JPH0773301B2 - Communication terminal - Google Patents

Description

The present invention relates to a communication terminal connected to a public line such as a telephone and a facsimile machine.

[Prior Art] For example, when performing image communication using a facsimile device,
Generally, after setting the original on the image reading unit, the handset is hooked off. Then, since the line is connected between the facsimile machine and the exchange, the telephone number of the other party is input. By doing so, the line is connected between the facsimile machine and the other party via the exchange. Then, the image of the original is read by the image reading unit, converted into a video signal, and transmitted to the other party through the exchange and the line.

By the way, the terminal is connected to the exchange by off-hooking the handset. At this time, the exchange sends a 400 Hz dial tone periodically until a telephone number is input. That is, when the user on the terminal side hears this dial tone from the speaker, it can be confirmed that the line has been normally connected to the exchange, and the operation can be shifted to the input of the telephone number.

[Problems to be Solved by the Invention] However, conventionally, an amplifier used for a speaker of a telephone, a facsimile machine or the like has a smooth frequency characteristic over the entire range. For this reason, a low-frequency range (400H
There was a problem that it was difficult to check the dial tone because it became difficult to play the dial tone of z).

Therefore, according to the present invention, by amplifying at least the low frequency range to which the dial tone belongs while receiving the dial tone, the dial tone can be reliably reproduced even with a speaker with a low volume. The present invention aims to provide a communication terminal capable of easily determining the connection state of the communication terminal.

[Means for Solving the Problems] A communication terminal according to the present invention includes a speaker, an amplification unit for adjusting the volume of the speaker, a handset, an off-hook detection unit for detecting an off-hook of the handset, and a telephone number input unit. And a telephone number input detecting means for detecting a telephone number input from the input section, and a period from when the off-hook detecting means detects the off-hook of the handset to when the telephone number input detecting means detects the input of the telephone number, An amplification degree control means for increasing the amplification degree of the amplification section at least only in the low frequency range is provided.

[Operation] By taking such a means, since the amplification unit of the speaker amplifies at least only the low frequency range from the time the off-hook of the handset is performed to the time the telephone number is input, reception during that time is performed. Low frequency range (400H
The dial tone of z) will be reliably played even if the speaker has a low volume.

[Embodiment] An embodiment in which the present invention is applied to a facsimile apparatus will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the schematic arrangement of a facsimile apparatus according to this embodiment. As shown in the figure, the public line 1 is connected to a telephone circuit 3 for transmitting / receiving an audio signal and a modem 4 for transmitting / receiving a video signal via a line switching unit 2. A handset 5 is directly connected to the telephone circuit 3, and a speaker 6 is provided with an amplifier 7 for adjusting the volume.
Connected through.

On the other hand, the telephone circuit 3 and the modem 4 are each connected via a bus line 8 to a CPU (central processing unit) 9 which functions as a control unit main body of the facsimile apparatus.
Also, ROM 10 in which program data, character generator data, etc. are stored, RAM 11 having a memory for temporarily storing video signals, clock circuit 12, dial keys for inputting telephone numbers, transmission keys, cancel keys, etc. A keyboard circuit 14 for receiving a key signal from a keyboard 13 provided with various keys, a display control circuit 16 for driving and controlling a display 15 to display a telephone number, a time, various messages and the like keyed in, a video A printer control circuit 18, which converts the signal into image data and outputs it to the printer 17,
An image input circuit 20 for converting the image data of the original read by the image sensor 19 into a video signal, an output port 21, and the like are connected to the CPU 9 via the bus line 8.

The output port 21 outputs an amplified signal S1 to the amplification unit 7 and a switching signal to the line switching unit 2 according to a command from the CPU 9. The line switching unit 2 switches the public line 1 to the telephone circuit side 3 or the modem side 4 according to the switching signal S2.

FIG. 2 is a circuit diagram showing a specific configuration of the amplification section 7. A speaker 8 is connected to an input terminal 71 to which an analog signal is input from the telephone circuit 3 via a normally closed switch 72 and an amplifier 73 in series. Also, the above normally closed switch
72 in parallel with normally open switch 74 and low frequency booster 75
A series circuit consisting of is connected. Here, the amplifier 73 is for amplifying smoothly over the entire frequency range of the analog signal, and is the same as that used as a speaker amplifier in a conventional facsimile apparatus or the like. The low-frequency booster 75 amplifies only the low-frequency region centered around 400 Hz of the analog signal. The normally closed switch 72 and the normally open switch 74 are connected to the output port 21.
Are opened and closed in conjunction with each other in accordance with the amplified signal S1 given by the switch, the normally closed switch 72 is opened and the normally open switch 74 is closed when the amplified signal S1 is on, and the normally closed switch 72 is closed when the amplified signal S1 is off. The normally open switch 74 is opened.

Then, the CPU 9 is program-controlled so as to execute the processing shown in FIG. 3 when detecting the off-hook of the handset 5. That is, in response to the detection of off-hook, an off-hook signal is output from the telephone circuit 3 to the public line 1 via the line switching unit 2 to inquire of the switch whether or not the line 1 can be used. At the same time, the amplified signal S1 is turned on and output from the output port 21 to the amplification unit 7. Then keyboard 13
When it is detected that the first digit of the telephone number has been input by the dial key of, the amplified signal S1 is immediately turned off and the subsequent normal processing is performed.

In this embodiment having such a configuration, the public line 1 is connected to the normal telephone circuit 3. Further, the normally closed switch 72 and the normally open switch 74 of the amplification section 7 are closed. In this state, when the user of the facsimile apparatus transmits the image data of the original document to the other party, the user first sets the original document on the image reading unit provided with the image sensor 19. Then, the handset 5 is taken off-hook.
Then, as shown in FIG. 3, an off-hook signal is output from the telephone circuit 3 to the line 1 to inquire of the exchange about whether or not the line can be used, and the amplified signal S1 from the output port 21 is turned on. 7, the normally closed switch 72 is opened and the normally open switch 74 is closed. As a result, the analog signal input to the input terminal 71 is given to the speaker 6 via the normally open switch 74, the low frequency booster 75 and the amplifier 73, and as shown by the solid line A in FIG. The amplification factor in the low frequency band around 400 Hz of the signal is higher than that in other frequency bands. Therefore, when the use of the line connecting the exchange and the facsimile machine is permitted, the exchange sends a dial tone of 400 Hz, which is reproduced by the speaker 6 with high accuracy.

Therefore, the user can confirm that the line 1 is normally connected by listening to the dial tone reproduced by the speaker 6, and therefore, the dial number of the keyboard 13 is used to key in the telephone number of the other party. Then, when the first digit of the telephone number is input, the amplified signal S1 is turned off, and accordingly, the normally closed switch 72 and the normally open switch 74 of the amplification section 7 are opened. As a result, the analog signal input to the input terminal 71 is given to the speaker 6 via the normally closed switch 72 and the amplifier 73, so that the operating frequency of the analog signal as shown by the broken line B in FIG. 400
Amplification is almost smooth over the entire range.

After that, when the line is connected to the other side via the exchange, the switching signal S2 is output from the output port 21 and the line 1 is connected to the modem 4 by the line switching unit 2. Then, the image reading of the original by the image sensor 19 is started,
The read image data is converted into a video signal and transmitted from the modem 4 to the other party via the line switching unit 2. After the transmission is completed, the switching signal S2 is output again and the telephone circuit 3
The line 1 is connected to and the incoming call becomes possible.

As described above, according to the present embodiment, the amplification unit for adjusting the volume of the speaker 6 during the period when the dial tone is sent from the exchange, that is, after the handset 5 is off-hook until the telephone number is input. Since the amplification factor of 7 is increased only in the low frequency range including the frequency of the dial tone, the dial tone can be reproduced with high accuracy by the speaker 6. Therefore, the loud speaker 6
Even in this case, the user of the facsimile apparatus can surely hear the dial tone and can easily confirm the connection state of the line. In other words, as a speaker used in such a facsimile apparatus, a small one with a low volume can be applied, so that the apparatus can be downsized.

In the above embodiment, the low-frequency booster 75 is used to increase the amplification degree of the amplification unit 7 only in the low-frequency including the dial tone frequency. However, the present invention is not limited to this, and for example, As shown in FIG. 5, an amplifier 76 that outputs a variable gain may be used, and the gain of the amplifier 76 may be increased between the time when the handset 5 is off-hook and the time when the telephone number is input. In this case, the amplification factor when the gain is increased rises over the entire frequency range as shown by the chain line C in FIG. 4, but the reproduction accuracy of the dial tone is improved as in the above embodiment. Absent. Also, as shown in FIG. 6, two amplifiers 77 and 78 are connected in series, and the switch 79 is opened between the time the handset 5 is off-hook and the telephone number is input to use the initial amplifier 77. Thus, it is possible to increase the amplification degree in the entire frequency range. In this case, the amplification factor when the first stage amplifier is used is also shown by the one-dot chain line C in FIG.

Further, it goes without saying that the present invention is not limited to the facsimile machine and can be applied to a communication terminal such as a telephone. Of course, various modifications can be made without departing from the scope of the present invention.

[Effect of the Invention] As described in detail above, according to the present invention, a speaker with a low volume is used by amplifying at least the low frequency range to which the dial tone belongs while receiving the dial tone. Even in this case, it is possible to provide a communication terminal capable of reliably reproducing the dial tone and easily determining the connection state of the line.

[Brief description of drawings]

1 to 4 are views showing an embodiment in which the present invention is applied to a facsimile machine. FIG. 1 is a block diagram showing a schematic structure of the facsimile machine, and FIG. 2 is a concrete structure of an amplifying section. , FIG. 3 is a flow chart showing the main processing of the CPU, FIG. 4 is a characteristic diagram showing an example of frequency characteristics of the amplification section, and FIGS. 5 and 6 are circuit diagrams showing modified examples of the amplification section. Is. 1 ... public line, 3 ... telephone circuit, 5 ... handset, 6 ... speaker, 7 ... amplifier, 9 ... CPU, 13 ...
… Keyboard, 73,76,77,78 …… Amplifier, 75 …… Low-range booster.

Claims (1)

[Claims] 1. A communication terminal connected to a public line, a speaker, an amplification section for adjusting the volume of the speaker, a handset, an off-hook detection means for detecting an off-hook of the handset, and a telephone number input section. , A telephone number input detecting means for detecting a telephone number input from the input section, and from the off-hook detecting means detecting an off-hook of the handset until the telephone number input detecting means detecting an input of a telephone number. A communication terminal, comprising: an amplification degree control means for increasing the amplification degree of the amplification section at least only in a low frequency range.