JPH08242279A - Telephone set - Google Patents

Abstract

PURPOSE: To properly make a speech by each volume of transmission, reception, and sidetone even when a line power source voltage is connected to the NTT line of 48V or to the private exchange or the like with the low power source voltage of 24V, etc. CONSTITUTION: A volume correcting characteristic adjustment circuit 8a or 8b with dissimilar volume correcting characteristics, which one is best to the line power source voltage to be detected by a voltage detecting circuit 12, is connected to a transmission/reception volume correcting circuit 4 by a switching circuit 12. Thus, the best volume correcting characteristic is set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone device in which the volume of a handset is corrected with a predetermined volume correction characteristic according to circuit loss.

[0002]

2. Description of the Related Art FIG. 7 is a block diagram showing a configuration of a conventional telephone device. In the figure, (1) is the NTT line (L1) (L
2) or a modular jack connected to a private branch exchange, etc., (2) is a diode bridge for matching the polarity of the line power supply voltage, (3) is a line control unit that closes and opens the line, and (4) is , A transmission / reception volume correction circuit such as a speech circuit having a transmission attenuator (4a) that corrects the transmission volume against line loss, and a reception attenuator (4b) that corrects the reception volume, and (5) is the transmission sound and the reception sound. (6) is a transmitter such as a microphone, (7) is a receiver such as a speaker, and (8) is a volume correction characteristic adjustment circuit that sets the characteristics of the above transmission / reception volume correction circuit (4). , (9) are control microcomputers (hereinafter referred to as microcomputers) for managing and controlling the entire telephone device.

Next, the operation will be described. First, the line controller (3) is controlled by the microcomputer (9), and when the line is closed, the call becomes possible. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4).
The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. Therefore, the reception signal is gain-adjusted by the reception attenuator (4b) and applied to the receiver (7).

When the transmission signal is collected by the transmitter (6), the gain is adjusted by the transmission attenuator (4a),
Output from the transmission / reception volume correction circuit (4). This signal is sent to the line controller (3) and diode bridge (2), modular (1)
Is output to the line through. Here, by the volume correction characteristic adjusting circuit (8), line loss and transmission / reception attenuator (4a),
The gain relationship of (4b) is set to the specified characteristic, and usually when the line loss is large, the transmission / reception attenuator (4a) (4b)
Is large and the line loss is small, the gain is small.

[0005]

Since the conventional telephone device is constructed as described above, the normal line power supply voltage is 48V.
When a telephone device designed mainly to be connected to the NTT line which is V is connected to a private branch exchange or the like having a low power supply voltage of 24 V or the like, compared to the case where the telephone device is connected to the NTT line. The line current becomes small and the line loss becomes equivalent to a large line loss, and the gains of the transmitting and receiving attenuators (4a) and (4b) automatically increase. However, in reality, the power supply voltage is only low and there is no loss in volume, so conversely, both the transmission volume and the reception volume become too loud, which in turn increases the sidetone, resulting in speaking. There was a problem that it became difficult.

The present invention has been made to solve the above-mentioned problems, and the line power supply voltage N is 48V.
Even if connected to a TT line or connected to a private branch exchange or the like with a low power supply voltage of 24 V or the like, proper transmission is always performed.
It is an object of the present invention to obtain a telephone device capable of making a call at each volume of reception and sidetone.

[0007]

According to a first aspect of the present invention, there is provided a telephone device according to a voltage detecting means for detecting a line power supply voltage supplied from an exchange and a voltage detected by the voltage detecting means. A volume correction characteristic changing means for changing the volume correction characteristic set in the transmission / reception volume correction circuit by the volume correction characteristic adjustment circuit is provided.

A telephone device according to a second aspect of the invention is
In the invention described in claim 1, a plurality of sound volume correction characteristic adjusting circuits having different characteristics are provided, and a plurality of sound volume correction characteristic adjusting means are provided as the sound volume correction characteristic changing means in accordance with the detected voltage by the voltage detecting means. This is a volume correction characteristic switching circuit for switching and connecting the optimum one of the adjusting circuits to the transmission / reception volume correction circuit.

The telephone device according to the invention of claim 3 is
In the invention according to claim 1 or 2, the voltage detecting means is a microcomputer in which a voltage corresponding to the line power supply voltage is applied to its analog-digital conversion port (hereinafter referred to as AD conversion port). .

A telephone device according to a fourth aspect of the invention is
In the invention according to claim 1 or 3, the volume correction characteristic adjusting circuit has a configuration in which the set volume correction characteristic is made variable by an electronic volume, and the volume correction characteristic varying means is responsive to the voltage detected by the voltage detecting means. The configuration is such that the electronic volume is adjusted.

The telephone device according to the invention of claim 5 is
In the invention according to any one of claims 1 to 4, the volume correction characteristic set by the volume correction characteristic adjusting circuit can be selected by a manual operation.

[0012]

According to the first aspect of the present invention, the optimum volume correction characteristic for the line power supply voltage, which is changed according to the line power supply voltage detected by the voltage detecting means, is set in the transmission / reception volume correction circuit. As a result, it is possible to realize a call that is easy to talk with an appropriate sidetone volume.

In a second aspect of the present invention, among a plurality of volume correction characteristic adjustment circuits having different volume correction characteristics, an optimum volume correction characteristic adjustment circuit for the line power supply voltage detected by the voltage detection means is: The volume correction characteristic switching circuit is connected to the transmission / reception volume correction circuit to set the optimum volume correction characteristic.

According to the third aspect of the present invention, the voltage corresponding to the line power supply voltage is digitally converted at the A / D conversion port and input to the microcomputer, and the volume correction characteristic is changed or switched by the microcomputer. The optimum volume correction characteristic for the line power supply voltage is set in the transmission / reception volume correction circuit.

According to another aspect of the present invention, the electronic volume is controlled according to the line power supply voltage detected by the voltage detection means, for example, the A / D conversion port of the microcomputer, and the volume set in the transmission / reception volume correction circuit is set. The correction characteristic is adjusted to the optimum value.

In a fifth aspect of the present invention, the volume correction characteristic switching circuit is manually switched or manually input to the microcomputer via the operation unit, whereby a desired volume correction characteristic is manually transmitted / received and the volume correction is performed. Set in the circuit.

[0017]

【Example】

Example 1. Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of this embodiment, and FIG. 2 is a characteristic diagram for explaining its operation. In the figure, (1) is a modular jack, (2) is a diode bridge, (3) is a line control unit, (4) is a transmission / reception volume correction circuit, (4a)
Is the transmission attenuator of this circuit, (4b) is the reception attenuator, (5) is the balance network, (6) is the transmitter, (7) is the receiver, and (9) is the microcomputer. Similar to the example.

(8a) and (8b) are volume correction characteristic adjusting circuits each having different characteristics, (10) is a line voltage when the line is open,
That is, a voltage detection circuit for detecting whether the line power supply voltage is above or below a predetermined value, (11) is a holding circuit for holding the output of this voltage detection circuit (10), and constitutes a voltage detection means together with the voltage detection circuit (10). . (12) is a volume adjusting circuit for transmitting / receiving a sound volume correction characteristic adjusting circuit (8a) or (8b) according to the output of the holding circuit (11).
The volume correction characteristic switching circuit, which is switched and connected to (4), constitutes volume correction characteristic changing means.

Next, the operation will be described. First, before the line is closed, the voltage detection circuit (10) detects whether the line power supply voltage supplied from the connected exchange is 48V of the NTT line or a low power supply voltage such as 24V from the private branch exchange. The corresponding switching voltage is held by the holding circuit (11) even when the line is closed. The volume correction characteristic switching circuit (12) is controlled by this switching voltage, and the volume correction characteristic adjustment circuit
It is switched to either side of (8a) and (8b).

When making a call, the line control unit (3) is controlled by the microcomputer (9), and the call becomes possible when the line is closed. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4). The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. At this time, the volume correction characteristic switching circuit (12) changes the volume correction characteristic adjustment circuit (8a) according to the line power supply voltage supplied from the connected exchange.
It is switched to either side of (8b). Therefore, the reception signal is subjected to gain adjustment by the reception attenuator (4b) with a characteristic determined by any of the selected volume correction characteristic adjustment circuits (8a) or (8b), and is applied to the receiver (7).

When the transmission signal is collected by the transmission device (6), it is determined by the transmission attenuator (4a) by any one of the selected volume correction characteristic adjusting circuits (8a) and (8b). The gain is adjusted according to the characteristics, and it is output from the transmission / reception volume correction circuit (4). This signal is output to the line through the line controller (3), the diode bridge (2), and the modular (1).

Next, referring to FIG. 2, a transmission / reception volume correction circuit (4)
The gain adjustment operation of will be described. The solid curve (21) in Fig. 2 is the characteristic of the volume correction characteristic adjustment circuit (8a) selected when connected to an NTT line switch with a normal line power supply voltage of 48V. The gain gradually increases with decreasing, and the decrease in the volume of the transmitted and received voice due to the circuit loss is corrected. On the other hand, the chain curve (22) is
Volume correction characteristic adjustment circuit (8b) selected when connected to a private branch exchange with a low line voltage of about 24V
With the characteristic of, the gain does not increase until the circuit current becomes very small compared to the curve (21). Therefore, when the line power supply voltage is low, the circuit current is small and the volume of the transmitted / received sound does not decrease due to the circuit loss. Therefore, unnecessary gain correction is not performed.

Embodiment 2 FIG. Embodiment 2 of the present invention will be described below with reference to the drawings. FIG. 3 is a block diagram showing a schematic configuration of this embodiment. In the figure, (1) is a modular jack, (2) is a diode bridge, (3) is a line controller,
(4) is a transmission / reception volume correction circuit, (4a) is a transmission attenuator of this circuit, (4b) is a reception attenuator, (5) is a balance network, (6) is a transmitter, (7) is a receiver, ( 9) is a microcomputer, and the above is the same as that of the first embodiment shown in FIG.

(8a), (8b) and (8c) are volume correction characteristic adjusting circuits having different characteristics, and (10a) is a voltage detecting circuit for detecting whether the line power supply voltage is above or below a first predetermined value, (Ten
b) is a voltage detection circuit for detecting whether the line power supply voltage is less than or equal to a second predetermined value smaller than the first predetermined value, and (11) holds the outputs of the voltage detection circuits (10a) and (10b). Holding circuit,
(12) is a three-stage output of the holding circuit (11), that is, a first output having a line power supply voltage equal to or higher than a first predetermined value, and a line power supply voltage having a first predetermined value and a second predetermined value. The second output during the interval, or the third output less than the second predetermined value is switched to three stages, and any one of the volume correction characteristic adjusting circuits (8a) (8b) (8c) is switched. This is a volume correction characteristic switching circuit that is switched and connected to the transmission / reception volume correction circuit (4).

Next, the operation will be described. First, before the line is closed, the line power supply voltage supplied from the connected exchanges by the voltage detection circuits (10a) and (10b) is 48V of the NTT line, or a medium line power supply of about 36V from the private branch exchange. A voltage or a low power supply voltage of 24 V is detected, and the switching voltage corresponding to the detected voltage is held by the holding circuit (11) even when the line is closed. The volume correction characteristic switching circuit (12) is controlled by this switching voltage, and the volume correction characteristic adjusting circuit (8a) (8b) (8
It is switched to any one of c).

In the call, the line control unit (3) is controlled by the microcomputer (9), and the call can be made when the line is closed. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4). The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. At this time, the volume correction characteristic switching circuit (12) changes the volume correction characteristic adjustment circuit (8a) according to the line power supply voltage supplied from the connected exchange.
It is switched to any one of (8b) and (8c). Therefore, the reception signal is gain-adjusted by the reception attenuator (4b) with a characteristic determined by one of the selected volume correction characteristic adjustment circuits (8a), (8b) or (8c), and applied to the receiver (7). .

When the transmitter signal is collected by the transmitter (6), the transmitter attenuator (4a) selects one of the selected volume correction characteristic adjusting circuits (8a), (8b) or (8c). ), The gain is adjusted with a characteristic that is determined by, and the sound is output from the transmission / reception volume correction circuit (4). This signal is output to the line through the line controller (3), the diode bridge (2), and the modular (1).

Example 3. The third embodiment of the present invention will be described below with reference to the drawings. FIG. 4 is a block diagram showing a schematic configuration of this embodiment. In the figure, (1) is a modular jack, (2) is a diode bridge, (3) is a line controller,
(4) is a transmission / reception volume correction circuit, (4a) is a transmission attenuator of this circuit, (4b) is a reception attenuator, (5) is a balance network, (6) is a transmitter, (7) is a receiver, ( 8a) (8b) (8c)
Indicates a volume correction characteristic adjusting circuit having different characteristics, and (12) connects any one of the volume correction characteristic adjusting circuits (8a) (8b) (8c) to the transmission / reception volume adjusting circuit (4). The volume correction characteristic switching circuit is the same as that of the second embodiment shown in FIG.

(9) is a microcomputer having an A / D conversion input port (9A) for converting an analog input signal into digital data and inputting it, and of the voltage input to this A / D conversion input port (9A) A switching signal of three stages corresponding to the magnitude is output for controlling the volume correction characteristic switching circuit (12), and operates as a voltage detecting means.

Next, the operation will be described. First, before the line is closed, the voltage corresponding to the line power supply voltage applied to the A / D conversion input port (9A) of the microcomputer (9) is 48V of the NTT line or from the private branch exchange. The microcomputer (9) detects whether the medium line power supply voltage of about 36 V or the low power supply voltage of 24 V is detected, and a switching signal corresponding to the detected voltage is held even when the line is closed. The volume correction characteristic switching circuit (12) is controlled by this switching signal and switched to any one of the volume correction characteristic adjusting circuits (8a) (8b) (8c).

In the call, the line control unit (3) is controlled by the microcomputer (9), and the call becomes possible when the line is closed. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4). The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. At this time, the volume correction characteristic switching circuit (12) uses the switching signal from the microcomputer (9) to adjust the volume correction characteristic adjusting circuits (8a) (8b) (8c) according to the line power supply voltage supplied from the connected exchange. ) Has been switched to any one. Therefore, the reception signal is gain-adjusted by the reception attenuator (4b) with a characteristic determined by one of the selected volume correction characteristic adjustment circuits (8a), (8b) or (8c), and applied to the receiver (7). .

When the transmitter signal is collected by the transmitter (6), the transmitter attenuator (4a) selects one of the selected volume correction characteristic adjusting circuits (8a), (8b) or (8c). ), The gain is adjusted with a characteristic that is determined by, and the sound is output from the transmission / reception volume correction circuit (4). This signal is output to the line through the line controller (3), the diode bridge (2), and the modular (1).

As described above, in this embodiment, the microcomputer
Microcomputer (9) using the A-D conversion input port (9A) of (9)
Since the line power supply voltage is detected and held by, the voltage detection circuit and the holding circuit as in the first and second embodiments are not required,
As a result, the circuit configuration becomes simple and the cost is low.

Embodiment 4 FIG. Embodiment 4 of the present invention will be described below with reference to the drawings. FIG. 5 is a block diagram showing a schematic configuration of this embodiment. In the figure, (1) is a modular jack, (2) is a diode bridge, (3) is a line controller,
(4) is a transmission / reception volume correction circuit, (4a) is a transmission attenuator of this circuit, (4b) is a reception attenuator, (5) is a balance network, (6) is a transmitter, (7) is a receiver, ( 9) is a microcomputer, (9A) is its A / D conversion input port.
The same as Example 3 shown in FIG.

Reference numeral (8) is a volume correction characteristic adjusting circuit for setting different volume correction characteristics in the transmission / reception volume correction circuit (4) by controlling the electronic volume (8A) contained in the electronic volume (8). 8A) is controlled by a switching signal from the microcomputer (9) according to the line power supply voltage to change the resistance value, and constitutes a volume correction characteristic changing means.

Next, the operation will be described. First, before the line is closed, the voltage corresponding to the line power supply voltage applied to the A / D conversion input port (9A) of the microcomputer (9) is 48V of the NTT line or from the private branch exchange. The microcomputer (9) detects whether the medium line power supply voltage of about 36 V or the low power supply voltage of 24 V is detected, and a switching signal corresponding to the detected voltage is held even when the line is closed. The electronic volume (8A) is controlled by this switching signal, and the volume correction characteristic of the characteristic according to the connected line power supply voltage is the volume correction characteristic adjustment circuit.
It is set in the transmission / reception volume correction circuit (4) by (8).

In the call, the line control unit (3) is controlled by the microcomputer (9), and the call can be made when the line is closed. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4). The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. At this time, the electronic volume (8A) is controlled by the switching signal from the microcomputer (9), and the reception attenuator (4b) is connected to the line power supply voltage supplied from the connected exchange by the volume correction characteristic adjustment circuit (8). The volume correction characteristic according to is set. Therefore, the reception signal is gain-adjusted by the reception attenuator (4b) with the characteristics set therein and applied to the receiver (7).

Further, when the transmission signal is collected by the transmission device (6), the transmission attenuator (4a) adjusts the gain with the characteristics set therein, and outputs from the transmission / reception volume correction circuit (4). To be done. This signal is output to the line through the line controller (3), the diode bridge (2), and the modular (1).

As described above, in this embodiment, since the volume correction characteristic set in the transmission / reception volume correction circuit (4) can be changed by the electronic volume (8A), it can be connected to any line of power supply voltage and is always optimum. The gain is adjusted by the characteristic of.

Example 5. Embodiment 5 of the present invention will be described below with reference to the drawings. FIG. 6 is a block diagram showing a schematic configuration of this embodiment. In the figure, (1) is a modular jack, (2) is a diode bridge, (3) is a line controller,
(4) is a transmission / reception volume correction circuit, (4a) is a transmission attenuator of this circuit, (4b) is a reception attenuator, (5) is a balance network, (6) is a transmitter, (7) is a receiver, ( Reference numeral 8) is a volume correction characteristic adjusting circuit, and (8A) is an electronic volume for changing the characteristic of the volume correction characteristic adjusting circuit (8). The above is the same as that of the fourth embodiment shown in FIG.

Reference numeral (13) is a manual operation section for manually inputting to the microcomputer (9). By inputting by this manual operation section, a manual operation section for controlling the electronic volume (8A) of the volume correction characteristic adjusting circuit (8) is provided. Instructed to change the switching signal from the microcomputer (9) and set the volume correction characteristics desired by the user.
Can be set to.

Next, the operation will be described. First, before the line is closed, the voltage corresponding to the line power supply voltage applied to the A / D conversion input port (9A) of the microcomputer (9) is 48V of the NTT line or from the private branch exchange. The microcomputer (9) detects whether the medium line power supply voltage of about 36 V or the low power supply voltage of 24 V is detected by the microcomputer (9), or the switching signal instructed to be changed by the user by the manual operation unit (13) is sent. It is retained even when the line is closed. The electronic volume (8A) is controlled by this switching signal, and the volume correction characteristic adjusting circuit (8) adjusts the volume correction characteristic of the characteristic according to the line power supply voltage to be connected or according to the user's instruction. Set in the correction circuit (4).

In the call, the line control unit (3) is controlled by the microcomputer (9), and the call can be made when the line is closed. The reception signal enters from the modular (1), reaches the balance network (5) through the diode bridge (2) and the line controller (3). Here, it is separated from the transmitted voice and input to the transmitted / received sound volume correction circuit (4). The transmission / reception volume correction circuit (4) includes a reception attenuator (4b) whose gain changes according to line loss. At this time, the electronic volume (8A) is controlled by the switching signal from the microcomputer (9), the reception attenuator (4b) is the volume correction characteristic adjusting circuit (8), the line power supply voltage supplied from the connected exchange, Alternatively, the characteristic is set according to the instruction from the user. Therefore, the reception signal is gain-adjusted by the reception attenuator (4b) with the characteristics set therein and applied to the receiver (7).

When the transmission signal is collected by the transmission device (6), the transmission attenuator (4a) adjusts the gain with the characteristics set therein, and the transmission / reception volume correction circuit (4).
Will be output. This signal is output to the line through the line controller (3), the diode bridge (2), and the modular (1).

As described above, in this embodiment, the volume correction characteristic set in the transmission / reception volume correction circuit (4) is automatically changed by the line power supply voltage supplied from the connected exchange and the user's The volume correction characteristic can also be changed by manual operation. In this embodiment, the control change instruction by the electronic volume (8A) is performed by the user's manual operation, but a plurality of sound volume correction characteristic adjusting circuits (8a) (8b) (8c) as in the third embodiment. The selection of can also be changed by a user's manual operation.

[0046]

As described above, the invention according to claim 1 of the present invention corrects the volume according to the voltage detecting means for detecting the line power supply voltage supplied from the exchange and the detected voltage by the voltage detecting means. Since the volume adjustment characteristic changing means for changing the volume adjustment characteristic set in the transmission / reception volume adjustment circuit by the characteristic adjustment circuit is provided, the optimum volume adjustment characteristic is always set even if the power supply voltage of the connected line is different. There is an effect that it is possible to realize a call that is easy to talk with proper transmission volume, reception volume and sidetone volume.

As described above, in the invention described in claim 2, in the invention described in claim 1, a plurality of sound volume correction characteristic adjusting circuits having different characteristics are provided, and the sound volume correction characteristic varying means comprises: According to the voltage detected by the voltage detecting means, the optimum one of the plurality of volume correction characteristic adjusting circuits is switched to the transmission / reception volume correction circuit to be connected to the volume correction characteristic switching circuit. Therefore, the connection is relatively simple. Even if the power supply voltage of the line to be used is different, the optimum volume correction characteristic is always set, and there is an effect that it is possible to realize a call that is easy to talk with proper transmission volume, reception volume and sidetone volume.

As described above, the invention according to claim 3 is the invention according to claim 1 or 2, wherein a voltage corresponding to the line power supply voltage is applied to the A / D conversion port of the microcomputer as the voltage detecting means. Since it is used, in addition to the above effect, there is an effect that a large number of different voltages can be accurately detected up to the resolution of the AD conversion port without providing a separate voltage detection circuit or holding circuit.

As described above, the invention according to claim 4 is characterized in that, in the invention according to claim 1 or 3, the volume correction characteristic adjusting circuit has a configuration in which the set volume correction characteristic is made variable by an electronic volume. As the correction characteristic varying means, the electronic volume is adjusted in accordance with the voltage detected by the voltage detecting means. Therefore, in addition to the above effects, it is not necessary to provide a plurality of volume correction characteristic adjusting circuits and switching circuits, and the configuration is simple. In addition, there is an effect that the adjustment step of the resistance value of the electronic volume can be accurately adjusted.

As described above, in the invention according to claim 5, in the invention according to any one of claims 1 to 4, the volume correction characteristic set by the volume correction characteristic adjusting circuit can be manually selected. Therefore, in addition to the above effects, not only the automatic adjustment by the line power supply voltage but also the effect that the call can be made at each volume of the transmission, the reception, and the sidetone according to the user's preference.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of the present invention.

FIG. 2 is a characteristic diagram for explaining the operation of the first embodiment.

FIG. 3 is a block diagram showing a schematic configuration of a second embodiment of the present invention.

FIG. 4 is a block diagram showing a schematic configuration of a third embodiment of the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a fourth embodiment of the present invention.

FIG. 6 is a block diagram showing a schematic configuration of a fifth embodiment of the present invention.

FIG. 7 is a block diagram showing a configuration of a conventional telephone device.

[Explanation of symbols]

4, transmission / reception volume correction circuit, 4a transmission attenuator, 4
b receiver attenuator, 6 transmitter, 7 receiver, 8,
8a, 8b, 8c Volume correction characteristic adjusting circuit, 8A Electronic volume (volume correction characteristic changing means), 9 Microcomputer, 9
A A-D conversion input port (voltage detection means) 10,1
0a, 10b voltage detection circuit (voltage detection means), 11
Holding circuit (voltage detection means), 12 Volume correction characteristic switching circuit (volume correction characteristic changing means), 13 Manual operation section.

Claims (5)

[Claims] 1. A telephone device provided with a transmission / reception volume correction circuit for correcting the volume of a handset according to a circuit loss and a volume correction characteristic adjustment circuit for setting the characteristic of the transmission / reception volume correction circuit. And a sound volume correction characteristic for changing the sound volume correction characteristic set in the transmission / reception volume correction circuit by the sound volume correction characteristic adjustment circuit in accordance with the voltage detection means for detecting the line power supply voltage A telephone device having variable means. 2. A plurality of volume correction characteristic adjustment circuits having different characteristics are provided, and a plurality of volume correction characteristic adjustment circuits are provided as volume correction characteristic varying means in accordance with the detection voltage of the voltage detecting means. 2. The telephone device according to claim 1, wherein the optimum one is a volume correction characteristic switching circuit for switching and connecting to the transmission / reception volume correction circuit. 3. The control microcomputer is used as the voltage detecting means by applying a voltage corresponding to the line power supply voltage to its analog-digital (AD) conversion port. 2. The telephone device described in 2. 4. The volume correction characteristic adjusting circuit is configured to change the set volume correction characteristic by an electronic volume, and the volume correction characteristic changing means adjusts the electronic volume according to a detection voltage by a voltage detecting means. The telephone device according to claim 1, wherein the telephone device has a configuration. 5. The telephone device according to claim 1, wherein the volume correction characteristic set by the volume correction characteristic adjusting circuit is selectable by a manual operation.