JPH04299640A - Telephone set system - Google Patents

Abstract

PURPOSE:To adjust decreased sound volume due to attenuation of a voice signal to a proper level at start of talking. CONSTITUTION:The telephone set system is a system in which at least two telephone sets or over are provided to send/receive a voice signal through an analog line and a prescribed level of a reference signal is generated to each of telephone sets A,B at line connection. The system is provided with a reference signal generator 7 outputting the reference signal to an analog line 1, a comparator 11 comparing the reference signal outputted from the reference signal generator 7 with a reference signal sent from an opposite party through the analog line 1 and a CPU 12 controlling the adjustment of the amplification factor of the voice signal sent afterward through the analog line 1 based on an output level of the comparator 11.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephone system using an analog line, and more particularly to a telephone system equipped with a terminal telephone capable of automatically adjusting volume reduction due to attenuation of voice signals.

0002

2. Description of the Related Art In conventional telephones that use analog lines, the side that makes a call (hereinafter referred to as the calling side)
When a person makes a call through the handset after connecting to the line, the voice signal obtained by the handset's microphone is amplified to a certain level and sent to the analog line. On the other hand, on the side receiving the call (hereinafter referred to as the called side), the voice signal received via the analog line is amplified to a certain level by a built-in amplifier and output from the speaker of the handset.

Furthermore, some popular telephones allow the user to adjust the volume of sound emitted from a speaker by operating an amplifier equipped with a volume control.

0004

[Problem to be Solved by the Invention] However, in the former type of telephone, where the degree of amplification is fixed, if the voice signal from the calling party is attenuated during transmission over the analog line, the voice signal from the speaker of the called party's handset becomes weak. The volume becomes low. In particular, when the amount of attenuation of the audio signal is large, the audio from the calling party may drop to such an extent that it cannot be heard by the speaker of the called party.

[0005] Furthermore, in the latter telephone with variable amplification,
The called party controls the volume to determine the volume of the handset's speaker, which has to be adjusted each time a call is made, and there are problems in which the volume can be adjusted by mistake during a call.

The present invention has been made in view of the above circumstances, and its object is to provide a telephone system in which amplification is performed in accordance with the amount of attenuation each time a call is made.

[0007]

[Means for Solving the Problems] In order to solve the above problems, the telephone system of the present invention includes at least two or more telephones that transmit and receive voice signals through analog lines, and each of the telephones has the following: a reference signal generating means for generating a reference signal of a certain level when a line is connected and outputting the reference signal to the analog line; a reference signal output from the reference signal generating means;
Comparing means for comparing with a reference signal sent through the analog line; and control means for adjusting the amplification degree of the audio signal subsequently sent through the analog line based on the output level of the comparing means. The configuration is equipped with the following.

[0008]

[Operation] When a calling signal is sent from the telephone on the calling side through an analog line, the called side detects the arrival of this calling signal and outputs a reference signal from the reference signal generating means.
It is sent to the calling party via an analog line.

[0009] The calling side receives the reference signal sent from the called side, and compares the received reference signal with a reference signal generated by an internally provided reference signal generating means. Compare by. Then, based on the output level of the comparison means, the control means adjusts the degree of amplification of the voice signal of the called side that is subsequently sent through the analog line.

On the other hand, the calling side, after adjusting the amplification degree of the voice signal, sends the reference signal generated by its own reference signal generating means to the called side through an analog line.

[0011] Similarly, the called side receives the reference signal sent from the calling side, and also combines the received reference signal with the reference signal generated by the reference signal generation means provided inside. Compare by means of comparison. Then, based on the output level of this comparison means, the control means:
Adjusts the degree of amplification of the calling side's voice signal that is subsequently sent through the analog line.

For example, when the reference signal from the calling side is attenuated and its level has decreased due to passing through an analog line, the amplification degree of the amplifier is increased to match the level of the reference signal from the called side. Along with this, since the audio signal is also amplified, the problem of the volume of the speaker being reduced due to a drop in the level of the audio signal is avoided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are block diagrams showing the electrical configuration of each terminal telephone in the telephone system according to the present invention.

This telephone system includes a plurality of telephones connected to each other via an analog line 1, and each telephone has the same function.

[0016] In this example, telephone A, which is the calling party,
A case will be described in which a telephone conversation is made between two telephones, with telephone B being the called party.

In FIG. 1, a bridge circuit 2 of a telephone A is connected to an analog line 1 connected to a telephone exchange (not shown).

The output of the bridge circuit 2 is connected to the input of the first amplifier 4 and the input of the second amplifier 5 via the first switch 3, and the output of the second amplifier 5 is It is connected to the input of the first amplifier 4. The output of the first amplifier 4 is connected to a speaker 6a built into the handset 6.

On the other hand, the output of the microphone 6b built into the handset 6 is connected to the second switch 9 via the fourth amplifier 10, and the output of the second switch 9 is connected to the bridge circuit 2. has been done.

Furthermore, the output of the bridge circuit 2 is transmitted to the comparator 1.
1 and a CPU (central processing unit) 12 .

The other input of the comparator 11 is led to one output 7a of the reference signal generator 7 which generates the reference signal Sa at a constant level, and the output of the comparator 11 is connected to the CPU 1.
It is guided by 2. The comparator 11 compares the reference signal Sa from the reference signal generator 7 with the reference signal sent from the other party via the analog line, and determines whether the sent reference signal is generated by the reference signal generator 7 or not. reference signal S
When it is smaller than a, a signal of "0" indicating attenuation is output to the CPU 12, and when it is larger, a signal of "1" is output to the CPU 12.

In addition, the other output 7b of the reference signal generator 7
is transmitted through the third amplifier 8 that amplifies the reference signal Sa,
It is connected to the second switch 9.

Further, the switching control input of the first switch 3 and the switching control input of the second switch 9 are provided by the CPU 12.
switching control signals are output at respective timings.

The first switch 3 receives a switching control signal from the CPU 12 and switches its internal connection to the first amplifier 4 side or the second amplifier 5 side. Further, the second switch 9 receives a switching control signal from the CPU 12 and switches its internal connection to the third amplifier 8 side or the fourth amplifier 10 side.

The configuration of telephone B shown in FIG. 2 is also exactly the same as the configuration of telephone A shown in FIG.

Next, the operation of the telephone system having the above configuration will be explained with reference to the flowchart of telephone A, which is the calling party, shown in FIG. 3, and the flowchart of telephone B, which is the called party, shown in FIG. 4.

In the state of waiting for an incoming call, the second switch 9 of telephone A switches its internal connection to the fourth amplifier 10 side, and the second switch 29 of telephone B switches its internal connection to the fourth amplifier 10 side. Switched to the amp 30 side.

When telephone A calls telephone B in this state, a calling signal from telephone A is sent to telephone B on the called side via analog line 1 (step S
1).

When the telephone B on the called side detects the incoming call signal and confirms that the line is connected by the CPU 32 (step S11), the CPU 32 sends a switching control signal to the second switch 29. Then, the connection of the second switch 29 is switched to the third amplifier 28 side for a short time (step S12).

As a result, the reference signal Sb output from the reference signal generator 27 is amplified by the third amplifier 28, and the second switch 29, the bridge circuit 22, and the analog line 1
is sent to the calling party's telephone A via (step S1
3).

After sending out the reference signal Sb for a short time in this manner, the CPU 32 again sends out a switching control signal to the second switch 29 to change the connection of the second switch 29 back to the fourth amplifier 30. Switch to the side. (Step S14
).

On the other hand, the reference signal Sb sent from the telephone B side is guided to the comparator 11 via the bridge circuit 2 on the telephone A side (step S2). The comparator 11 is supplied with a reference signal Sa from the internal reference signal generator 7, and the comparator 11 compares the levels of both reference signals Sa and Sb (step S3).

At this time, the reference signal Sb is connected to the analog line 1.
If the reference signal S is attenuated by passing through
Since a is larger than the reference signal Sb, the comparator 11 outputs a signal of "0" indicating attenuation. Upon receiving this "0" signal, the CPU 12 sends a switching control signal to the first switch 3, and switches the connection of the first switch 3 to the second amplifier 5 side (step S4). As a result, the voice signal input from the telephone B on the called side is amplified by the second amplifier 5, further amplified by the first amplifier 4, and then supplied to the speaker 6a.

In addition, in the comparison in step S3, if the reference signal Sb is greater than the reference signal Sa, the comparator 1
1 outputs a signal of "1". Upon receiving this "1" signal, the CPU 12 sends a switching control signal to the first switch 3, and switches the connection of the first switch 3 to the first amplifier 4 side (step S5). As a result, the voice signal from the telephone B of the called party that is subsequently input is amplified only by the first amplifier 4 without passing through the second amplifier 5, and is supplied to the speaker 6a in normal operation. Become.

After that, the CPU 12 switches the second switch 9
A switching control signal is sent to the amplifier 8, and the connection of the second switch 9 is switched to the third amplifier 8 side for a short time. (Step S6). As a result, the reference signal Sa output from the reference signal generator 7 on the telephone A side is now transmitted to the third amplifier 8.
The signal is amplified by the second switch 9, the bridge circuit 2, and the analog line 1 and sent to the called telephone B (step S7).

After sending the reference signal Sa for a short time in this way, the CPU 12 again sends a switching control signal to the second switch 9, and changes the connection of the second switch 9 to the original fourth amplifier 10. (step S8). As a result, the audio signal inputted from the microphone 6b after that is
The signal is amplified by the fourth amplifier 10 and sent to the called telephone B via the second switch 9, the bridge circuit 2, and the analog line 1.
It will be sent to

On the other hand, the reference signal Sa sent from the telephone A side is guided to the comparator 31 via the bridge circuit 22 on the telephone B side (step S15). The comparator 31 is given a reference signal Sb from an internal reference signal generator 27, and the comparator 31 receives both reference signals Sa and Sb.
The levels of are compared (step S16).

At this time, the reference signal Sa is connected to the analog line 1.
If the reference signal S is attenuated by passing through
Since b is larger than the reference signal Sa, the comparator 31 outputs a signal of "0" indicating attenuation. Upon receiving this "0" signal, the CPU 32 sends a switching control signal to the first switch 23, and switches the connection of the first switch 23 to the second amplifier 25 side (step S17). As a result, the voice signal from the calling side telephone A that is subsequently input is amplified by the second amplifier 25, and is further amplified by the first amplifier 25.
After being amplified by the amplifier 24, the signal is supplied to the speaker 26a.

Furthermore, in the comparison at step S16,
When the reference signal Sa is larger than the reference signal Sb,
Since the reference signal Sa is not attenuated much, the comparator 31 outputs a signal of "1". The CPU 32 is
Upon receiving this "1" signal, a switching control signal is sent to the first switch 23, and the connection of the first switch 23 is changed to the first switch.
(step S18). As a result, the voice signal inputted from the telephone A on the calling side is amplified only by the first amplifier 24 without passing through the second amplifier 25, and is supplied to the speaker 26a in the normal operation. Become.

[0040] That is, when a telephone call is made between the terminal telephones of this telephone system, each telephone transmits a reference signal to the other party prior to the telephone call, and each telephone subsequently transmits a reference signal based on this reference signal. It is designed to adjust the amplification degree of the audio signal. As a result, analog line 1
Even if the audio signal sent through the device is attenuated, you can always hear the other party's voice at a stable volume.

In the above embodiment, each of the telephones A and B is provided with one comparator 11, 31, and one each with second amplifiers 5, 25 for increasing the amplification.
Although the configuration is such that the amplification degree is switched in two stages, by providing a plurality of comparators and amplifiers in correspondence with each other, it is possible to switch and adjust the amplification degree in multiple stages.

[0042]

Effects of the Invention In the telephone system of the present invention, when a call is made between terminal telephones, each sends a reference signal to the other party prior to the call, and based on this reference signal, the subsequent voice signal is transmitted. Since the configuration is configured to adjust the amplification degree of the audio signal, even if the audio signal is attenuated while being sent through the analog line, the amplification degree can be increased by an amount commensurate with the attenuation, thereby reducing the volume of the audio signal. This has the effect that users can always talk to each other at an appropriate volume without any noise.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of one telephone that constitutes the telephone system of the present invention.

FIG. 2 is a block diagram showing the electrical configuration of another telephone that constitutes the telephone system of the present invention.

FIG. 3 is a flowchart of the calling side telephone shown in FIG. 1;

FIG. 4 is a flowchart of the called telephone shown in FIG. 2;

[Explanation of symbols]

1 Analog line 2, 22 Bridge circuit 6,26 Handset 7, 27 Reference signal generator 11, 31 Comparator 12,32 CPU

Claims (1)

[Claims] 1. A telephone system comprising at least two telephones that transmit and receive voice signals through an analog line, in which a reference signal of a certain level is generated to each of the telephones when the line is connected, and the reference signal is transmitted to each of the telephones. a reference signal generating means for outputting to the analog line; a comparing means for comparing the reference signal output from the reference signal generating means with a reference signal sent through the analog line; and an output level of the comparing means. a control means for adjusting the degree of amplification of a voice signal subsequently sent through the analog line based on the above.