to be transmitted from an exchange 1 to main wires L1 an L2, the signal components of the same frequency as that of the tone signal are eliminated from a calling signal outputted from the call transmitting part 15b of a transmitter/receiver 15 to a calling circuit 14 by a band eliminating filter 21 and only signal components having the prescribed frequency out of the signals on main wires L1 and L2 are allowed to pass through from a bend pass filter 22 to a specified signal detection circuit 23 for outputting a detection signal in accordance with the presence or absence of a signal of the prescribed frequency. A decision means 27 receiving this detection signal decides whether the tone signal is transmitted from the exchange 1 or not by the period measurement of the detection signal and the decision result is notified by a notification means 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a call monitoring device for monitoring the presence or absence of a specific signal from a call partner or a line network in a telephone or the like.

[0002]

2. Description of the Related Art For example, in a two-way two-line type line such as a telephone, one user hears an on-hook operation sound of the other party and a predetermined tone signal from the exchange 1 to make the on-hook of the other party. Knowing that, the user can also use the on-hook operation to end the call.

[0003]

However, in such a conventional telephone, an acoustic coupler is connected to the handset, for example, when the user separates the handset from his / her ear in order to see a memo or the like during a call. Then, when the other party performs an on-hook operation during data communication, the telephone user side has a problem that he / she continues the data communication or the call without noticing the on-hook operation of the other party. This problem occurs even when the user is holding the handset close to his / her ear, when external noise is intense, or when the user is deaf.

To solve this problem, a predetermined tone signal sent from the exchange may be detected. In such a bidirectional two-wire type line, in addition to the tone signal from the exchange, Since the sound input to the transmitter of the handset, that is, the user's voice, external noise, or data sound is superimposed, the tone signal of the exchange can be detected accurately by simply detecting the line signal. Can not be detected.

In order to accurately perform this detection, a method of stopping the input of the transmission signal or a method of inputting the signal on the line and the signal from the transmission section to a differential amplifier and transmitting from the signal on the line Although a method of canceling the speech signal component can be considered, the method of stopping the input of the transmission signal causes a great obstacle to data communication etc. even if the stop period is short. Further, in the method of detecting the differential component between the line signal and the transmission signal, the transmission signal component on the line can be completely canceled due to the mismatch between the transmission impedance of the transmission unit and the transmission impedance of the line. Therefore, it is difficult to accurately detect the tone signal.

An object of the present invention is to solve this problem and to provide a call monitoring device capable of accurately detecting a predetermined signal sent from the line side without causing any trouble in data communication and the like.

[0007]

In order to solve the above-mentioned problems, the call monitoring apparatus of the present invention has a voice on the call line through a call circuit connected to one end of a bidirectional two-wire call line. A signal is output from the earpiece and the voice input to the transmitter is transmitted to the call line via the call circuit. The call device is provided with the call line other than the call line. A call monitoring device for monitoring the presence or absence of a specific signal of a predetermined frequency sent from an end side, the call sending signal being provided between the sending section and the calling circuit, and being output from the sending section. A band elimination filter for inputting a signal from which the signal component of the predetermined frequency has been removed to the speech circuit, a band pass filter for extracting only the signal component of the prescribed frequency from the signal on the speech line, and the band pass filter. From the filter Receiving the signal, a specific signal detecting means for outputting a detection signal corresponding to the presence or absence of a signal component of said predetermined frequency, receiving a detection signal from said specific signal detecting means,
And a determination unit that determines whether or not the specific signal is present on the communication line.

[0008]

With this configuration, in the call monitoring apparatus of the present invention, only the signal obtained by removing the signal component of the predetermined frequency from the transmission signal is transmitted to the communication line via the communication circuit, and the signal on the communication line is transmitted. Only the signal component of the predetermined frequency is extracted, and it is determined whether or not there is a specific signal on the communication line from the detection signal according to the presence or absence of that signal.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a telephone 1 having a call monitoring device according to an embodiment and connected to terminals of office lines L1 and L2 from an exchange 1.
0 configuration is shown.

The office lines L1 and L2 connected to the terminals 11a and 11b of the telephone 10 are connected to the call circuit 14 via the hook switch 12 and the dial device 13.
The hook switch 12 is turned on by the off-hook operation of the handset 15 connected to the call circuit 14, forms a loop between the station lines L1 and L2 and the call circuit 14, and the loop current due to the power supply of the exchange 1 is supplied. Office lines L1 and L2
Shed on. Due to this loop current, the exchange 1 side determines that the telephone set 10 connected to the office lines L1 and L2 is in the off-hook state.

The dial device 13 sends a dial signal corresponding to the dial number operated by the user to the exchange 1.
Send to the side. The exchange 1 receives this dial signal and makes a call to the line of that number.

The call circuit 14 sends the voice signals on the office lines L1 and L2 to the receiving section 15a of the handset 15, and the handset 15
The voice signal input from the transmitter 15b of the
Transmit to 2 side.

The band pass filter 21 of the call monitoring device 20 is provided between the call transmitter 15b of the handset 15 and the call circuit 14.
Are connected. The bandpass filter 21 greatly attenuates a signal component in an extremely narrow band centered on the frequency Ft and passes signal components in other voice bands with low loss, as shown in the characteristic of the amount of attenuation versus frequency in FIG. It is configured so as to output only the signal obtained by removing the signal component of the frequency Ft from the transmission signal of the transmission unit 15b to the communication circuit 14.

A band pass filter 22 for extracting a signal component of frequency Ft from the signals on the station lines L1 and L2 is connected to the station lines L1 and L2 between the call circuit 14 and the hook switch 12. .

As shown in the characteristic of the amount of attenuation vs. frequency in FIG. 3, the band-pass filter 22 passes only a signal component in a narrow band centering on the frequency Ft with low loss, and signals in other voice bands. It is configured to greatly attenuate the component.

The output of the bandpass filter 22 is input to the specific signal detection circuit 23. The specific signal detection circuit 23,
The signal passed through the band pass filter 22 is detected by the wave detector 24, and the detected output is wave-shaped by the wave shaper 25,
A detection signal is output according to the presence / absence of a signal of frequency Ft on the office lines L1 and L2.

This detection signal is input to the judging means 27. The determination means 27 determines whether or not the input detection signal is a tone signal from the exchange side due to on-hook of the other side by measuring the cycle of the detection signal, and outputs the determination result to the display means 28. To do. This cycle determination is performed by comparing the H level time Ta of the detection signal and the L level time Tb that follows it with the intermittent cycle (previously known cycle) of the tone signal output from the exchange 1 when the other party is on-hook. Be done.

When the judging means 27 judges that the cycle of the detection signal is a predetermined cycle, the notifying means 28 turns on a lamp or the like to notify the user that the other party on the hook is on-hook.

Next, the operation of this telephone will be described.
First, after the telephone user off-hooks the handset 15 to form a loop formed by the office lines L1 and L2 and the call circuit 14, when the user operates the dial device 13 according to the dialed number of the other party, the exchange is performed. 1 detects the off-hook of the handset 15 of the telephone 10 by the loop current and makes a call to the line of the number corresponding to the dial signal transmitted to the office lines L1 and L2.

In response to this call, the other party performs an on-hook operation to start a call, and as shown in FIG. 4 (a), the band elimination filter 21 removes the transmission signal from the transmission section 15b. A signal in which the signal component of the frequency Ft is removed and the transmission signal of the other party shown in FIG. 4B are superimposed appears on the station lines L1 and L2.

The transmission signal from which the signal component of the frequency Ft is removed is transmitted to the other party as it is, but the removal band is very narrow as described above, and the voice on the user side should be changed greatly. No, it is transmitted to the other party.

As shown in FIG. 2 (c), the specific signal detection circuit 23 detects that the detection output of the signal component of the frequency Ft among the signals transmitted to the station lines L1 and L2 is larger than a predetermined threshold value. Only the detection signal that becomes H level is output.

The judging means 27 judges whether or not the cycle of the detection signal is a predetermined value. However, the cycle of the detection signal is irregular as during this call, and the H level time Ta and the L level time Tb thereof are determined. Are greatly different from each other, and neither of them coincides with the intermittent period of the predetermined tone signal, it is determined that this detection signal does not correspond to the tone signal from the exchange 1, and as shown in (d) of FIG. Does not output the judgment signal.

While the telephone user does not notice,
When the other party on the call first goes on-hook and the tone signal of the frequency Ft by the other party on-hook is sent from the exchange 1 at a predetermined intermittent period as shown in (b) of FIG. 5, the specific signal detection circuit 23 As shown in (c) of FIG. 5, a detection signal that is at the H level is output only while the tone signal is present.

At this time, even if the user's voice or external noise is input as shown in FIG. 5A, the signal component of the frequency Ft in the voice signal is transmitted to the station lines L1 and L2. Since it is not transmitted, the detection signal from the specific signal detection circuit 23 has a period equal to the intermittent period of the tone signal from the exchange 1.

When the judging means 27 judges that the H level time Ta and the L level time Tb of the detection signal are substantially equal to each other and equal to the intermittent period of the predetermined tone signal, the judgment signal shown in FIG. It is sent to the notification means 28. Receiving the determination signal, the notification means 28 displays to the user that the other party on the hook is on-hook by a lamp or the like. By this notification, the on-hook of the other party of the call can be known and the call can be immediately terminated even when the external noise is severe or the user is deaf.

[0027]

Other Embodiments In the above embodiment, the band elimination filter 20 for removing the signal component of the frequency equal to the frequency of the specific signal from the transmission signal is always connected between the transmission unit and the speech circuit. However, a band elimination filter is inserted between the transmitter and the call circuit at a predetermined cycle, and the level of the detection signal of the specific signal detection circuit 27 is checked at each insertion timing to determine the presence or absence of the specific signal. You may do it.

Further, in the above embodiment, the judgment result of the judgment means is notified to the user by the notification means such as a lamp. However, the judgment result disconnects the line of the telephone or the operation of other control units. You may make it regulate.

Further, in the above-mentioned embodiment, an example in which the present invention is applied to a telephone which does not directly collect a fee is shown, but the present invention can be similarly applied to a telephone of a fee collecting type and other communication equipment.

[0030]

As described above, the call monitoring apparatus of the present invention transmits only the signal obtained by removing the signal component of the predetermined frequency from the transmitted signal to the call line through the call circuit, and transmits the signal on the call line. Extract only the signal component of the specified frequency from
Since it is configured to determine whether or not there is a specific signal on the communication line from the detection signal according to the presence or absence of that signal, the presence or absence of the specific signal to be monitored adversely affects normal calls and communications. Can be performed accurately without being affected by the voice input to the transmitter.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of a telephone including a call monitoring device according to an embodiment.

FIG. 2 is a characteristic diagram of a main part of one embodiment.

FIG. 3 is a characteristic diagram of a main part of one embodiment.

FIG. 4 is a signal diagram of each unit in a normal call state.

FIG. 5 is a signal diagram of each part when the call partner goes on hook.

[Explanation of symbols]

 1 Switchboard 10 Telephone 12 Hook Switch 13 Dial Device 14 Call Circuit 15 Handset 15b Transmitter 20 Call Monitoring Device 21 Band Elimination Filter 22 Band Pass Filter 23 Specific Signal Detection Circuit 27 Judgment Means 28 Notification Means

Claims (1)

[Claims] 1. A voice signal on the call line is output from a receiver through a call circuit connected to one end of a two-way two-line call line, and a voice input to a transmitter is called. A call monitoring device that is provided in a call device that transmits to the call line through a circuit, and monitors the presence or absence of a specific signal of a predetermined frequency sent from the other end of the call line among the signals on the call line. A band remover that is provided between the transmitter unit and the communication circuit and that inputs a signal obtained by removing the signal component of the predetermined frequency from the transmitter signal output from the transmitter unit to the communication circuit. A filter, a band-pass filter that extracts only the signal component of the predetermined frequency from the signals on the communication line, and a detection signal that receives a signal from the band-pass filter and that corresponds to the presence or absence of the signal component of the predetermined frequency Out A call monitoring device comprising: a specific signal detecting unit for determining whether or not the specific signal is present on the communication line by receiving a detection signal from the specific signal detecting unit. .