JP2002218196A - Communication terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a communication terminal that can reduce the number of times of fallback so as to reduce the communication charge. SOLUTION: In the case that a facsimile MODEM 10 is used and image data are faxed to a destination facsimile terminal via a public telephone network in an error correction mode(ECM) and a partial page request signal is received for a prescribed number of times (YES in step S27 in Figure 3) and fallback is already executed at processing transmission speed (YES in step S29), a main control section 1 of a facsimile terminal 20 interrupts a communication channel (step S31) and redial waiting is set (step S32). Furthermore, when redial is made after dial waiting as above, the main control section 1 makes a call to a destination communication terminal at a transmission speed of a communication mode lower than the transmission speed before fallback that is a transmission start transmission speed at preceding dial to start facsimile transmission (steps S41-D43 in Figure 4).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication terminal device such as a facsimile device for facsimile transmitting image data to a destination communication terminal device via a communication line in an error correction mode (ECM) using a modem.

[0002]

2. Description of the Related Art In a conventional facsimile apparatus, image data is transmitted by facsimile to a destination facsimile apparatus via a communication line via a communication line using a modem. The transmitting-side facsimile apparatus transmits the training signal to the other party's facsimile apparatus, determines the transmission speed of the transmitting-side modem on the basis that the training signal can be received at a predetermined error rate or more, and performs facsimile communication. ing.

Here, when the quality of the communication line is poor, the transmission speed of the modem is reduced one step at a time (this is called fallback). It is configured to repeat fallback. For example, the ITU-T recommendation specifies as follows. The V.S. In 34 modes, 33.6 kbps,
31.2 kbps, 28.8 kbps, 26.4 kbp
s, fallback in the order of 16.8 kbps. Then, for example, V.I. 14.4 kbps, 12 in 17 mode
After fallback in the order of kbps, In the 29 mode, fallback is performed in the order of 9600 bps and 7200 bps. 4800bp in 27ter mode
s, fallback in order of 2400 bps.

[0004]

Particularly, in the case where image data is transmitted by facsimile to a destination communication terminal device via a communication line in an error correction mode (ECM), a partial page request signal (PPR signal) is transmitted by four bits. Fallback occurs when receiving data twice, but in conventional facsimile communication, fallback is based on the final transmission speed of the modem (2.4 kbp).
s), there is a problem that the communication time becomes longer and the communication fee becomes higher. In particular, in a high-speed modem having a maximum transmission speed of 33.6 kbps, the number of fallbacks becomes extremely large, and the accompanying communication time becomes extremely long, resulting in high communication charges. In addition,
The communication line used changes every time a line connection is made, and in particular, the situation often changes greatly as the distance increases.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a communication system such as a facsimile machine for facsimile transmitting image data to a destination communication terminal device via a communication line using a modem in an error correction mode (ECM). It is an object of the present invention to provide a communication terminal device capable of reducing the number of times of fallback and reducing communication charges.

[0006]

SUMMARY OF THE INVENTION A communication terminal device according to the present invention facsimile-transmits image data to a destination communication terminal device via a communication line in an error correction mode (ECM) using a modem. The communication control means for controlling to disconnect the communication line and set to wait for redialing when the partial page request signal is received a predetermined number of times, and when the data has already fallen back to the predetermined transmission speed. It is characterized by.

In the above-mentioned communication terminal device, preferably, the communication control means, when waiting for the redial, waits for the redial, and lowers the transmission speed before fallback, which is the start transmission speed of the previous dialing. It is characterized in that control is performed such that a call is made to a destination communication terminal device at a transmission speed of a communication mode having a transmission speed to start facsimile transmission.

Further, in the above-mentioned communication terminal device, preferably, when performing a facsimile transmission by a predetermined final redial, the communication control means falls back to a re-low transmission speed of the modem. And

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

<Embodiment> FIG. 1 shows an embodiment according to the present invention, in which facsimile transmission of image data to a destination facsimile apparatus via a public telephone network using a fax modem 10 in an error correction mode (ECM). FIG. 2 is a block diagram showing a configuration of a facsimile apparatus 20 having an ECM communication function and a redial function during training.

Facsimile machine 20 according to this embodiment
Main control unit 1 transmits a partial page request signal (PPR signal) when facsimile transmission of image data to a destination facsimile apparatus via a public telephone network in an error correction mode (ECM) using a fax modem 10. When a predetermined number of times have been received (YES in step S27 in FIG. 3), and when the data has fallen back to the predetermined transmission rate (YES in step S29), the communication line is disconnected (step S31), and a wait for redialing is set. (Step S
32).

Further, when redialing after waiting for the redialing, the main control unit 1 transmits the transmission rate of the communication mode having a transmission rate lower than the transmission rate before fallback which is the starting transmission rate at the time of the previous dialing. Is controlled to start a facsimile transmission by calling a destination communication terminal device (steps S41-43 in FIG. 4). Further, when performing facsimile transmission by predetermined final redial, the main control unit 1 causes the modem to fall back to the re-low transmission speed (FIG. 5).
Steps S81-S90).

Referring to FIG. 1, a facsimile machine 20 comprises:
It has a facsimile communication function of the conventional G3 system and the like, and has an ECM communication function of facsimile transmitting image data to a destination facsimile apparatus via a public telephone network in an error correction mode (ECM) using a fax modem 10. It has a redial function during training. The main control unit 1 is specifically composed of a CPU,
It is connected to the following hardware units via the bus 13 to control them and execute various software functions to be described later. The image reading section 2 reads an original with a scanner using a CCD or the like, and outputs dot image data converted to binary black and white. The image recording unit 3 is a printer device of an electrophotographic system or the like, and prints out and records, as a hard copy, image data received from another facsimile device by facsimile communication. The display unit 4 is a display device such as a liquid crystal display (LCD) or a CRT display, and displays an operation state of the facsimile machine 20, and displays image data of a document to be transmitted and received image data. .

The operation unit 5 includes character keys, dial numeric keys, and dial keys necessary for operating the facsimile machine 20.
It has speed dial keys, one-touch dial keys, and various function keys. In addition, by making the above-mentioned display unit 4 a touch panel type, this operation unit 5
A part or all of the various keys may be substituted.

The ROM 6 stores in advance various software programs necessary for the operation of the facsimile machine 20 and executed by the main control unit 1, wherein the programs are stored in at least the facsimile machines shown in FIGS. Includes transmission processing program. RAM7 is SRAM
Alternatively, it is constituted by a flash memory or the like, and is used as a working area of the main control unit 1 and stores temporary data generated when a program is executed. When a flash memory is used as the RAM 7, even if the power is cut off due to a power failure, a movement of the apparatus, or the like, the contents of the data are not lost. The image memory 8 is composed of a DRAM or the like, and stores image data to be transmitted or received image data. Note that the RAM 7 and the image memory 8 may be constituted by a hard disk memory.

The fax modem 10 is connected to a public telephone line L
And demodulates the data of the outgoing telephone number information received as the FSK signal and outputs it to the main control unit 1. NCU (Network control circuit: Networ
k Control Unit) 11 is a hardware circuit that performs closing and opening operations such as a DC loop of the analog public telephone line L and has an automatic dial function. The fax modem 10 is connected to the public telephone line L as necessary. Connecting.
Here, the NCU 11 detects an ID receiving terminal activation signal and a normal telephone call signal in the outgoing telephone number notification service, and transmits a primary response signal and a secondary response signal in the outgoing telephone number notification service as necessary. can do. The NCU 11 is connected to a predetermined terminal adapter and DSU (Digital Service Unit: Digital Service Unit).
Unit) may be connected to a digital line of the baseband transmission system (for example, an ISDN line).

The facsimile apparatus 20 of the present embodiment having the above-described configuration is capable of transmitting image data in the error correction mode (ECM) using the facsimile modem 10 in the error correction mode (ECM) in addition to the normal facsimile communication function such as the G3 system. E for facsimile transmission to a destination facsimile machine via a network
It has a CM communication function and a redial function during training. In the facsimile communication function, dot image data read by the image reading unit 2 is MH, MR, MM defined in the facsimile communication standard.
After being encoded by software according to an encoding method such as R, and then transmitted to the other party's facsimile machine,
Conversely, the encoded data received from the other party's facsimile machine is also decoded into image data by software and output from the image recording unit 3 as a hard copy. The image memory 8 stores the image data as needed, and outputs the stored image data as needed.

Further, V.200, which is capable of high-speed data communication such as facsimile communication. 34 mode and V.34 mode. The communication procedure in the eight modes will be described. When data communication is performed with a communication terminal device such as a facsimile device, a half-duplex system such as ITU-T Recommendation V. A T.17 mode facsimile communication procedure that uses a modem that conforms to the 17-mode communication procedure, etc. This is performed according to the procedure specified in No. 30. In addition, Recommendation V. An ultra-high-speed communication procedure having a maximum transmission rate of 33.6 kbps in accordance with ITU-T Rec.
This is called a 34-mode communication procedure. ) Has also been commercialized,
This V. In the 34-mode communication procedure, at the start of communication and during communication, the receiving side specifies the transmission rate according to the line status at that time, specifically, the S / N (signal-to-noise power ratio) and the bandwidth. The transmission side changes the transmission rate so that transmission is performed at the transmission rate specified by the reception side. In addition, V. In the case of performing data communication in the communication procedure of the 34th mode, the same recommendation V.34 is used. The pre-procedure is performed in eight communication procedures to determine the actual transmission speed.

The fax modem 10 used in the present embodiment
Is V. 34 mode, V.34. It is a high-speed modem capable of a 17-mode communication procedure, capable of changing the transmission speed during communication, and also, based on a signal received from a communication partner, the state of the communication line at that time, specifically, S / N, The bandwidth data can be externally monitored as status. In other words, the line probing process is performed between the transmitting side device and the device.
And the bandwidth are output from the fax modem 10 as a status, and the main control unit 1 reads it out and performs processing based on it.

FIGS. 2 to 5 are flowcharts showing the facsimile transmission processing executed by the main control unit 1 of the facsimile apparatus 20 of FIG.

In step S1 of FIG. 2, a call is made to the destination, and in step S2, a T0 timer is started. Next, after transmitting the CNG signal in step S3, the ANSam signal or DIS signal is transmitted in step S4.
It is determined whether a signal has been detected. If no signal has been detected, the process returns to step S3. However, if an ANSam signal has been detected, the process proceeds to step S11. If a DIS signal has been detected, the process returns to step S5. In step S5, D
V. IS signal 8 It is determined whether the ability is valid or not, and YES
In the case of, the process proceeds to step S8, whereas in the case of NO, the process proceeds to step S6. In step S6, the ITU-T Recommendation T. After executing the normal facsimile transmission process in the G3 mode based on the G.30, the line is opened in step S7, and the facsimile transmission process ends. On the other hand, in step S8, a CI signal is transmitted, and in step S9, A
It is determined whether the NSam signal or the DIS signal has been detected. If not detected, the process returns to step S8.
When a signal is detected, the process proceeds to step S11, while DI
When the S signal is detected, the process returns to step S5.

In step S11, a CM signal is transmitted. In step S12, it is determined whether a JM signal is detected. If YES, the process proceeds to step S13, while if NO, the process returns to step S11. Next, in step S13, a CJ signal is transmitted, and in step S14
In step S15, the communication mode is determined based on the FIF of the CM signal. It is determined whether the mode is the 34 mode. If NO, the process proceeds to step S6, while if YES, the process proceeds to step S1.
Proceed to 6. In step S16, the transmission rate is determined based on the determined communication mode and set to the INFOoc signal, a predetermined line probing process is executed in step S17, and a predetermined equalizer training process is executed in step S18. Step S19 in FIG.
Proceed to.

In step S19 of FIG. The transmission rate is set to 33.6 kbps in the 34 mode, the parameter Nppr for counting the number of times of receiving the PPR signal is reset to 0 in step S20, and then one block of image data is transmitted in step S21. Next, in step S22, it is determined whether a PPR signal has been received. If YES, the process proceeds to step S26 while NO
If so, the process proceeds to step S23. In step S23,
It is determined whether transmission of one page of image data has been completed. If NO, the process returns to step S21, while if YES, the process proceeds to step S24. Next, step S24
It is determined whether or not the transmission of the image data of all pages has been completed. If NO, the process returns to step S21, while if YES, the process proceeds to step S25 to release the line and end the facsimile transmission process.

In step S26 of FIG. 3, the PPR
The number of signal receptions Nppr is incremented by one, and it is determined whether or not Nppr ≧ 4 in step S27. If NO, the image data of the previous block to be transmitted is determined in step S28 as step S28.
Return to 21. On the other hand, if YES in step S27, the transmission rate is 16.8 kbp in step S29.
It is determined whether or not the time has reached s. If the answer is NO, the process falls back at step S30, that is, after reducing the transmission speed of the fax modem 10 by one step, returns to step S21. On the other hand, in step S29, Y
If it is ES, a DCN signal is transmitted in step S31, the line is opened and the line is disconnected, and step S32
After waiting for redial for 3 minutes in step, the process proceeds to step S41 in FIG.

In step S41 of FIG. 4, a call is made to the destination, and in step S42, transmission of a CNG signal,
NSF, CSI and DIS signal detection, DCS, TSI
And facsimile preprocessing such as transmission of an NSS signal and the like. After setting the transmission rate to 14.4 kbps in the 17 mode, the number of times of receiving the PPR signal Nppr is reset to 0 in step S44.
Next, in step S51, one block of image data is transmitted. In step S52, it is determined whether a PPR signal has been received. If YES, step S56 is performed.
On the other hand, if NO, the process proceeds to step S53. In step S53, it is determined whether transmission of one page of image data has been completed. If NO, the process returns to step S51, while if YES, the process proceeds to step S54. Next, in step S54, it is determined whether transmission of image data of all pages has been completed. If NO, the process returns to step S51, while if YES, step S55.
To open the line and end the facsimile transmission process.

In step S56 of FIG.
The number of signal receptions Nppr is incremented by one, and it is determined whether or not Nppr ≧ 4 in step S57. If NO, the image data of the previous transmission block is set as a transmission target in step S58 and step S58 is performed.
Return to 51. On the other hand, if YES in step S57, the transmission rate is 12.0 kbp in step S59.
It is determined whether or not the time has reached s. If the answer is NO, the process falls back at step S60, that is, after reducing the transmission speed of the fax modem 10 by one step, returns to step S51. On the other hand, in step S59, Y
If it is ES, the DCN signal is transmitted in step S61, the line is opened and the line is disconnected, and the process proceeds to step S62.
After waiting for redial for 3 minutes in step, the process proceeds to step S71 in FIG.

In step S71 of FIG. 5, a call is made to the destination, and in step S72, transmission of a CNG signal,
NSF, CSI and DIS signal detection, DCS, TSI
And facsimile pre-processing such as transmission of an NSS signal and the like. After setting the transmission speed to 9600 bps in the 29 mode, the number of PPR signal receptions Nppr is reset to 0 in step S74. Next, in step S81, one block of image data is transmitted. In step S82, it is determined whether a PPR signal has been received. If YES, the process proceeds to step S86, while if NO, the process proceeds to step S83. In step S83, it is determined whether transmission of one page of image data has been completed. If NO, the process returns to step S81, while if YES, the process proceeds to step S84. Then
In step S84, it is determined whether transmission of image data of all pages has been completed. If NO, the process returns to step S81. On the other hand, if YES, the process proceeds to step S85 to open the line and end the facsimile transmission process. .

In step S86 in FIG. 5, the PPR
The number of signal receptions Nppr is incremented by one, and it is determined whether or not Nppr ≧ 4 in step S87. If NO, the image data of the previous transmission block is set as a transmission target in step S88.
Return to 81. On the other hand, when YES is determined in the step S87, the transmission speed is set to V.0 in a step S89. It is determined whether or not the speed has become 2400 bps in the 27 mode, and if NO, the fallback is performed in step S90,
That is, after reducing the transmission speed of the fax modem 10 by one stage, the process returns to step S81. On the other hand, when YES is determined in the step S89, a DCN signal is transmitted in a step S91, the line is opened and the line is disconnected in a step S85, and then the facsimile transmission process is ended.

The above-described facsimile transmission processing shown in FIGS. 2 to 5 shows an example of a pattern of a fallback and redial call, and the processing is performed as follows. That is, V. 33.6 kb in 34 modes
Start facsimile transmission at the starting transmission rate of
1.2 kbps, 28.8 kbps, 26.4 kbp
s, when falling back in the order of 16.8 kbps,
Disconnect the line and wait for redial. Then, V. 17
Facsimile transmission is started at a start transmission rate of 14.4 kbps in the mode, and when fallback is performed to 12 kbps, the line is disconnected and standby for redialing is performed. Further, V.I.
The facsimile transmission starts at a starting transmission rate of 9600 bps in the 29 mode, falls back to 7200 bps, and 4800bps in 27ter mode,
When the data falls back in the order of 2400 bps, it is processed as a communication error.

As described above, according to the present embodiment, the main control unit 1 of the facsimile machine 20 transmits image data in the error correction mode (ECM) via the public telephone network using the fax modem 10. When the facsimile apparatus transmits a partial page request signal (PPR signal) a predetermined number of times (YES in step S27 in FIG. 3), when the data has fallen back to a predetermined transmission speed (step S29). And YE
S), the communication line is disconnected (step S31), and control is performed so as to wait for redialing (step S32).
Therefore, by trying to improve the state of the line by redialing without falling back unnecessarily, the number of times of fallback can be reduced, the communication time can be shortened, and the communication fee can be reduced.

When waiting for the redial, the main control unit 1 sets the transmission rate of the communication mode having a transmission rate lower than the transmission rate before fallback, which is the transmission rate at the time of the previous dialing, when redialing. Control to start a facsimile transmission by calling a communication terminal device of the other party (steps S41-43 in FIG. 4). Therefore, reliable facsimile communication can be expected without attempting transmission at the same speed unnecessarily, the number of times of fallback can be reduced, the communication time can be shortened, and the communication fee can be reduced.

Further, when performing the facsimile transmission by the predetermined last redial, the main control unit 1 causes the modem to fall back to the low transmission speed of the modem (steps S81-S90 in FIG. 5). Therefore, facsimile transmission can be performed more reliably by attempting communication at the maximum possible transmission speed of the fax modem 10.

Further, examples other than the fallback and redial calling patterns shown in FIGS. 2 to 5 will be described below. Here, only the last redial transmission enables fallback up to the minimum speed of 2400 bps, and the first start mode is a super G3 mode in which the number of redials is two.

<Pattern 1> At the time of the first facsimile transmission, first, the 34 mode transmission speed 33.6 kb
ps, CTC signal (correction continuation signal) and CTR
A fall-back is made with a signal (correction continuation response signal), and when a PPR signal is received four times even at a transmission rate of 14400 bps, it waits for redialing. When performing the second facsimile transmission by redialing, first, Communication at a transmission speed of 14400 bps in 17 modes, CTC signal and CT
Fallback is performed with an R signal, and when a PPR signal is received four times even at a transmission speed of 7200 bps, a redial is awaited. When a third facsimile transmission is performed by redialing, the 9600 bps transmission speed in 29 modes
, And fall back with the CTC signal and the CTR signal. If a PPR signal is received four times even at a transmission speed of 2400 bps in the 27 ter mode, a communication error occurs.

<Pattern 2> At the time of the first facsimile transmission, first, the 34 mode transmission speed 33.6 kb
ps, CTC signal (correction continuation signal) and CTR
A fall-back is made with a signal (correction continuation response signal), and when a PPR signal is received four times even at a transmission rate of 14400 bps, it waits for redialing. When performing the second facsimile transmission by redialing, first, Communication at a transmission rate of 33.6 kbps in 34 modes
Fallback is performed with an R signal, and when a PPR signal is received four times even at a transmission speed of 7200 bps, a redial is awaited. When a third facsimile transmission is performed by redialing, the Transmission speed of 34 mode: 33.6 kbp
s, fall back with CTC and CTR signals, 27ter mode transmission speed 2400bps
However, if a PPR signal is received four times, a communication error is determined. In this pattern 2, the transmission speed starting at each facsimile transmission is set to be the same.

<Pattern 3> At the time of the first facsimile transmission, first, the 34 mode transmission speed 33.6 kb
ps, CTC signal (correction continuation signal) and CTR
A fall-back is made with a signal (correction continuation response signal), and when a PPR signal is received four times even at a transmission rate of 14400 bps, it waits for redialing. When performing the second facsimile transmission by redialing, first, It communicates at a transmission rate of 28.8 kbps in 34 modes,
Fallback is performed with an R signal, and when a PPR signal is received four times even at a transmission speed of 7200 bps, a redial is awaited. When a third facsimile transmission is performed by redialing, the Transmission speed of 16.8 kbp in 34 modes
s, fall back with CTC and CTR signals, 27ter mode transmission speed 2400bps
However, if a PPR signal is received four times, a communication error is determined. In this pattern 3, the transmission speed starting at each facsimile transmission is set to V. It gradually decreases in 34 modes.

In the above pattern example, the V.V. Facsimile transmission is started in the F.34 mode. 17 mode or V.17 mode. Facsimile transmission may be started in 29 mode or the like.

<Modification> In the above embodiment, an example of the facsimile machine 20 has been described. However, the present invention is not limited to this, and is connected to a public network such as a public telephone network or a public digital network. For example, the present invention can be applied to a communication terminal device including a telephone, a data communication device, and the like.

In the above embodiment, step S27 in FIG. 3, step S57 in FIG. 4, step S8 in FIG.
Although the threshold of the number of times of receiving the PPR signal is set to 4 in 7, the present invention is not limited to this, and may be a predetermined number of 1 or more.

In the above embodiment, the fax modem 10 is a high-speed modem. However, the present invention is not limited to this, and may be a modem having a transmission speed of 14.4 kbps or 9.6 kbps.

[0041]

As described above in detail, according to the communication terminal apparatus of the present invention, the error correction mode (EC
In M), in a communication terminal device that facsimile-transmits image data to a destination communication terminal device via a communication line, when a partial page request signal is received a predetermined number of times, and when a fallback to a predetermined transmission speed has already occurred, Communication control means for disconnecting the communication line and controlling to wait for redialing. Therefore, by trying to improve the state of the line by redialing without falling back unnecessarily, the number of times of fallback can be reduced, the communication time can be shortened, and the communication fee can be reduced.

In the above-mentioned communication terminal device, preferably, the communication control means, when waiting for the redial, waits for the redial, and lowers the transmission speed before fallback which is the start transmission speed of the previous dial. Control is performed such that a call is made to the destination communication terminal device at the transmission speed of the communication mode having the transmission speed and facsimile transmission is started.
Therefore, reliable facsimile communication can be expected without attempting transmission at the same speed unnecessarily, the number of times of fallback can be reduced, the communication time can be shortened, and the communication fee can be reduced.

Further, in the communication terminal apparatus, preferably, when performing facsimile transmission by predetermined final redialing, the communication control means causes the modem to fall back to the low transmission rate of the modem. Therefore, facsimile transmission can be performed more reliably by attempting communication at the maximum possible transmission speed of the modem.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a facsimile apparatus 20 having a redial function during training, which is an embodiment according to the present invention.

FIG. 2 is a flowchart showing a first part of a facsimile transmission process executed by the main control unit 1 of the facsimile apparatus 20 of FIG.

FIG. 3 is a flowchart illustrating a second part of the facsimile transmission process executed by the main control unit 1 of the facsimile machine 20 of FIG.

FIG. 4 is a flowchart showing a third part of the facsimile transmission process executed by the main control unit 1 of the facsimile machine 20 of FIG.

FIG. 5 is a flowchart showing a fourth part of the facsimile transmission process executed by the main controller 1 of the facsimile machine 20 of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main control part, 2 ... Image reading part, 3 ... Image recording part, 4 ... Display part, 5 ... Operation part, 6 ... ROM, 7 ... RAM, 8 ... Image memory, 10 ... Fax modem, 11 ... NCU, 13: Bus, 20: Facsimile machine, L: Public telephone line.

Claims (3)

[Claims] 1. An error correction mode (EC) using a modem
In M), in a communication terminal device that facsimile-transmits image data to a destination communication terminal device via a communication line, when a partial page request signal is received a predetermined number of times, and when a fallback to a predetermined transmission speed has already occurred, A communication control unit for disconnecting the communication line and controlling the communication terminal to wait for redialing. 2. The communication control means according to claim 1, wherein, when waiting for said redialing, when redialing, the transmission rate of the communication mode having a transmission rate lower than the transmission rate before fallback, which is the starting transmission rate at the time of previous dialing. 2. The communication terminal device according to claim 1, wherein the communication terminal device controls a call to a destination communication terminal device to start facsimile transmission. 3. The communication control means according to claim 1, wherein when performing facsimile transmission by a predetermined last redial, the communication control means falls back to a low transmission rate of the modem. Communication terminal device.