JPH10271305A - Communication terminal equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of malfunctions at the time of receiving a continue-to-collect(CTC) signal during the operation in a V.34 mode. SOLUTION: The execution of a communication procedure based on T.30 ANNEXF is started (step 306), and processing is shifted to a image information receiving phase through facsimile negotiation (step 308). At the time of receiving a CTC command (YES in step 316) in the image receiving phase, a CTR response is immediately transmitted to an opposite equipment (step 318), without analyzing the CTC command to continue the image information receiving phase. Thereby contents specified by the CTC command are not executed, so that the generation of malfunctions due to invalid parameters is surely prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to the ITU-T Recommendation T. The present invention relates to a communication terminal device conforming to A.30 ANNEXF. The present invention relates to a communication terminal device that defines a countermeasure when a CTC signal is received during operation in the 34 mode.

[0002]

2. Description of the Related Art Conventionally, G3 facsimile has defined an error correction method (ECM) for correcting an error in transfer data based on a half-duplex retransmission ARQ method. Here, a schematic process of the error correction in the ECM will be described step by step according to the following.

The transmitting side divides image information data (such as facsimile coded information or a binary file) into 256 frames and transmits a partial page.

When the transmission of the partial page is completed, the transmitting side sets a PPS-EO for indicating the end of the partial page.
Transmits a P (Partial Page Signal-End of procedure) signal.

[0005] When there is a frame that could not be correctly received among the frames of the received partial page, the receiving side sends a PPR (Part) for requesting retransmission of the frame.
ial Page Request) signal to the sender. Note that P
In the PR signal, the frame to be retransmitted is indicated by setting the corresponding bit of 256 bits in the FIF (facsimile information) provided in the signal to 1.

[0006] The transmitting side receiving the PPR signal retransmits only the requested frame. When retransmission is completed, the transmitting side sends out a PPS-EOP signal.

[0007] If all frames have been received correctly, the receiving side sends an MCF (Message Confirmation) signal to the transmitting side indicating that the message has been completely received. On the other hand, if there are still frames that have not been correctly received,
Is repeatedly executed.

In the conventional G3 facsimile, if all frames cannot be transferred correctly even after retransmission three times, either retransmission is interrupted or continued, and retransmission is continued. In such a case, the following processing is executed.

That is, in response to the fourth PPR signal, the transmitting side sends a CTC (Continue To Correct) signal indicating that message correction is to be continued.
The CTC signal can indicate a command to fall back the communication speed of the modem.

When the receiving side that has received the CTC signal determines that the contents of the CTC signal can be accepted, the receiving side receives a CTR (Response To Continue) as a response to the correction continuation command.
ToCorrect) signal. As a result, four or more frame retransmissions are performed.

By the way, in ITU-T, V. 32
(2-wire system up to 9600 bps (bit par second)
14400 bps as a function extension of
The standard of a two-wire full-duplex modem up to 28800 bps exceeding V. 34; 34
As a standard that applies to the communication procedure of facsimile equipment,
ITU-T Recommendation T. 30 ANNEXF has been established. In addition,
ITU-T stands for International Telecommunications U
nion-Telecommunications Standardization Sector,
In other words, it means the telecommunication standardization section of the International Telecommunication Union.

However, this ITU-T Recommendation T. 30 ANN
In a facsimile apparatus conforming to EXF, V.V. In the high-speed operation in the 34 mode, the CTC signal which may designate the communication speed fallback and the CT
The use of the R signal has been prohibited. Therefore, ITU-
Recommendation T. In a facsimile apparatus conforming to 30 ANNEXF, A control method when a CTC signal, which is a prohibition command, is received during operation in the 34 mode is not specified.

[0013]

However, the above-mentioned conventional ITU-T recommendation T.30. In a facsimile apparatus conforming to V.30 ANNEXF, V.30. If a CTC signal is received during operation in the 34 mode, an unexpected malfunction may occur because a control method at the time of receiving the CTC signal is not specified.

The present invention has been made in view of the above-mentioned facts, and is described in ITU-T Recommendation T.30. A communication terminal device conforming to V.30 ANNEXF is V.30. An object of the present invention is to provide a communication terminal device capable of reliably preventing a malfunction even when a CTC signal is received while operating in the 34 mode.

[0015]

Means for Solving the Problems In order to solve the above-mentioned object, the invention of claim 1 is based on ITU-T Recommendation T.30. 30 ANNEX
Detecting means for detecting reception of a CTC signal indicating that the correction of image information is to be continued, in a communication terminal device compliant with F.F. While operating in the 34 mode, CT
Control means for transmitting, when the reception of the C signal is detected, a CTR signal indicating a response to the CTC signal to the other terminal without executing the content specified by the received CTC signal,
It is characterized by having.

According to the first aspect of the present invention, V.V. If the detection means detects the reception of the CTC signal during the operation in the 34 mode, the control means does not execute the content instructed by the received CTC signal, and sends a CTR signal indicating a response to the CTC signal to the other party. Send. As a result, communication can be continued and malfunction due to invalid CTC signal parameters can be reliably prevented.

Here, after analyzing the received CTC signal, the control means may transmit the CTR signal without executing the content thereof, or alternatively, the control means may transmit the CTR signal without executing the contents. 1. The control means according to When the detection means detects the reception of the CTC signal during the operation in the 34 mode, the CTR signal may be transmitted to the partner device without analyzing the received CTC signal. According to the second aspect of the present invention, the analysis of the CTC signal is not performed.
There is an advantage that a signal can be transmitted.

Further, according to a third aspect of the present invention, the control means of the first aspect further comprises: If the detection means detects the reception of the CTC signal while operating in the 34 mode, the received CT
The transmission of the CTR signal to the partner device is not performed without at least specifying the communication speed parameter among the contents specified by the C signal.

According to the third aspect of the present invention, since at least the communication speed parameter is not specified in the content specified by the received CTC signal, the communication is continued and the malfunction due to the invalid communication speed parameter is reliably prevented. And effective parameters other than the communication speed can be reset.

The invention according to claim 4 is based on the ITU-T Recommendation T.30. In a communication terminal device conforming to 30 ANNEXF,
Detecting means for detecting reception of a CTC signal indicating that the correction of the image information is to be continued; And interrupting means for interrupting communication with the partner device when the detection means detects the reception of a CTC signal during operation in the 34 mode.

According to the fourth aspect of the present invention, V.V. When the reception of the CTC signal is detected during the operation in the 34 mode, the communication with the partner device is interrupted, so that the malfunction caused by the reception of the invalid CTC signal can be more reliably prevented.

The interruption means may be, for example, DCN
There is a means for disconnecting a line by transmitting a signal.
Of course, the communication may be interrupted without using the DCN signal.

Further, the invention according to claim 5 further comprises output means for outputting an error message to the effect that an invalid command has been received when communication with the partner machine is interrupted by the interruption means according to claim 4. It is characterized by the following.

According to the fifth aspect of the present invention, by outputting an error message indicating that an invalid command has been received,
It is possible to clarify that a command not permitted to be used has been received.

Further, the invention of claim 6 is based on ITU-T Recommendation T.30. In a communication terminal device conforming to 30 ANNEXF,
Detecting means for detecting reception of a CTC signal indicating that the correction of the image information is to be continued; Control means for immediately executing the next operation processing without performing analysis of the received CTC signal and processing related to the received CTC signal when the detection means detects the reception of the CTC signal while operating in the 34 mode; It is characterized by having.

According to the sixth aspect of the present invention, the V.V. When the reception of the CTC signal is detected during the operation in the 34 mode, the received CTC signal is detected.
Without performing the analysis of the TC signal and the processing related to the signal,
Since the next operation process is immediately executed, a malfunction due to the CTC signal can be prevented with the simplest configuration.

[0027]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 shows a facsimile apparatus 1 as an example of a communication terminal apparatus according to a first embodiment of the present invention.
FIG. This facsimile machine 10
CPU 1 for controlling the entire facsimile machine 10
2. RAM 14 as a work area used when executing the control program, operation display device 1 provided with display and operation switches for operating facsimile device 10
6. A reading device 18 for reading a transmission original, a printing device 20 for printing and outputting received image information, etc., encoding / decoding / enlargement /
An image processing device 22 that performs image processing such as reduction, and an image storage device 2 that stores image information to be transmitted or received image information
4. A system control program storage unit 28 composed of a ROM storing a program for controlling the entire facsimile apparatus 10, and a program for controlling communication (for example, G4) suitable for a digital network (for example, an ISDN network). Communication control program storage unit 30 composed of a read-only ROM, analog communication control program storage unit 32 composed of a ROM storing a program for controlling communication suitable for an analog network (for example, G3), and facsimile device 10. A digital network controller 38 for connecting the FAX to a digital network, an analog network controller 40 for connecting the facsimile machine 10 to an analog network, and for connecting a plurality of external line interfaces and a plurality of internal communication circuits by switching. And a line switching control device 36 of They are connected to each other by a system bus 26.

The digital communication control program storage unit 30 is mutually connected to the direct line switching control unit 36, and the analog communication control program storage unit 32 is a modem (modem / demodulation device) having a low-speed mode and a high-speed mode. 3
4 and is mutually connected to the line switching control device 36. Further, the line switching control device 36 is mutually connected to each of the digital network control device 38 and the analog network control device 40.

Facsimile machine 10 of the first embodiment
Can be connected to both digital and analog networks,
When the facsimile machine 10 is connected only to an analog network, the digital communication control program storage unit 30 and the digital network control unit 38 can be omitted. , The modem 34 and the analog network controller 40 can be omitted.

The facsimile apparatus according to the first embodiment is based on ITU-T Recommendation T.30. Communication based on a protocol procedure conforming to 30 ANNEXF is enabled. Therefore,
ITU-T Recommendation T. An outline of a basic communication procedure of 30 ANNEXF will be described below with reference to FIG.

As shown in FIG. 2, the signal sent from the calling station to the answering station is on the left side of the center line, and the signal sent from the answering station to the calling station is on the right side of the center line. They are shown in order from the top along the sequence.

FIG. 2 covers a procedure at the start of communication, a procedure at the time of transmitting image information, and a procedure at the end of communication. Among these, the procedure at the start of communication includes network interaction (phase 1) for recognizing the functions and the like of the partner terminal, and a line for grasping the state of the communication line set between the calling station and the answering station. Probing (Phase 2), Primary channel equalizer training (Phase 3) for training the equalizer built in the modem, Modem parameter exchange (Phase 2) for exchanging the performance information of the modem and setting the data signal speed T.4), for exchanging control channel data before transmitting image information. 30 facsimile handshake (phase 5),
Prior to the transmission of the image information, the primary channel is resynchronized. The primary channel is resynchronized (phase 6).

In the network interaction, V.30 is used. 8 is performed, and after the next line probing, V.8 is performed. The operation based on the 34 half-duplex operation mode is performed.

By the way, as described above, the ITU-T
Recommendation T. In a facsimile apparatus conforming to V.30 ANNEXF, V.30. During operation in the 34 mode, use of a CTC signal (hereinafter, referred to as “CTC command”) and a CTR signal (hereinafter, referred to as “CTR response”) is prohibited. Therefore, in the facsimile apparatus of the present embodiment, as described later, a prevention process for reliably preventing an unexpected malfunction that occurs when a CTC command is received is defined. Here, first, the CTC command and the CT
The data structure of the R response will be described with reference to FIG.

As shown in FIG. 8, the CTC command includes a flag F indicating the beginning of the command, an address field A indicating the address of the receiving side, a control field C used for a command and response for controlling the data link, a command , A facsimile information field FIF in which additional information is stored, a frame checking sequence FCS for checking a transmission error on the receiving side, and a flag F indicating the end of the command.

The facsimile control field F
The value of CF is defined as “X1001000”,
The CPU 12 of the facsimile apparatus 10 detects that the received command is a CTC command by the fact that the value of the facsimile control field of the received command is the above value. That is, the facsimile apparatus 10 of the present embodiment
Has a function of detecting a CTC command.

The facsimile information field FIF
Is used to specify the communication speed of the receiving modem.
6 bits of information can be stored, and the CPU 12 of the facsimile device 10 When communication is performed in 30 steps, control is performed so that the communication speed of the modem becomes the communication speed specified by the facsimile information field FIF. That is, the facsimile apparatus 10 of the present embodiment
Has a function of analyzing the contents of the CTC command.

As shown in FIG. 8, the CTR response includes a flag F indicating the start of the response, an address field A indicating the address of the response receiving side, a control field used for a command for controlling the data link and a response. C, a facsimile control field FCF indicating the identification code of the response, a frame checking sequence FC for checking a transmission error on the receiving side
S and a flag F indicating the end of the command. Note that the facsimile machine 10 of the present embodiment has a function of creating and transmitting a CTR response having the data structure of FIG.

Of these, the facsimile control field F
The value of CF is defined as “X01000011”,
The facsimile apparatus that has received the response detects that the received response is a CTR response based on the value of the facsimile control field being the above value.

Next, using the flowchart of FIG.
The operation of the communication terminal device according to the embodiment will be described. Note that the flowchart of FIG. 3 shows the flow of processing when the communication terminal device of the present embodiment has become a response station (reception-side terminal).

As shown in the flowchart of FIG. 3, first, an incoming call from a calling station (transmitting terminal) is waited for.
If there is an incoming call (step 300, affirmative determination), 34 negotiations. 8 steps (Step 30)
2). This V. In the eight procedures, as described above, network interaction (phase 1 in FIG. 2) for recognizing the function and the like of the partner terminal is executed.

Next, according to the result of the network interaction in step 302, It is determined whether 34 negotiations have been established (step 304). V.
If the T.34 negotiation is not established (No in step 304), the normal T.34 negotiation is not performed. Step 30 is executed (Step 324).

V. If the T.34 negotiation is established (Yes at step 304), the T.34 negotiation is performed. The operation of 30 ANNEXF is started (step 306). That is, after this,
T. V.30 in accordance with ANNEXF. The protocol procedure in the 34 mode is executed.

In this protocol procedure, as shown in FIG. 2, after line probing, primary channel equalizer training, and modem parameter exchange processing are sequentially executed, 30 handshaking is performed as a facsimile negotiation (step 30)
8). When the facsimile negotiation is completed, the responding station sets the CF indicating that the preparation for reception is completed.
After transmitting the R signal, the calling station performs resynchronization of the primary channel (FIG. 2).

Then, the process proceeds to the image information receiving phase (FIG. 2) (step 310). In the image information receiving phase, the calling station divides the image information into a predetermined number of frames, and sequentially transmits the divided frames for each partial page.

Next, it is determined whether or not the image information receiving phase has been completed (step 312). If the image information receiving phase has not been completed (No in Step 312), that is, if image information reception has continued, it is determined whether any command has been received (Step 31).
4). If no command has been received (step 314)
(No), the process returns to step 312, and the same process is repeated until the image information receiving phase ends.

On the other hand, when the command is received (Yes at Step 312), it is determined whether the received command is a CTC command (Step 316). If it is determined that the received command is a CTC command (Yes at Step 316), a CTR response is transmitted (Step 318), and the process returns to Step 312 to repeat the same processing.

If the received command is not a CTC command (No at Step 316), an operation process corresponding to the received command is executed (Step 320), and the process returns to Step 312 to repeat the same process.

When the image information receiving phase is completed (Yes at step 312), the T.P. The end operation of 30 ANNEXF is executed to complete the communication procedure.

As described above, T.P. Even if a CTC command that should have been prohibited is received during the execution of a communication procedure conforming to 30 ANNEXF, in the present embodiment,
The CTR response is immediately transmitted without analyzing the content of the received CTC command, and the image information receiving phase is continued. As a result, communication can be continued, and malfunction due to invalid CTC command parameters can be reliably prevented.

As a procedure when the CTC command is received in step 316 of FIG. 3, even if the received command is analyzed, the CTR response is transmitted without resetting the parameters based on the analysis result. Can achieve the same effect.

For comparison, the normal T.D. of step 324 in FIG. The flow of the image information receiving phase in the 30 procedures will be described with reference to the flowchart of FIG.

As shown in the flowchart of FIG. 4, when the image information receiving phase is not completed (step 40).
If the CTC command is received (step 402, affirmative determination), the contents of the received CTC command are analyzed (step 404). By this analysis, the facsimile information field FI of the received CTC command is
A parameter designated by F, for example, a communication speed of a modem is detected.

Next, the analyzed parameters are reset (step 406). For example, the communication speed or the like of the modem is reset to the value specified by the CTC command. Then, a CTR response is transmitted (step 408), and the process returns to step 400 to repeat the same processing.

When the image information receiving phase is completed (Yes at Step 400), the normal T.P. 30 is performed (step 410). 30 communication procedures are completed.

As described above, the ordinary T.P. In the 30 steps,
T. In 30 ANNEXF, parameters such as the communication speed specified by the prohibited CTC command are reset, and a CTR response indicating the response to the reset command is transmitted, and the image information receiving phase is continued. (Second Embodiment) Next, a communication terminal device according to a second embodiment will be described using a facsimile machine as an example. Note that the configuration and the basic communication procedure of the second embodiment are the same as those of the first embodiment (FIGS. 1 and 2).
The same reference numerals are given and the detailed description is omitted.

The operation of the second embodiment will be described with reference to the flowchart of FIG. 3 and 4 are denoted by the same step numbers and will not be described, and only different portions will be described.

As shown in the flowchart of FIG. 5, when it is determined that the received command is a CTC command (Yes at Step 316), the CTC command is analyzed (Step 330). By this analysis, the parameter specified by the facsimile information field FIF of the CTC command is detected.

Next, among the parameters detected by the analysis in step 330, parameters other than the communication speed are reset (step 332). Then, a CTR response is transmitted (step 334), the process returns to step 312, and the same processing is repeated until the image information receiving phase ends.

As described above, in the second embodiment, the T.D. 30
Even if a CTC command that is supposed to be prohibited is received during the execution of the communication procedure conforming to ANNEXF, only the parameters other than the communication speed specified by the received CTC command are reset, and the CTR response is transmitted. To continue the image information receiving phase. Accordingly, communication can be continued, malfunctions due to invalid communication speed parameters can be reliably prevented, and valid parameters other than the communication speed can be reset. Third Embodiment Next, a communication terminal device according to a third embodiment will be described using a facsimile machine as an example. Note that the configuration and the basic communication procedure of the third embodiment are the same as those of the first embodiment (FIGS. 1 and 2).
The same reference numerals are given and the detailed description is omitted.

The operation of the third embodiment will be described with reference to the flowchart of FIG. 3 and 4 are denoted by the same step numbers and will not be described, and only different portions will be described.

As shown in the flowchart of FIG. 6, when it is determined that the received command is a CTC command (Yes at step 316), a DCN (Disconnect) command, which is a line disconnect command signal, is transmitted (step 336). ). As a result, the line is disconnected and the communication ends. Then, the facsimile machine 10 on the responding station side (reception side of the CTC command) outputs an error message indicating that the invalid command has been received (step 338). In this step 338, the invalid command reception error message is displayed on the operation display device 16 in FIG. 1 or printed by the printing device 20, for example.

As described above, in the third embodiment, the T.D. 30
If a CTC command that is supposed to be prohibited is received during the execution of the communication procedure conforming to ANNEXF,
The line is disconnected by transmitting the CN command to terminate the communication. As a result, malfunctions caused by receiving invalid CTC commands can be more reliably prevented.

Further, by outputting an error message indicating that an invalid command has been received, it is possible to clarify that a command not permitted to be used has been received. (Fourth Embodiment) Next, a communication terminal apparatus according to a fourth embodiment will be described using a facsimile apparatus as an example. Note that the configuration and the basic communication procedure of the fourth embodiment are the same as those of the first embodiment (FIGS. 1 and 2).
The same reference numerals are given and the detailed description is omitted.

The operation of the fourth embodiment will be described with reference to the flowchart of FIG. 3 and 4 are denoted by the same step numbers and will not be described, and only different portions will be described.

As shown in the flowchart of FIG. 7, when it is determined that the received command is a CTC command (Yes at step 316), the process immediately returns to step 312 and repeats the same processing until the image information receiving phase ends. .

As described above, in the fourth embodiment, the T.D. 30
When a CTC command that should have been prohibited is received during the execution of a communication procedure conforming to ANNEXF, a CTR response is transmitted as in the above embodiments,
The normal operation is executed without analyzing the CTC command or interrupting the communication. That is, the CTC command is read and discarded, and the process waits for a command reception in step 314. Thus, with the simplest configuration, a malfunction due to the CTC command can be prevented.

The embodiments of the present invention have been described above, but the present invention is not limited only to the above-described examples. For example,
In each of the above flowcharts, the example in which the calling station side terminal transmits the CTC command to the answering station side terminal has been described. However, even when the responding station side becomes the data transmitting side and transmits the CTC command to the calling station side, The present invention can be applied.

[0069]

As described above, according to the first aspect of the present invention, the V.V. If the reception of the CTC signal is detected during the operation in the 34 mode, the content indicated by the received CTC signal is not executed, and the CT indicating the response to the CTC signal is not executed.
Since the R signal is transmitted to the partner device, it is possible to obtain the effect that communication can be continued and malfunction due to an invalid CTC signal can be reliably prevented.

According to the second aspect of the present invention, V.V. 34
When the reception of the CTC signal is detected while operating in the mode,
Since the received CTC signal is not analyzed and the CTR signal is transmitted to the partner device, the communication can be continued and the malfunction due to the invalid CTC signal can be reliably prevented. Can be

According to the third aspect of the present invention, at least the communication speed parameter is not specified among the contents specified by the received CTC signal.
An effect is obtained that communication can be continued, malfunctions due to invalid communication speed parameters can be reliably prevented, and valid parameters other than the communication speed can be reset.

Further, according to the fourth aspect of the present invention, the V.V. 3
When the reception of the CTC signal is detected during the operation in the 4 mode, the communication with the partner device is interrupted, so that the malfunction caused by the reception of the invalid CTC signal can be more reliably prevented. The effect is obtained.

According to the invention of claim 5, according to claim 4,
In the invention of the above, an error message indicating that an invalid command has been received is output, so that it is possible to clarify that communication has been interrupted by receiving a command not permitted to use. The effect is obtained.

Further, according to the invention of claim 6, the V.V. 3
When the reception of the CTC signal is detected during the operation in the 4 mode, the analysis of the received CTC signal and the processing related to the signal are not performed, and the next operation processing is immediately performed. An effect is obtained that a malfunction due to the CTC command can be reliably prevented.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram when a communication terminal device of the present invention is configured as a facsimile device.

[Fig. 2] ITU-T Recommendation T. It is a figure which shows the outline | summary of the basic communication procedure of 30 ANNEXF.

FIG. 3 is a flowchart showing a communication flow of the facsimile apparatus according to the first embodiment of the present invention.

FIG. 4 is a diagram showing a general T.C. in a facsimile apparatus according to the first embodiment of the present invention; It is a flowchart which shows the flow of 30 image information reception phases.

FIG. 5 is a flowchart illustrating a communication flow of the facsimile apparatus according to the second embodiment of the present invention.

FIG. 6 is a flowchart illustrating a communication flow of a facsimile apparatus according to a third embodiment of the present invention.

FIG. 7 is a flowchart showing a communication flow of a facsimile apparatus according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a data structure of a CTC command and a CTR response.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 facsimile device 12 CPU 16 operation display device 20 printing device 28 system control program storage unit 30 digital communication control program storage unit 32 analog communication control program storage unit 34 modem 36 line switching control device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hirotaka Kawabata 3-7-1, Fuuchi, Iwatsuki-shi, Saitama Prefecture Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Hiroaki Sakaki 3-7-1, Fuuchi, Iwatsuki-shi, Saitama Prefecture 1 Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Masahiro Mochizuki 3-7-1 Fuchu, Iwatsuki City, Saitama Prefecture Fuji Xerox Co., Ltd. Iwatsuki Office (72) Inventor Yoshihiro Maui In Iwatsuki City, Saitama Prefecture 3-7-1, Fuji Xerox Co., Ltd. Iwatsuki Office

Claims (6)

[Claims] 1. An ITU-T Recommendation T. C. A communication terminal device conforming to ANNEXF, wherein a detecting means for detecting reception of a CTC signal indicating that the correction of the image information is to be continued; Control means for transmitting a CTR signal indicating a response to the CTC signal to the other terminal without executing the content specified by the received CTC signal when the reception of the CTC signal is detected by the detection means during operation in the 34 mode; A communication terminal device comprising: 2. The control device according to claim 1, wherein 2. The communication terminal device according to claim 1, wherein when the detection means detects the reception of the CTC signal while operating in the 34 mode, the received CTC signal is not analyzed and the CTR signal is transmitted to the other terminal. . 3. The control device according to claim 1, wherein If the CTC signal is detected by the detection means during the operation in the 34 mode, at least the communication speed parameter is not specified in the content specified by the received CTC signal, and the CTR signal is transmitted to the partner device. The communication terminal device according to claim 1, wherein: 4. An ITU-T Recommendation T. 30. A communication terminal device compliant with A.30 ANNEXF, comprising: detecting means for detecting reception of a CTC signal indicating that the correction of image information is to be continued; 34. A communication terminal device, comprising: interruption means for interrupting communication with a partner device when reception of a CTC signal is detected by the detection means during operation in a 34 mode. 5. The communication device according to claim 4, further comprising: an output unit that outputs an error message indicating that an invalid command has been received when the communication with the partner device is interrupted by the interruption unit. Terminal device. 6. An ITU-T Recommendation T.6. A communication terminal device conforming to A.30 ANNEXF, wherein a detecting means for detecting reception of a CTC signal indicating that the correction of the image information is to be continued; Control means for immediately executing the next operation processing without performing analysis of the received CTC signal and processing related to the signal when the reception of the CTC signal is detected by the detection means during operation in the 34 mode; A communication terminal device comprising: