JPH06178032A - Facsimile equipment - Google Patents

Abstract

(57) [Abstract] [Purpose] When a telephone call display sound signal is received during image data reception in a facsimile machine connected to one communication line that can be switched to a telephone line or a facsimile line by switching. Allows to detect the signal. [Structure] A modem 2, a decoding unit 3, a printing unit 4, a bandpass filter 5, an incoming call display sound detection unit 6, and a display unit 7 are provided,
The bandpass filter 5 and the incoming call display sound detection unit 6 detect the incoming call display sound signal input from the line 1 during the reception of the image data, and the display unit 7 displays the signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile device connected to one communication line which can be a telephone line or a facsimile line by switching, not a facsimile device connected to a facsimile line. Yes, in more detail, while receiving a facsimile using the communication line, when the incoming call display sound for the telephone connected to the communication line by switching is sent from the exchange side, the incoming call display sound is detected. The present invention also relates to a facsimile apparatus in which reception of such an incoming call indication sound does not adversely affect facsimile communication.

[0002]

2. Description of the Related Art The spread of facsimile machines has been remarkable not only in offices but also in homes for several years. A facsimile device is a transmission device that can send and receive image information such as documents and drawings to and from a remote place using a line.

Regarding the communication procedure and the like, CCITT
(International Telegraph and Telephone Advisory Committee) Recommendation 30 and TTC (Telephone and Telephone Technical Committee) standard JT-T30.

In the conventional facsimile machine, a communication line dedicated to the facsimile machine is drawn separately from the communication line of the telephone.
Although the book communication line was exclusively used for facsimiles, in recent years, it has become common to use one communication line by physically switching between the facsimile device and the telephone.

When a communication line is used in a facsimile machine, the image information to be transmitted and received is transmitted and received using the frequency band used for telephones in the communication line as it is. Therefore, while receiving image information as a facsimile, another signal (for example, an incoming call display sound that informs the other party when the other party receives an incoming call while the telephone is busy) on the communication line. Etc.), the signal becomes noise for the image information and the image information cannot be received correctly. As a method for avoiding this, a method as proposed in Japanese Patent Laid-Open No. 4-126455 is known.

[0006]

When a telephone call is received from a person other than the person who is currently talking while the telephone is talking on the telephone, the exchange sends an incoming call display tone to the called side, and the incoming call is received. A telephone service that allows the party to know the fact by listening to the incoming call tone and press the hook switch on the telephone to switch the person who is talking from the person who is currently speaking to the person who is newly calling (hereinafter, called This is called an incoming call sound service) is provided.

In the above-mentioned prior art, when one telephone is used by switching between a telephone and a facsimile machine, the facsimile machine is used when the user is qualified to receive the above-mentioned incoming call display tone service. When the incoming call sound is received on the communication line during reception, information (incoming call sound signal) different from the image information will be sent together to the same communication line to which the image information is sent.
It interferes and cannot correctly receive the image information that should have been sent.

Therefore, in the above-mentioned conventional technique, only the necessary image signal is taken out by the filter and received. However, even if an incoming call display sound comes in on the communication line during facsimile reception, the user recognizes that fact. There was a problem that I could not do it. That is, even if the user is receiving a facsimile, if the incoming call tone is heard on the communication line, the user stops the facsimile reception (I will have to resend it later) and communicates to important telephone communication. Even if you want to switch, there was a problem that you could not recognize the incoming call display sound.

Further, in the prior art, it is preferable that the frequency bands of the image signal and the incoming display sound signal do not overlap, but the CCI
V. of the TT standard. In the case where the frequency bands of the two overlap with each other, as in the case of the facsimile image signal of No. 29, there is a problem that the above-mentioned conventional technique cannot be applied because it is impossible to extract only the necessary image signal by the filter.

Therefore, it is an object of the present invention to allow a user of a facsimile device to receive another external signal from the same communication line for the purpose of providing a specific service while receiving the facsimile, such as the above-mentioned incoming call display tone service. If there is a
When the external signal comes in, the external signal is received and detected, and the user is notified so that the service can be received. Also, by the external signal being sent, the facsimile image information being received is changed. It is an object of the present invention to provide a facsimile machine which is not adversely affected.

[0011]

SUMMARY OF THE INVENTION In the present invention, the above object is to provide a function of transmitting and receiving facsimile image information by using one communication line which can be a telephone line or a facsimile line by switching as a facsimile line. In a provided facsimile device, a receiving means capable of distinguishing and receiving a specific signal different from the facsimile image signal together with the facsimile image signal through the communication line, and transmission / reception via the facsimile line In order to prevent the image signal to be overlapped with the specific signal in terms of frequency, a frequency modulator that converts (shifts) the frequency band of the image signal, and returns it to the original frequency (shifts in reverse). And a frequency demodulation unit.

[0012]

By providing the facsimile device with the receiving means for receiving the distinction, when a specific signal different from the image information is input from the communication line during the facsimile reception,
The image information and the specific signal thereof are received separately, and the user is notified by sound or image that the specific signal has arrived.

The frequency modulation section shifts the frequency of the image information signal during facsimile transmission to a frequency band that does not overlap the specific signal, and the frequency demodulation section
Since the frequency band of the image information signal received at the time of facsimile reception is returned to the original frequency band, the facsimile image information can be communicated without being affected by the specific signal.

[0014]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a main part of a facsimile apparatus as an embodiment of the present invention. In the figure,
A procedure control unit and a line control unit (so-called NCU: Network Control) which are indispensable for a facsimile machine.
Unit) and the like are not shown because they are not directly related to the present invention.

In FIG. 1, 1 is a communication line for transmission,
2 is a modem for receiving image information sent from the facsimile machine of the other party, 3 is a decoding unit for decoding the received image information (data), 4 is a printing unit for printing the decoded data, and 5 is a book One of the important elements in the invention is a bandpass filter (which may be a lowpass filter) capable of removing a frequency band other than the frequency band of the signal in order to detect the incoming display sound signal as a specific signal. is there.

Reference numeral 6 denotes an incoming call display sound detecting section for detecting whether the signal passed through the band pass filter 5 is an incoming call display sound signal,
Reference numeral 7 denotes a display unit for notifying the user by sounding an alarm when an incoming call display sound is heard.

FIG. 2 is a characteristic diagram showing an example of the amplitude / frequency characteristic of the bandpass filter 5 in FIG. That is, it will be understood that the bandpass filter 5 has a characteristic of passing a signal in the frequency range of about 100 Hz centering around 400 Hz.

FIG. 3 is an explanatory diagram showing the signal specifications of the incoming call display sound. That is, the incoming call indication sound is initially 400
A signal obtained by modulating Hz with a signal of 16 Hz continues for 0.5 seconds,
0 to 4 seconds after that, a signal of 400 Hz continues twice for 0.05 seconds at intervals of 0.45 seconds.
This 400 Hz signal is repeated every 4 seconds, and the calling side disconnects the line, or the called side switches the line to the new one by hooking the telephone, etc.
It is repeated until any operation is performed.

The circuit operation of FIG. 1 will be described below with reference to FIGS.

First, in FIG. 1, a facsimile image data signal entered from the communication line 1 is received by the modem 2, then decoded by the decoding unit 3 and printed by the printing unit 4. At the same time, the signal input from the communication line 1 is also sent to the parts (5, 6, 7) that perform the operation of detecting the incoming call display sound, and the bandpass filter 5 first causes the signal of only the frequency band shown in FIG. Is picked up, and the incoming call display sound signal detection section 6 determines whether or not it is the incoming call display sound signal. If it is the incoming call display sound signal, it is detected.

When the incoming call display sound signal is detected by the incoming call display sound signal detection unit 6, an alarm or the like is output on the display unit 7, whereby the user located in the vicinity receives the incoming call display sound. You can know that you entered.

The mechanism of detecting the incoming call display sound signal in the incoming call display sound signal detecting section 6 will be described below. The detection when the incoming call display sound signal enters the communication line 1 is performed by detecting the incoming call display sound signal specifications shown in FIG.
It is detected by utilizing the periodicity of the Hz signal.

The image information signal of the facsimile coming from the communication line 1 usually contains a signal having the same periodicity as that of the incoming call display sound in the frequency band portion shown in FIG. Almost never. Therefore, communication line 1
As a signal that has passed through the band pass filter 5 with a signal that has entered from the
Once, when there is a signal that repeats every 4 seconds, it can be determined that the signal is an incoming call display sound signal.

This completes the description of the embodiment shown in FIG.

Next, FIG. 4 is a block diagram showing still another main part of the facsimile apparatus as one embodiment of the present invention. That is, when an incoming call indicator sound is detected during facsimile reception, the communication line is called from the existing facsimile line in order to interrupt the existing facsimile reception and receive a new incoming call. The circuit part which performs the switching operation which switches to a line is shown.

In FIG. 4, the same parts as those in FIG. 1 are designated by the same reference numerals. In addition, 41 is a hook detection unit, 42 is a hook switch, 43 is a switch for switching the connection of the communication line between the facsimile side and the telephone side, 44 is an incoming call display sound detected from the communication line,
A line switching control unit for switching lines, and 45 is a telephone.

First, during facsimile communication, the switch 43
Is set to the a side and the communication line 1 is connected to the facsimile side (2 to 7). When an incoming call display sound is detected by the detection unit 6 during facsimile reception, the display unit 7 sounds an alarm to notify the user.

When the user in the vicinity knows that the incoming call display sound has been detected, he picks up the handset of the telephone 45. Then, the hook detection unit 41 detects the off-hook of the telephone 45 (close of the hook switch 42) and notifies the line switching control unit 44 of this. Then, the line switching control unit 44 switches the switch 43 from the side a to the side b until then to interrupt the reception of the facsimile image data and switch the communication line 1 to the telephone side.

Furthermore, in order to receive the incoming call display sound service, the user once hooks the telephone (switch 4
By opening and closing 2), it becomes possible for the user to talk with the other party who has made a new call. This makes it convenient to display an incoming call by interrupting facsimile reception (you can talk about the situation and resend the facsimile image information later) when an important call is received even if you are receiving a facsimile. Sound service will be available.

FIG. 5 is a block diagram showing a main part of an image data transmitting section of a facsimile apparatus as another embodiment of the present invention. In the figure, parts such as a procedure control unit and a line control unit of the facsimile apparatus are not shown because they are not directly related to the present invention. The present embodiment shows an embodiment in which the frequency band of the facsimile signal is converted in advance so as not to overlap with the incoming call display sound and transmitted.

When receiving the incoming call display sound service, the facsimile communication being received is interrupted. Therefore, the incoming call display sound may interfere with the facsimile image data being communicated. , It is not necessarily decided to receive the ringtone service, so
Even if there is an incoming call indication sound, when it is ignored and the facsimile communication is to be received to the end, it is not enough that the facsimile image data is disturbed by the incoming call indication sound. Therefore, the present embodiment is effective in such a case.

In FIG. 5, reference numeral 51 is a reading section for a transmission original formed of a CCD or a contact sensor, 52 is a binarization processing section for binarizing the read image data, and 53 is a binarized image. An encoding unit for encoding data into MH code or MR code, 54 is a modem for transmitting encoded image data, 55 is frequency modulation for modulating the frequency of the image data signal to be transmitted and shifting the frequency band. Division 5,
6 is a line.

With respect to the facsimile apparatus shown in FIG. 5, the following will be performed on the facsimile transmission side so that the image data does not have to be affected by the incoming call display sound signal when the incoming call display sound is received while receiving the facsimile image data. 6, 7, 8, and 9 are operations for shifting and transmitting the frequency band of the facsimile image data signal in advance so that the frequency band of the incoming call display sound signal and the frequency band of the facsimile image data signal do not overlap. Will be described with reference to.

FIG. 6 is a characteristic diagram in which the frequency band of the facsimile image data signal before shifting is shown by a broken line and that after shifting is shown by a solid line. Figure 7 shows CCITT
Recommendation V. It is a characteristic view showing the frequency band in 27ter.

FIG. 8 is a block diagram showing details of the frequency modulator 55 in FIG. FIG. 9 is a characteristic diagram showing a frequency band characteristic obtained when the characteristic shown by the solid line in FIG. 6 is modulated by the modulator 81 shown in FIG.

Returning to FIG. 5, first, the reading unit 51 reads the facsimile image data, and the binarization processing unit 52 binarizes the read data. The binarized image data is sent to the encoding unit 53 and encoded. The encoded image data is sent to the modem 54 and modulated according to a predetermined standard (for example, CCITT recommendation V.29 or V.27ter).

Here, for example, the standard is V. In the case of 29, the frequency band is (about 30
0 Hz to 3.1 kHz), and as it is,
Since it overlaps with the frequency band of the incoming call display sound shown in (3), the incoming call display sound cannot be correctly detected upon reception, and the facsimile image data is also disturbed.

Therefore, in such a case, the frequency modulator 55 shown in FIG. From the frequency band (characteristic of the broken line in FIG. 6) of the image data signal at the time of transmission according to the standard of 29, the frequency band characteristic (about 500 Hz to
The frequency band is converted to (3.3 kHz) and then sent to the line 56.

V. According to the standard of 27 ter, the V.27 shown in FIG. As can be seen from the frequency band characteristic of 27ter, since it does not overlap with the frequency band of the incoming call display sound signal (FIG. 2), it is not necessary to perform any particular modulation and there is no problem in transmitting it as it is.

FIG. 8 is a block diagram showing the details of the frequency modulator 55 of FIG. 5, as already described, where 81 is a modulator for modulating the transmitted signal, and 82 is the upper side of the modulated signal. It is a low-pass filter for removing the wave band (a in FIG. 9). Note that FIG. 9 is a characteristic diagram showing frequency band characteristics obtained by modulation by the modulator 81.

In FIG. 5, the image data signal sent from the modem 54 is modulated by the modulator 81 at 3.6 kHz, and becomes a signal having the characteristics (a, b) shown by the solid line portion in FIG. Only the lower sideband of FIG. 9B is extracted by the filter 82 and transmitted. In this way, since it does not overlap with the frequency band of the incoming call display sound, it is not necessary to cause mutual interference.

FIG. 10 is a receiving section of a facsimile apparatus for receiving the image data signal transmitted by shifting (shifting) the frequency band in the facsimile transmitting section of FIG. 5 and detecting whether or not an incoming call display sound is received. It is a block diagram showing.

In FIG. 10, the same parts as those in FIG. 4 are designated by the same reference numerals. In addition, 101 is a high-pass filter that removes the frequency band of the incoming display sound signal,
Reference numeral 102 is a frequency demodulation unit for returning the image data signal input from the line to the original frequency band, 103 is a facsimile reception unit showing a portion related to the facsimile reception unit until receiving and printing the facsimile image data, and 104 is an incoming call display. It is an incoming call display sound detection unit showing a portion related to sound detection.

FIG. 11 is a block diagram showing details of the frequency demodulation unit 102 in the facsimile receiving unit 103 in FIG. In FIG. 11, 111 is a demodulator that restores the received image data signal to the original frequency band, and 112 is the upper sideband signal of the demodulated image data signal (a in FIG. 12).
Is a low-pass filter for removing the.

FIG. 12 is a characteristic diagram showing the frequency band of the image data signal demodulated by the demodulator 111 of FIG. Hereinafter, the circuit operation of FIG. 10 will be described with reference to FIGS. 11 and 12.

In the facsimile receiving section of FIG. 10, the frequency band-shifted facsimile image data signal passes from the line 1 to the facsimile receiving side (a side) through the switch 43 and passes through the facsimile receiving section 1
03 and the incoming call display sound detection unit 104.

The image data signal received in the facsimile receiver 103 is filtered by the filter 101 and the frequency demodulator 102.
At, the frequency band is returned to the original frequency band and the reception process is performed. The incoming call display sound detection unit 104 detects the incoming call display sound by performing the same operation as in the case of the embodiment shown in FIG. 4, and in that case, the line can be switched to the telephone set 45.

FIG. 13 is a block diagram showing still another embodiment of the present invention. In case the incoming call display sound signal comes in during facsimile communication, facsimile image data communication is CCITT standard V.V. 27ter (a standard in which the frequency band of the image data signal does not overlap with that of the incoming call sound signal) is set in the receiving section of the facsimile apparatus.

By turning on this setting switch, a user who is qualified to receive the incoming call display sound service can normally perform the facsimile communication even if the incoming call display sound comes in during the facsimile communication. , It becomes possible to detect that the incoming call display sound is received.

In FIG. 13, the same parts as those in FIGS. 1 and 4 are designated by the same reference numerals. In addition, the reference numeral 131 denotes a facsimile communication of image data signals by V. A setting switch for setting communication according to the 27ter standard.

FIG. 14 shows the frequency band of the incoming call display sound signal and V.V. It is a characteristic view showing a frequency band of a facsimile image data signal according to the 27ter standard. It will be seen that the two frequency bands do not overlap. Less than,
The circuit operation of FIG. 13 will be described with reference to FIG.

In FIG. 13, when the user uses the incoming call display sound service, the setting switch 131 is turned on.
As a result, the image data signal becomes V. Since the communication is performed according to the standard of 27 ter, the image data signal input from the line 1 is transmitted by the modem 2 as V.27. It is processed according to the standard of 27ter. Therefore, even if the incoming call display sound signal comes in from the line, as shown in FIG. 14, the frequency band of the image data signal does not overlap with the frequency band of the incoming call display sound signal.
The incoming call display sound can be detected even during facsimile communication.

In the embodiments shown in FIGS. 4, 10 and 13, when an incoming call display sound is detected during facsimile communication and the telephone is picked up, hooking is automatically performed so that the line is switched to the telephone side. However, it doesn't matter if the phone is taken or not switched.

FIG. 15 is a block diagram showing again the overall construction of the facsimile apparatus as an embodiment of the present invention. In the figure, reference numeral 1500 is a telephone line, 1501 is a telephone attached to the outside of the facsimile apparatus, and 150 is a telephone.
2 is a network control unit (NCU: Network) that performs line control, etc.
ork Control Unit).

In addition, 1503 is a high-pass filter for removing the incoming call display sound, 1504 is a modem, 1505 is a telephone control unit for controlling the built-in telephone, 1506 is the built-in telephone handset, and 1507 is the incoming call display signal. A band-pass filter (may be a low-pass filter) for removing signals other than the above, 1508 is an incoming call display sound detection unit for detecting the incoming call display sound signal, and 1509 is an arithmetic processing unit (CPU) for controlling the entire facsimile apparatus.

Reference numeral 1510 is a ROM (read only memory) for storing software for operating the CPU 1509, 1511 is a RAM (random access memory) used as a work area of the CPU 1509, 1512.
Is a print control unit for controlling print output, 1513 is a print head, 1514 is a reading control unit for controlling reading processing, 1
A reading sensor 515 is composed of a CCD image sensor, a contact sensor, or the like.

Reference numeral 1516 denotes an encoding unit which encodes or decodes the read image data, and can be constituted by hardware, software, or both of them.
Reference numeral 1517 denotes a display unit for displaying a message to the user using a liquid crystal screen or the like for confirming the operating status of the facsimile apparatus, the destination of communication, explanation of the operating procedure, and 1518 is an operation section for operating the entire facsimile apparatus, which is a numeric keypad of the telephone. It is composed of buttons and the like installed in the facsimile machine. Reference numeral 1519 is a system bus including a data bus and an address bus.

The operation in FIG. 15 is basically the same as that described so far, but in this embodiment, the entire CP
It is controlled by U1509. Then, by providing a switch or button on the operation unit 1518, the user who is using the incoming call display sound service knows that the incoming call display sound comes in during image data reception by pressing the switch or button. Therefore, it becomes possible to switch the line to enable a call, and to receive the incoming call display sound without being affected by the incoming call sound.

The display unit 7 in the embodiment shown in FIGS. 1 and 4 is designed to emit an alarm sound to notify the user when an incoming call arrives. Instead of the alarm sound, a display such as a liquid crystal display indicates that. Is displayed or L
A lamp such as an ED may be turned on (blinking). Also, the bell of the telephone may be rung. FIG. 16 shows an embodiment in which a display sound is detected during facsimile reception and the bell of the telephone is set to ring.

In FIG. 16, the same parts as those in FIG. 4 are designated by the same reference numerals. In addition, 161 is a bell signal transmission unit that forms a bell. In this embodiment, when the incoming call display sound detection section 6 detects the incoming call display sound during facsimile reception, the bell signal sounding section 161 generates a telephone call signal (for example, a 16 Hz intermittent sound), and the switch 42 is operated. Ring the bell of the telephone 45. The user can confirm the incoming call by ringing the bell of the telephone 45. The subsequent operation is similar to that described above.

[0062]

According to the present invention, even if a user who is qualified to receive the incoming call display sound service receives a call during facsimile communication, the user can recognize the incoming call display sound, which is important. Even if a simple call is received during facsimile communication, you will not be missed. Also,
Since the incoming call display sound signal is not mixed with the image data signal, there is an advantage that the facsimile communication error due to the incoming call display sound signal can be prevented and the line usage cost can be reduced accordingly.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main part of a facsimile apparatus as an embodiment of the present invention.

FIG. 2 is a characteristic diagram showing an example of amplitude / frequency characteristics of the bandpass filter 5 in FIG.

FIG. 3 is an explanatory diagram showing signal specifications of an incoming call display sound.

FIG. 4 is a block diagram showing still another main part of the facsimile apparatus as one embodiment of the present invention.

FIG. 5 is a block diagram showing a main part of an image data transmitting section of a facsimile apparatus as another embodiment of the present invention.

FIG. 6 is a characteristic diagram showing a frequency band of a facsimile image data signal before shifting by a broken line and a frequency band after shifting by a solid line.

FIG. 7: CCITT Recommendation V. It is a characteristic view showing the frequency band in 27ter.

8 is a block diagram showing details of a frequency modulator 55 in FIG.

9 is a modulator 81 shown in FIG. 8 with characteristics shown by a solid line in FIG.
It is a characteristic view showing a frequency band characteristic obtained when modulated by.

10 is a block diagram showing a receiving unit of a facsimile apparatus for receiving an image data signal transmitted by converting (shifting) a frequency band in the facsimile transmitting unit of FIG. 5 and detecting whether or not an incoming call display sound is received. It is a figure.

11 is a block diagram showing details of a frequency demodulation unit 102 in the facsimile reception unit 103 in FIG.

12 is a characteristic diagram showing a frequency band of an image data signal when demodulated by a demodulator 111 in FIG.

FIG. 13 is a block diagram showing still another embodiment of the present invention.

FIG. 14 shows a frequency band of an incoming call display sound signal and V.I. 27t
FIG. 7 is a characteristic diagram showing a frequency band of a facsimile image data signal according to the er standard.

FIG. 15 is a block diagram showing again the overall configuration of a facsimile apparatus as an embodiment of the present invention.

FIG. 16 is a block diagram showing an example in which a display sound is detected during facsimile reception to ring a telephone bell.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Communication line, 2, 54, 1504 ... Modem, 3 ... Decoding section, 4 ... Printing section, 5 ... Bandpass filter, 6 ... Incoming call display sound signal detecting section, 7 ... Display section, 41 ... Hook detecting section,
44 ... Line switching control unit, 45 ... Telephone, 131 ... Setting switch, 161 ... Bell signal sounding unit

Claims (4)

[Claims] 1. A facsimile apparatus having at least a modem for transmitting and receiving an image signal through a line, wherein a specific signal different from the image signal is transmitted through the line while the image signal is being received by the modem. At this time, the facsimile device is provided with a detecting means for receiving and detecting this, and a displaying means for displaying the reception of the specific signal by the detecting means. 2. A facsimile apparatus having at least a modem for transmitting and receiving an image signal through a line, converting a first frequency band signal into another second frequency band signal which does not overlap with a frequency band of a specific signal, or said first frequency band signal. Two
Is provided with a converting means capable of inversely converting the frequency band signal of the first frequency band signal into a first frequency band signal, and at the time of facsimile transmission, the image signal to be transmitted is converted from the first frequency band signal by the converting means. The second frequency band signal is converted and transmitted, and at the time of facsimile reception, the image signal transmitted in the second frequency band signal format is inversely converted into the first frequency band signal by the conversion means. Thus, even if the specific signal is transmitted during facsimile reception, the image signal transmitted in the second frequency band signal format and the specific signal do not overlap in frequency. A facsimile device characterized by the above. 3. The facsimile apparatus according to claim 1, wherein the specific signal is an incoming call display sound signal transmitted from an exchange through a line. 4. A facsimile apparatus having at least a modem for transmitting and receiving an image signal through a line, comprising: setting means for setting an incoming call indication sound detection mode for the modem; and incoming call indication sound provided on the input side of the modem. A filter that blocks the input of the signal in the frequency band of the signal to the modem, and when the incoming call display sound signal is transmitted together with the image signal through the line, the incoming call display sound signal is frequency separated from the image signal. The incoming call display sound detection mode for detecting the incoming call display sound signal when the incoming call display sound signal is detected by the detecting means, and a display means for displaying the fact that the incoming call display sound signal is detected by the detecting means. When set for the modem, the modem is used to transmit and receive image signals in a frequency band that does not overlap with the frequency band of the incoming call display sound signal. V. of the CITT standard A facsimile machine characterized in that an image signal is transmitted and received by a 27ter.