JP2001127875A - Telephone equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cancel unnaturalness that a sound volume becomes smaller or larger just after closing a line or after a dial operation and further to cancel unnaturalness that the sound volume becomes smaller or larger by a microphone mute operation in the middle of speaking. SOLUTION: Concernig the telephone equipment with which a telephone line network 1 and telephone equipment 24 close the line through a cross point SW circuit 23 capable of disconnecting/switching the route of audio signal transmission/reception and form an audio path, receiving AGC is turned off and a fixed gain is written and monitored in a microphone mute state by each of mute operations at the time of receiving or originating call and in the middle of speaking according to the instruction of a control part 5. Afterwards, an operation for forming full-duplex speakerphone operation is formed by turning on the receiving AGC and canceling microphone mute.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for reproducing a received voice signal input from a telephone line as a sound output from a speaker and transmitting a transmitted voice signal collected by a microphone to the telephone line at the same time. The present invention relates to a telephone device (speaker phone) that enables heavy hands-free communication.

[0002]

2. Description of the Related Art In recent years, a telephone device has been added with a speakerphone function that allows a user to talk without having to use a receiver. In order to avoid having to hold the handset in hand and bring it close to the ear, a speaker that converts the received voice signal into an acoustic signal and reproduces the sound signal is used. If the received voice signal reproduced from the speaker reaches the microphone for collecting the transmitted voice signal, howling may occur. However, it is possible to prevent howling of a telephone with a speaker by using an echo canceller technology (devices: dedicated devices are recently prepared for these devices). by this,
A more natural full-duplex speakerphone is possible. Also, in a telephone having a speakerphone function, it is necessary to keep the level of a received voice signal reproduced sound from a speaker at an appropriate level. It has an AGC (Auto Gain Controller) circuit built-in to fulfill this function. Also,
There is a half-duplex speakerphone that does not have an echo canceller, but this is a system in which a telephone conversation is switched by switching between transmission and reception.

[0003]

However, when the line is closed by the line closing circuit at the time of an incoming call, one of the transformers is lost.
The line current rapidly flows to the secondary side, and large pulse-like noise is generated on the secondary side of the transformer. This noise is
When input to the C circuit, the receiving AGC circuit makes the gain extremely small and adjusts the output for large noise to be within an appropriate level. Although the operation of automatic gain adjustment responds instantaneously in the direction to suppress the increase in volume,
The operation in the direction of increasing the sound volume has a slow characteristic. Although such a characteristic is preferable to suppress excessive output, if the recovery takes a long time after the gain becomes extremely small due to the large pulse-like noise generated in the transformer, the However, there is a problem that the volume of the received voice reproduced from the beginning is low at first, and the volume gradually becomes appropriate over time, which is unnatural.

Further, in recent years, in order to make a telephone call by selecting a carrier, it has become necessary to download data such as call charges at that time. At this time, control is performed to mute the microphone for a certain period of time in order to determine whether the data is download data or a call even if a response is made with a speakerphone. The speakerphone circuit (modem part) determines whether to download data or call
DTMF detection etc. to make a decision. The microphone mute is muted by the transmission AGC circuit in the speakerphone circuit (modem unit). As a result, the received voice reproduced during the mute and after the mute is released changes. The reason for this is that when both the microphone and the speaker are released, full-duplex operation is performed.In this case, the echo canceller works on the AGC circuit to suppress the speaker volume or to prevent the howling from occurring. It operates by suppressing the input level. Then, when the microphone is muted, howling does not occur, so that the echo canceller does not work (becomes half-duplex operation), and the receiving AGC circuit is held at the gain amount when operating at full duplex. . Therefore, the speaker volume always changes depending on the gain amount of the receiving AGC circuit immediately before the mute of the microphone. This is small at first, and gradually becomes appropriate and unnatural as time goes by. It becomes large and suddenly unsuitable and unnatural at first, and sometimes large and sometimes small. Problems arise.

Similarly, at the time of transmission, when the line is closed by pressing the speakerphone key of the operation unit, the microphone is muted by the transmission AGC circuit in the speakerphone circuit (modem unit) in order to perform the dial operation from now on. I have.
As a result, the volume of the received voice output from the speaker 21 changes during mute and after mute is released. The reason is that when both the microphone and the speaker are released, they operate at full-duplex.However, in this case, the speaker volume is suppressed so that no howling occurs, and the microphone input level is suppressed. I do. And when the microphone is muted, howling does not occur,
The echo canceller does not work (becomes half-duplex operation), and the receiving AGC circuit is held at the gain amount when it was operating at full duplex. For this reason, the value of the speaker volume always changes depending on the gain amount of the reception AGC circuit immediately before muting the microphone. Therefore, the volume of the DT (dial tone) that is heard from the speaker is suddenly loud at first, or low at first, and the volume gradually becomes appropriate over time, which is unnatural, or remains loud or low. Problem arises.

The same applies to the RBT (ring back tone) after dialing.

[0007] Further, the polarity of the line voltage is inverted by the closing of the telephone line of the other party, and the direction of the current flowing to the primary side of the transformer changes abruptly. However, there is an unnatural problem that the volume is low immediately after the start of a call and becomes appropriate over time.

[0008] Similarly, there is a microphone mute operation during a call. This is a function that is used, for example, for an operation of only listening to information such as a weather forecast from a speaker. In some cases, the user performs a microphone mute operation to change to a half-duplex operation. At this time, since the echo canceller does not work (becomes half-duplex operation), the receiving AGC circuit when operating at full duplex is held at the gain amount at that time, as described above. For this reason, the speaker volume always changes depending on the gain amount of the reception AGC circuit immediately before muting the microphone. This is only required if the gain value of the AGC circuit is appropriate. However, if the gain value is small, the volume heard from the speaker is very low, and if the gain value is large, the sound is broken and it is difficult to hear.

In the prior art, with respect to a change in volume due to polarity reversal noise due to the closing of a telephone line, there is a process of disconnecting the circuit for a certain period of time after the polarity reversal, but the setting of the modem is changed before and after the polarity reversal. Change, microphone mute operation related to a series of operations of the speakerphone, and the receiving AG
Turn off C, set a fixed gain value to this AGC circuit as a set value, and when microphone mute is released, receive AGC
Turning on and operating as a full-duplex speakerphone does not address any unnatural changes in volume.

An object of the present invention is to provide a microphone mute operation and a receiving-side AGC off in a series of operation of the speakerphone, set a fixed gain value as a set value in this AGC circuit section, and release the microphone mute. By turning on the receiving AGC and operating as a full-duplex speakerphone,
An object of the present invention is to provide a telephone device capable of suppressing an unnatural change in volume and producing a clear volume.

[0011]

Accordingly, in the present invention, the full-duplex operation of the speakerphone and the half-duplex operation with the fixed gain set by turning off the receiving AGC are set separately to provide a more stable and natural operation. It allows you to get a call.

In the first aspect, a telephone line is connected to a primary side of a transformer, a secondary side of the transformer, a speaker for reproducing a received voice signal as an audio output, and a microphone for collecting a transmitted voice signal. In between, it has an automatic gain adjusting means for properly maintaining the levels of the receiving voice signal and the transmitting voice signal, and an echo canceling means for performing echo canceling processing, and operates as a full-duplex speakerphone. In a telephone device that operates as a half-duplex speakerphone with the automatic gain adjustment means on the receiving side held by the gain amount at that time and operating as a half-duplex speakerphone, the microphone is muted when making a call to the telephone line, and the automatic A control means for turning off the gain adjusting means and setting a fixed gain value as a set value in the automatic gain adjusting means. The provided.

According to a second aspect of the present invention, the control means turns off the automatic gain adjusting means on the receiving side as it is when receiving the RBT after transmitting the dial signal, and sets a fixed gain value to the automatic gain adjusting means as a set value. If the polarity inversion is detected using the polarity inversion detection means, the receiver automatic gain adjustment means is turned on after the fixed time has elapsed, the microphone mute is released, and the telephone is ready to talk. Control.

According to a third aspect of the present invention, a telephone line is connected to a primary side of a transformer, and a secondary side of the transformer, a speaker for reproducing a received voice signal as an audio output, and a microphone for collecting a transmitted voice signal. In between, it has an automatic gain adjusting means for properly maintaining the levels of the receiving voice signal and the transmitting voice signal, and an echo canceling means for performing echo canceling processing, and operates as a full-duplex speakerphone. In the telephone device operating as a half-duplex speakerphone with the automatic gain adjusting means on the receiving side being held at the gain amount at that time and operating as a half-duplex speakerphone, the automatic gain adjusting means on the receiving side is turned off at the time of an incoming call from the telephone line. The automatic gain adjusting means includes a control means for setting a fixed gain value as a set value. Apparatus.

According to a fourth aspect of the present invention, the control means uses means for counting the elapse of a fixed time after an incoming call, and turns on the automatic gain control means on the receiving side after the elapse of the fixed time;
Release the microphone mute and control to make it possible to talk.

According to a fifth aspect of the present invention, a telephone line is connected to a primary side of a transformer, a secondary side of the transformer, a speaker for reproducing a received voice signal as an audio output, and a microphone for collecting a transmitted voice signal. In between, a full-duplex speakerphone is provided with an automatic gain adjusting means for appropriately maintaining the levels of the received voice signal and the transmitted voice signal, an echo canceling means for performing an echo canceling process, and an operating means for performing a microphone mute operation. It operates, but when the microphone is muted, the echo canceller does not work, and the automatic gain adjusting means on the receiving side is held at the gain amount at that time, and the telephone apparatus operates as a half-duplex speakerphone. When the microphone mute operation is performed, the automatic gain adjustment means on the receiving side is turned off, and the automatic gain adjustment is performed. It provided a control means for setting the gain value of the fixed as a set value in the unit. In claim 6, the control means, after a microphone mute operation during a call,
In response to the microphone mute release operation being performed, the microphone mute is released and the automatic gain control means on the receiving side is turned on, and control is performed so that a call can be made.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a schematic electrical configuration of a speakerphone 24 according to an embodiment of the present invention. A telephone network 1 such as a public telephone network includes a line closing circuit 2 for closing a line.
To the primary side of the transformer 3. Transformer 3
A hybrid circuit 4 is connected to the secondary side of, and sorts a received voice signal and a transmitted voice signal. A main control unit 5 realized by a microcomputer or the like and controlling the telephone device 24 according to a preset program;
When the user performs a pressing operation on the operation unit (speaker phone key) 6, the controller performs a control for operating a function as a speaker phone. Amplifiers 7, 8, 9, and 10 are provided for electrically amplifying the transmission voice signal and the reception voice signal. Signal processing for the transmission voice signal and the reception voice signal is performed in the speakerphone communication circuit (modem unit) 11.

The speakerphone communication circuit (modem section) 11
As one digital signal processing semiconductor integrated circuit, echo cancellation and automatic gain adjustment (abbreviated as “AGC”) are performed. A D / A for outputting a transmission voice signal to the hybrid circuit 4 via the amplifier 7 in the speakerphone communication circuit 11
(Digital-to-analog conversion circuit) 12, D / A (analog-to-digital conversion circuit) 13 for outputting a received voice signal via amplifier 10, A / D 14 for receiving a received voice signal from amplifier 8, and transmission from amplifier 9. An A / D 15 for inputting an audio signal is included. An LEC: line-side echo cancel circuit 16 is provided to remove the transmitted voice signal component from the received voice signal. In order to remove the received voice signal component from the transmitted voice signal, an AEC: acoustic side echo cancel circuit 17 is provided. A transmission AGC circuit 18 and a reception AGC circuit 19 are provided as automatic gain adjustment means for performing automatic gain adjustment so that the levels of the transmission voice signal and the reception voice signal are appropriate.

The transmitted voice signal is collected by the microphone 20, amplified by the amplifier 9, input to the A / D 15, and converted into a digital signal. The received voice signal is D /
After being converted into an analog signal by A13, the amplifier 1
At 0, the power is amplified and reproduced as an audio output from the speaker 21. AEC: Sound side echo cancel circuit 17
Prevents the received voice signal reproduced as an audio output from the speaker 21 from being collected by the microphone 20 and transmitted together with the transmitted voice signal. LEC: The line-side echo cancellation circuit 16 is a state in which the transmission voice signal output from the amplifier 7 and supplied to the hybrid circuit 4 is amplified by the amplifier 8 as a reception-side voice signal, and is converted from the A / D 14 to a digital signal. Remove the wrap around.

In this embodiment, the path of the received voice signal from the secondary side of the transformer 3 to the amplifier 8 via the hybrid circuit 4 and the transmission from the secondary side of the transformer 3 to the amplifier 7 via the hybrid circuit 4. A cross point SW circuit 23 capable of switching the path disconnection of the voice signal is provided, and can be controlled by the control unit 5. This cross point S
In the case of W, although not shown, a call of a handset and a switching of a call path of a cordless handset or the like are also performed.
Also, a telephone line polarity reversal detection circuit 22 is inserted between the telephone line network 1 and the line closing circuit 2, and when the polarity reversal of the telephone line is detected, a detection output is given to the control unit 5.

FIG. 2 shows the operation of the control unit 5 of the speakerphone 24 of FIG.

The operation starts from S200. In this state, both the microphone and the speaker are muted. S201
Then, it is determined whether or not an input operation of pressing down on the speakerphone key 6 is performed. When it is determined that the pressing operation is performed, the telephone network 1 is determined in step S202.
It is determined whether or not a calling signal from is received. If it is received, first in S216, the line is closed and a command to connect to the speakerphone communication circuit 11 side is sent to the cross point SW23. Next, in step S217, a wait is applied for a predetermined time according to a command from the control unit 5. This takes into account the polarity reversal noise that occurs when the line is closed, the noise that occurs when the crosspoint SW 23 is connected, and the time until the connection is made given that a wireless unit such as a cordless telephone is connected. Is set. In step S218, the speakerphone communication circuit 11
Then, a setup process of the speakerphone is performed, and in this process, the reception AGC is set to off. In S219, the fixed gain is written to the received AGC. This allows
The state is such that only the received voice signal is in the talking state. Here, a data download signal (DTMF or the like) from the carrier is detected in S220. Here, if it is detected, the speaker is muted, and the data download process of S221 is performed. It returns to standby and waits for speakerphone key input. If the data download signal (DTMF or the like) from the carrier is not detected in S220, the reception AGC is set to ON in S206 by the instruction of the control unit 5,
The microphone mute is released in S207, and the setting of the full-duplex speakerphone is completed in S208. As a result, the input of the voice signal from the other party and the voice input of the own side are opened to the speakerphone call circuit 11, and the call becomes possible.
At 09, a call in the speakerphone state is formed.

Next, when it is determined in step S202 that the calling signal has not been received, the control unit 5 issues an instruction in step S203.
The reception AGC of the speakerphone communication circuit 11 is set to OFF, and the reception AG of the speakerphone communication circuit 11 is set in S204.
Write fixed gain to C. As a result, DT (dial tone) from the telephone line network is heard, but always at a constant volume. In S205, it is determined whether or not a calling operation has been performed on the telephone line network 1. If there is no calling operation, the speaker phone key is pressed again to return to standby. When it is determined that there is a calling operation in S205, a calling operation is executed in S222. After the end of the calling operation, an RBT (ring back tone) is heard. At this time, the settings of S203 and S204 are maintained and the microphone mute operation is continued. Then, the polarity inversion is detected by the polarity inversion detection circuit 22. When the polarity inversion is detected in S223, a wait is performed for a predetermined time set by a command of the control unit 5, the reception AGC is set to ON in S206, and S207 To cancel the microphone mute, and the setting of the full-duplex speakerphone is completed in S208. As a result, the input of the voice signal from the other party and the voice input of the own side are opened to the speakerphone call circuit 11, and the call becomes possible.
At 209, a call in the speakerphone state is formed.

Next, a description will be given of the microphone mute operation during a call in S209.

First, in step S210, if an operation for disconnecting the call is performed, the process ends in step S230 and returns to standby. If the call termination line is not disconnected in S210, it is determined whether or not the microphone mute operation during the call is performed in S211. If the mute operation during the call is not performed, the call is continued in S209. If the microphone mute during a call is executed in the operation unit 6 in S211, the reception AGC of the speakerphone communication circuit 11 is set to OFF in S212 according to a command of the control unit 5, and the reception AGC of the speakerphone communication circuit 11 is fixed in S213. Write the gain. As a result, it operates as a call monitor in S214, and the volume coming from the telephone network is always heard at a constant level. S2
If the microphone mute release operation during the call is not performed at 15, the call monitoring state of S214 is continued. S21
If the microphone mute release operation during the call is performed in step 5, the reception AGC is set to on in step S206 according to a command from the control unit 5,
The microphone mute is released in S207, and the setting of the full-duplex speakerphone is completed in S208. As a result, when the voice signal from the other party is input to the speakerphone call circuit 11 again, the voice input on the own side is opened, and the call becomes possible.
At 209, a call in the speakerphone state is formed.

As described above, according to the embodiment of the present invention, in a series of operations of the speakerphone, when the microphone is muted, the receiving AGC is turned off, and a fixed gain value is set to the AGC circuit unit. By setting as, unnatural volume change at the time of calling, unnatural volume change at the time of incoming call, unnatural volume change at the time of microphone mute operation during a call can be prevented, Even at times, unnatural changes in volume can be prevented.

[0028]

As described above, according to the first aspect of the present invention,
According to the method, a telephone line is connected to a primary side of a transformer, and a receiving voice is transmitted between a secondary side of the transformer and a speaker that reproduces a receiving voice signal as an audio output and a microphone that collects a transmitting voice signal. Equipped with automatic gain adjustment means and echo cancellation means for performing echo cancellation processing that respectively maintain the level of the signal and the transmission voice signal properly, and operates as a full-duplex speakerphone, but when the microphone is muted, the echo canceller does not work, In a telephone device which operates as a half-duplex speakerphone by holding the automatic gain adjusting means on the receiving side with the gain amount at that time, the microphone is muted when calling to the telephone line, and the automatic gain adjusting means on the receiving side is turned off. Since the automatic gain adjusting means includes a control means for setting a fixed gain value as a set value, It is possible to realize a speaker phone there is no change in the natural change in volume and earpiece volume.

According to the second aspect, the control means turns off the automatic gain adjusting means on the receiving side as it is when the RBT is received after the dial signal is transmitted, and sets a fixed gain value to the automatic gain adjusting means. When the polarity inversion is detected by using the polarity inversion detection means, the receiver automatic gain adjustment means is turned on after the fixed time has elapsed, the microphone mute is released, and a state in which communication is possible is established. Is controlled so that R
Even when receiving BT, it is possible to realize a speakerphone free from unnatural volume change and received volume change.

According to the third aspect, the telephone line is connected to the primary side of the transformer, and the secondary side of the transformer, a speaker for reproducing the received voice signal as an audio output, and the transmission voice signal are collected. An automatic gain adjusting means for appropriately maintaining the levels of the received voice signal and the transmitted voice signal and an echo canceling means for performing an echo canceling process are provided between the microphone and the microphone, and the microphone operates as a full-duplex speakerphone. When the muting is performed, the echo canceller does not operate, and the automatic gain adjusting means on the receiving side is held by the gain amount at that time, and the telephone apparatus operates as a half-duplex speakerphone. Control means for turning off the means and setting a fixed gain value as a set value in this automatic gain adjustment means, It is possible to realize a speaker phone there is no change in the natural change in volume and earpiece volume.

According to a fourth aspect of the present invention, the control means uses means for counting the elapse of a fixed time after an incoming call, turns on the automatic gain control on the receiving side after the elapse of the fixed time, and releases the microphone mute. If the fixed time is set to a time that is not affected by the line current that suddenly flows to the primary side of the transformer due to the line closing, the line is closed at the time of the incoming call. The speakerphone can be realized without unnatural volume changes and fluctuations in the reception volume due to the influence of the sound.In addition, if the time is extended to the time for detecting data download, even when the microphone is muted for data download, It is possible to realize a speakerphone free from unnatural volume change and fluctuation in the reception volume.

According to the fifth aspect, the telephone line is connected to the primary side of the transformer, and the secondary side of the transformer, a speaker for reproducing a received voice signal as an audio output, and a transmission voice signal are collected. A full-duplex system is provided between the microphone and the microphone, including automatic gain adjustment means for appropriately maintaining the levels of the reception voice signal and the transmission voice signal, echo cancellation means for performing echo cancellation processing, and operation means for performing a microphone mute operation. While operating as a speakerphone, when the microphone is muted, the echo canceller does not operate, and the automatic gain adjustment means on the receiving side is held at the gain amount at that time, and in a telephone device operating as a half-duplex speakerphone, during a call, In response to the microphone mute operation being performed by the operating means, the automatic gain adjusting means on the receiving side is turned off, and the automatic Because it contains a control means for setting a set value of fixed gain value adjusting means, a microphone mute operation is unnatural volume changes and earpiece volume speakerphone no variation of even be realized during a call.

According to claim 6, the control means cancels the microphone mute and turns on the receiving-side automatic gain control means in response to the microphone mute cancel operation after the microphone mute operation during a call. Therefore, the speakerphone is controlled so as to be in a state in which a call can be made, so that it is possible to realize a speakerphone that does not have an unnatural volume change or a change in the reception volume when the microphone mute operation is performed during a call and then released.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a system according to a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart in the case of operating as a speakerphone.

FIG. 3 is a flowchart in the case of operating as a speakerphone.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Telephone line network 11 Speaker phone communication circuit (modem part) 24 Telephone device

Claims (6)

[Claims] A telephone line is connected to a primary side of a transformer, and a telephone call is received between a secondary side of the transformer and a speaker for reproducing a received voice signal as an audio output and a microphone for collecting a transmitted voice signal. Equipped with an automatic gain adjustment unit and an echo canceling unit for performing an echo canceling process, which respectively maintain the levels of the audio signal and the transmission audio signal properly,
The telephone device operates as a full-duplex speakerphone, but when the microphone is muted, the echo canceller does not operate, and the automatic gain adjustment means on the receiving side is held at the gain amount at that time, and the telephone device operates as a half-duplex speakerphone.
Mute the microphone when making calls to the phone line,
A telephone device comprising a control unit for turning off an automatic gain adjusting unit on a receiving side and setting a fixed gain value as a set value in the automatic gain adjusting unit. 2. The control means according to claim 1, wherein the control means turns off the automatic gain adjusting means on the receiving side as it is when receiving the RBT after transmitting the dial signal, and sets a fixed gain value to the automatic gain adjusting means. When the polarity inversion is detected by using the polarity inversion detection means, after the fixed time has elapsed, the receiving side automatic gain adjustment means is turned on, the microphone mute is released, and the telephone becomes ready for communication. A telephone device characterized in that: 3. A telephone line is connected to a primary side of a transformer, and a telephone call is received between a secondary side of the transformer, a speaker for reproducing a received voice signal as an audio output, and a microphone for collecting a transmitted voice signal. Equipped with an automatic gain adjustment unit and an echo canceling unit for performing an echo canceling process, which respectively maintain the levels of the audio signal and the transmission audio signal properly,
The telephone device operates as a full-duplex speakerphone, but when the microphone is muted, the echo canceller does not operate, and the automatic gain adjustment means on the receiving side is held at the gain amount at that time, and the telephone device operates as a half-duplex speakerphone.
A telephone device comprising a control unit for turning off an automatic gain adjusting unit on a receiving side when an incoming call is received from a telephone line, and setting a fixed gain value as a set value in the automatic gain adjusting unit. 4. The control means according to claim 3, wherein said control means uses a means for counting the elapse of a fixed time after an incoming call, and turns on a receiving-side automatic gain adjustment means after the elapse of said fixed time;
A telephone device, which releases a microphone mute and controls so as to be able to talk. 5. A telephone line is connected to a primary side of a transformer, and a receiving side is connected between a secondary side of the transformer and a speaker for reproducing a receiving voice signal as an audio output and a microphone for collecting a transmitting voice signal. An automatic gain adjusting unit that appropriately maintains the levels of the voice signal and the transmission voice signal, an echo canceling unit that performs an echo canceling process, and an operating unit that performs a microphone mute operation, and operates as a full-duplex speakerphone. When the microphone is muted, the echo canceller does not work, and in the telephone device which operates as a half-duplex speakerphone by holding the automatic gain adjustment means on the receiving side with the gain amount at that time, the microphone mute operation is performed by the operation means during a call. In response to this, the automatic gain adjusting means on the receiving side is turned off, and a fixed gain is applied to the automatic gain adjusting means. A telephone device comprising control means for setting a value as a set value. 6. The control means according to claim 5, wherein the control means releases the microphone mute and turns on the receiving-side automatic gain control means in response to the microphone mute release operation after the microphone mute operation during a call. A telephone device for controlling the telephone device to be in a callable state.