JP3345263B2 - Communication control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control device, and more particularly to a communication control device capable of performing communication corresponding to a change in a frame length in a communication system in which data is framed for communication.

[0002]

2. Description of the Related Art In a data communication system such as a facsimile, there is a method of performing communication by forming data in a frame in an HDLC mode. In this method, an error check field called CRC is provided in a frame, and the normality or abnormality of the transmitted frame data is determined here.

There is also a communication system for performing digital line communication between G3 facsimile units via an adapter. In this communication system, the analog line between the transmitting facsimile and the adapter, the digital line between the adapter,
An analog line between the adapter and the receiving facsimile, 3
Data is transmitted and received via two lines. Each adapter performs data conversion between analog data and digital data. 2. Description of the Related Art A conventional communication device of this type is, for example, one shown in FIG. In FIG. 7, reference numeral 1a denotes a facsimile machine (referred to as a receiving side), 1b denotes a transmitting side facsimile apparatus, 3a denotes a private branch exchange connected to the receiving side facsimile apparatus 1a, and 3b denotes a transmitting side facsimile apparatus 1b.
The private branch exchange 4a is connected to a TDM device provided with a FAX modem 5a for demodulating data to the receiving facsimile device 1a, and the private branch exchange 4a is used for demodulating data to the transmitting facsimile device 1b. This is a TDM device provided with a FAX modem 5b. On the receiving side,
The connection from the receiving facsimile apparatus 1a to the TDM apparatus 5a is connected by an analog line 2a. On the transmitting side, the transmitting side facsimile apparatus 1b to the TDM apparatus 5
The connection up to b is connected by the analog line 2b.
Also, the TDM device 4a on the receiving side and the TDM device 4 on the transmitting side
b is connected by a digital line 6.

In a communication apparatus having such a configuration, data transmitted by the transmitting facsimile machine 1b is modulated by the FAX modem 5b, and the modulated data is transferred to the FAX modem 5a on the receiving side. FAX modem 5
a receives the data transferred from the digital line 6,
Image data communication is performed by transmitting data to the reception-side facsimile 1a. A description will be given of a data configuration in a case where the digital line 6 is set to the BOP mode (HDLC format) to perform ECM communication in order to perform such data transmission and reception. FIG. 8 shows communication with a normal data configuration (data is sent from right to left in the figure). In this case, the data structure is such that one frame includes transmission data such as image data having a 4-byte header and a 256-byte data structure (total data length 260
Byte), and a CRC code for error checking is added after the transmission data. Then, the FAX modem 5b on the transmitting side transmits the data having the above-described frame configuration to the facsimile apparatus 1b on the transmitting side.
, And recognizes that the data of the normal frame has been received, and transmits the data to the facsimile machine 1a on the receiving side via the digital line 6. FA on the receiving side
The X modem 5a receives the 260-byte frame-structured data and if the CRC of the data is normal,
Facsimile machine 1 on the receiving side via analog line 2a
The data is transmitted to a.

On the other hand, in the ECM communication, as shown in FIG. 9, there is a case where data composed of short frames each having less than 260 bytes (for example, 100 bytes or 200 bytes) is transmitted. is there. This is found in the frame corresponding to the last frame of the transmission data composed of a plurality of frames, and the FAX modem 5b on the transmission side operates the facsimile apparatus on the transmission side for data having a short frame structure as described above. 1b, and transmits data to the facsimile machine 1a on the receiving side.

[0006] In contrast to the above-described transmission operation when the transmission data is normal, if the transmission data is abnormal, abnormal processing is performed by a method as shown in FIG. FIG. 10 illustrates an abnormal process performed by the FAX modem 5a on the receiving side when an error occurs on a digital line from the FAX modem 5b on the transmitting side to the FAX modem 5a on the receiving side and an error occurs in a frame of transmission data. FIG. In this case, the receiving-side FAX modem 5a receives the 260-byte frame configuration data or the short-frame configuration data. If the CRC of the data is abnormal, the reception-side facsimile machine 1a sends the data to the receiving-side facsimile machine 1a via the analog line 2a. The data is transmitted as an abnormal frame to the user.

[0007]

However, when performing data communication, for example, on the transmitting side, the F on the transmitting side is required.
During the processing operation in which the AX modem 5b receives data from the facsimile machine 1b on the transmitting side and further transfers the data on the digital line 6, the data transmission from the facsimile machine 1b is delayed and sent out in one frame. The data is divided into two frames (20
The digital line 6 is divided into 0 bytes and 60 bytes).
May be sent up. In such a case, in the above-mentioned conventional communication device, the receiving-side FAX modem 5a mistakenly recognizes each of the two divided frames as the short frame shown in FIG. Performs a CRC check on
If the RC is normal, it transmits as a normal frame to the receiving facsimile machine 1a. Then, the facsimile machine 1a on the receiving side performs a communication disconnection process as an error over because erroneous data is received, so that subsequent communication cannot be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a data communication system in which an input / output means on a receiving side accurately determines whether data received from a public line is a normal frame. It is to provide a communication control device which can be used.

[0009]

According to the present invention, a first facsimile terminal 1b is provided in a communication control device to achieve the above object.
1st in / out for facsimile communication with analog line
Power means, second facsimile terminal 1a and analog line
For the data terminal 4a for more facsimile communication,
Data communication using HDLC frame via digital line
Second input / output means, first input / output means, and second input / output means
Control means for controlling input and output with the
The control means transmits data from the first facsimile terminal 1b.
If the data is an error frame, the data
The gist is that the data length is made longer and transmitted to the digital line .

Therefore, the communication control device on the receiving side can determine whether the frame is normal or abnormal by checking whether the number of bytes of the frame of the received data matches the specified number of bytes. In this way, by setting the normal frame to a predetermined length at all times, the normal frame and an abnormal frame such as a frame obtained by dividing a frame that was originally one for the sake of processing are transmitted to the other communication control device. It can be surely distinguished.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the first aspect of the present invention, a communication control apparatus includes a first facsimile terminal 1b and an analog terminal.
First input / output means for performing facsimile communication via a log line
And the second facsimile terminal 1a and an analog line.
Digital for data terminal 4a for facsimile communication
2nd data communication using HDLC frame via line
Input / output means, input of the first input / output means and second input / output means
Control means for controlling the output.
The control means receives data from the first facsimile terminal 1b.
In the case of a color frame, the data is larger than a predetermined byte.
Data length and sending it to a digital line.
To make sure that the frame is in error
The other party can notify
This has the effect that it can be easily determined that the event has occurred on the log line .

[0012]

[0013] The invention described in claim 2 of the present invention is the first filter.
Facsimile via facsimile terminal 1b and analog line
First input / output means for re-communication, and second facsimile terminal 1
Data terminal for facsimile communication with a and an analog line
HDLC frame via digital line to terminal 4a
A second input / output means for performing facsimile communication by
A control means for controlling input / output between the output means and the second input / output means
And the control means comprises a first facsimile terminal 1
If the number of bytes of data from b does not reach the specified number
In this case, zero data is added to the HDLC frame of the specified number of bytes.
While it is transmitting to the digital line in the arm, if the data is an error frame from the first facsimile terminal 1b which was to be sent a pre <br/> Symbol data to the digital line and the data length of more than a predetermined number of bytes Yes, it is possible to make the receiving side recognize the normality / abnormality of the frame based on the frame length, and it is possible to reliably notify the other side that the frame is an error frame, and further, the other side This has the effect that it can be easily determined that the error has occurred on the analog line.

According to a third aspect of the present invention, there is provided a communication control apparatus wherein first input / output means for performing facsimile communication with the first facsimile terminal 1a through an analog line, and facsimile communication with the second facsimile terminal 1b through an analog line. Second input / output means for performing data communication with a data terminal 4b to be connected via a digital line,
Control means for controlling input / output with the input / output means, the control means comprising: a second facsimile terminal 1b
If it is determined that the number of bytes from the data has not reached the predetermined number of bytes, even if the CRC in the frame is normal, the frame is rewritten as abnormal and sent to the first facsimile terminal 1a , so that the processing capability of the transmission Even if what is to be transmitted as a CRC error is transmitted as a normal CRC, it is possible to reliably determine that the frame is an error frame.

According to a fourth aspect of the present invention, there is provided a communication control apparatus wherein first input / output means for performing facsimile communication with the first facsimile terminal 1a via an analog line, and facsimile communication with the second facsimile terminal 1b via an analog line. Second input / output means for performing data communication with a data terminal 4b to be connected via a digital line,
Control means for controlling input / output with the input / output means, the control means comprising: a second facsimile terminal 1b
It detects whether there is a predetermined data pattern at the beginning of the data received from the data terminal 4b, and if there is a data pattern, determines whether or not the received data reaches a predetermined number of bytes. If not, even if the CRC in the frame is normal, it is rewritten as abnormal and the first
By transmitting the data to the facsimile terminal 1a , if the data to be transmitted as one frame is divided for some reason, the first half of the frame is transmitted to ensure continuity of communication and prevent unnecessary communication. Has an action.

According to a fifth aspect of the present invention, there is provided a communication control apparatus wherein first input / output means for performing facsimile communication with the first facsimile terminal 1a via an analog line, and facsimile communication with the second facsimile terminal 1b via an analog line. Second input / output means for performing data communication with a data terminal 4b to be connected via a digital line,
Control means for controlling input / output with the input / output means, the control means comprising: a second facsimile terminal 1b
Of the data received from the data terminal 4b , the presence or absence of a predetermined data pattern is detected. If there is no data pattern, the frame is determined to be an error frame regardless of the content of the CRC and discarded, so that communication continuity is maintained. When an error frame is transmitted to the receiving-side facsimile machine in order to ensure the communication, unnecessary frames are discarded, thereby preventing unnecessary communication.

[0017]

The invention described in claim 6 of the present invention is the invention
In the communication control device according to 3 or 4 , the control means includes:
Detecting whether there is a predetermined data pattern at the beginning of the data received from the data terminal of the second facsimile terminal,
If there is no data pattern, it is determined to be an error frame regardless of the content of the CRC and discarded.
Due to the processing capability of the transmitting side, even if what should be transmitted as a CRC error is transmitted as a normal CRC , the receiving side can reliably determine that the frame is an error frame, and one frame should be originally determined. If the data to be sent is divided for some reason, the first half of the frame is transmitted to ensure continuity of communication and prevent unnecessary communication. When an error frame is transmitted to a facsimile machine, unnecessary frames are discarded, and this has the effect of preventing useless communication.

According to a seventh aspect of the present invention, in the communication control apparatus according to the first to sixth aspects, the predetermined number of bytes is a number of bytes constituting one frame of HDLC mode data. This has the effect of making various decisions using one frame of HDLC mode data.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of a communication control device according to the present invention. In FIG.
Reference numeral 1 denotes a communication control device. This communication control device 11 is shown in FIG.
, The receiving-side facsimile machine 1a,
A transmitting / receiving facsimile machine 1b, a private branch exchange 3a connected to the receiving facsimile machine 1a via an analog line 2a, a private branch exchange 3b connected to the transmitting facsimile device 1b via an analog line 2b, and a receiving facsimile. A TDM device 4a as a communication control device having a FAX modem 5a for performing data modulation and demodulation processing with the device 1a; a transmission facsimile device connected to the TDM device 4a via a digital line 6; 1b, a TDM device 4b as a communication control device including a FAX modem 5b for performing data modulation and demodulation processing.
a and 4b, which perform high-speed digital communication with the other party's communication control device 11 connected via a digital line. The communication control device 11 is provided with a codec 12 for encoding / decoding audio.

Reference numeral 13 denotes a FAX modem.
The X modem 13 includes a control unit 14, a read-only memory (ROM) 15, a rewritable memory (RAM) 16
A data input / output unit 17 for performing a serial data input / output processing operation, a digital interface circuit 18,
A bus 19 connecting these functional units is provided. The analog side of the FAX modem 13 is an analog line 20.
On the other hand, the digital side of the FAX modem 13 is connected to a digital line 21. Control unit 14
Is constituted by a CPU, and a program for operating the control unit 14 is stored in the ROM 15.
The control unit 14 converts a facsimile signal input from the private branch exchange into a digital signal and outputs the digital signal from the digital interface circuit 18, and converts a digital signal input from the digital line 21 via the digital interface circuit 18 into a facsimile signal and converts the digital signal into a facsimile signal. Output to exchange. Further, when a facsimile control signal indicating the start of facsimile communication is transmitted from the transmission-side facsimile device 1b as a facsimile signal,
Recognizing this, it converts it into a specific signal corresponding to the type of facsimile control signal and outputs it to the digital line 6. on the other hand,
When a specific signal corresponding to the type of facsimile control signal is received from the digital line 6, it is recognized, converted to a facsimile control signal corresponding to the type, and output to the private branch exchange 3a.

The operation of the communication control device having such a configuration will be described below with reference to FIGS. FIG. 2 shows a transmitting facsimile 1b and a receiving facsimile 1a.
FIG. 9 is a flowchart illustrating a transmission control operation of the communication control apparatus according to the present embodiment when facsimile communication of ECM data by HDLC is performed between the communication control apparatus and the HDLC. FIG.
FIG. 5 is a flowchart illustrating a reception control operation of the communication control apparatus according to the present embodiment when performing facsimile communication of ECM data by HDLC between the transmission-side facsimile 1b and the reception-side facsimile 1a.

In the flowchart shown in FIG. 2, when the ECM data transmission control is started, in a processing step (hereinafter simply referred to as a step) ST1, it is checked whether or not data has been received from the modem. If not, this check operation is repeated. If the data has been received, the data is transferred to the data input / output unit 17 in step ST2, and it is checked in step ST3 whether or not the frame reception has been completed. In this check operation, if the frame reception has not been completed, the process returns to step ST1 to repeat the operations of steps ST1 to ST3, while if the frame reception has been completed, the process returns to step ST1.
In step 4, it is checked whether the data transferred frame is an error frame. If it is not an error frame, it is checked in step ST5 whether the number of bytes of the transfer data has reached the specified number of bytes (eg, 260 bytes), and if the number of bytes of the transfer data has reached the specified number of bytes. Transmits the transfer data to the digital line 6 as a normal frame, and completes the ECM data transmission control operation for one frame. On the other hand, if the number of bytes of the transfer data has not reached the specified number of bytes in the check operation in step ST5, the "0" data is transferred to the data input / output unit 17 to increase the number of bytes of the transfer data in step ST6. At the same time, it is checked again in step ST5 whether the number of bytes of the transfer data has reached the specified number of bytes, and this processing is repeated until the number of bytes of the transfer data reaches the specified number of bytes. Then, when the number of bytes of the transfer data reaches the prescribed number of bytes, the transfer data (this is a normal frame) is sent out onto the digital line 6, and the ECM data transmission control operation for one frame is completed.

According to the above-described processing operation, in the present embodiment, when the data-transferred frame is a normal frame, the number of bytes of the frame matches or does not match the specified number of bytes ( Also in the case of a so-called short frame), the transmission-side communication control device always transmits the data after the number of bytes of the transfer data is corrected to the specified number of bytes. That is, a frame whose initial data length is 200 bytes as shown in FIG. 4 (normal frame)
Is transmitted, the communication control device on the transmission side adds "0" data to the frame, increases the number of bytes of the transfer data to 260 bytes, and transmits the frame. Therefore, the communication control device on the receiving side can determine whether the frame is normal or abnormal by checking whether the number of bytes of the frame of the received data matches the specified number of bytes.
This allows the receiving side to recognize whether the frame is normal or abnormal on the basis of the frame length, and always sets the normal frame to a predetermined length, so that the normal frame is, for example, one frame for convenience of processing. The abnormal communication frame such as the divided frame can be reliably distinguished by the other communication control device. In the above description, "when the number of bytes of transfer data does not reach the specified number of bytes"
Means that the number of bytes of the transfer data is smaller than the specified number of bytes. If the number of bytes of the transfer data is larger than the specified number of bytes, this is an error frame. Even if the communication controller on the transmitting side transmits the digital data on the digital line 6 as it is, the communication controller on the receiving side is an error frame. Can be detected.

On the other hand, if it is determined in step ST4 that the transferred frame is an error frame, it is checked in step ST7 whether or not the transfer data is larger than a specified number of bytes. If it is not larger than the prescribed number of bytes, in step ST8 "0" data is transferred to the data input / output unit 17 to increase the number of bytes of the transfer data.
In step ST7, it is checked again whether the number of bytes of the transfer data is larger than the specified number of bytes, and this process is repeated until the number of bytes of the transfer data becomes larger than the specified number of bytes. FIG. 5 is a diagram showing an example of the operation of the transmission-side communication control device when the transmission-side communication control device has an abnormality in the transmission data frame received from the transmission-side facsimile device 1b. FIG. 3 is a diagram illustrating a configuration. As shown in FIG. 5, when the number of bytes of the transfer data reaches 261 bytes or more, the transfer data having a frame structure larger than the specified number of bytes is transferred onto the digital line 6. Is transmitted, and the ECM data transmission control operation for the frame is completed. If it is determined in step ST7 that the number of bytes of the transfer data is larger than the specified number of bytes, that is, if the number of bytes of the transfer data is larger than the specified number of bytes from the beginning, for example, 270 bytes, As mentioned this is an error frame,
Since the communication control device on the receiving side can make the determination, the communication control device on the transmitting side transmits the signal on the digital line 6 as it is,
Thereafter, the data transmission control operation is completed.

When the received communication frame has an error, the communication control device on the transmitting side changes the frame configuration of the received data to 261.
If the number of bytes is equal to or more than the byte, the data is directly transmitted to the communication control device on the receiving side, and the frame configuration of the received data is
If it is 0 byte or less, "00" is added to the frame as additional data to make it 261 bytes (or more bytes), and the data is transmitted to the communication control device on the receiving side. Even if the transmission data has a frame configuration of 260 bytes or a short frame configuration of less than 260 bytes, if the reception data has an error, the data is uniformly processed by the addition process of “00”. Is converted to a frame configuration of 261 bytes or more. Upon receiving the data having the 261-byte frame configuration, the communication control device on the receiving side recognizes the data as an abnormal frame and transmits the data to the facsimile device 1a on the receiving side via the analog line 2a.
As a result, the other party can be reliably notified that the frame is an error frame, and the other party can easily determine that the error has occurred on the analog line.

Next, the operation of the ECM data reception control processing will be described. In the flowchart shown in FIG. 3, when ECM data reception control is started, it is checked in step ST11 whether data has been received from data input / output unit 17, and if data has not been received, the process proceeds to step ST11. Repeat the check operation. If the data has been received, the data is transferred to the modem in step ST12, and it is checked in step ST13 whether or not the frame reception has been completed. In this check operation, if the frame reception has not been completed, the process returns to step ST11 to return to steps ST11 to ST11.
While the operation of step ST13 is repeated, if the frame reception has been completed, the head data of the frame received in step ST14 is "F
Check if it starts with "F" or "03". Then, the head data of the frame starts with “FF” and “03”.
If so, it is checked in step ST15 whether the number of bytes of the received data has reached the specified number of bytes, and if the number of bytes of the received data matches the specified number of bytes.
If not , in step ST16, the received facsimile 1a is transmitted as "the received frame is an error frame" and the ECM data reception control operation for the frame is completed.

The processing operations in steps ST15 and ST16 correspond to operations in which the number of bytes of a normal frame is changed to a specified number of bytes by the transmission-side communication control device. In the above operation, the transmission-side communication control device reconstructs a frame determined to be a normal frame by the transmission-side communication control device into a byte number of 260 bytes and a frame determined to be an error frame by a byte number greater than 260 bytes and transmits the frame. Therefore, the communication control device on the receiving side only needs to check the number of bytes of the frame of the received data. If the number of bytes of the received data frame does not match the specified number of bytes, it is determined that the frame is an error frame. On the other hand, step ST1
5, if it is determined that the number of bytes of the received data has reached the prescribed number of bytes, the receiving-side facsimile 1a
To the received frame is a normal frame, and completes the ECM data reception control operation for that frame.

On the other hand, regarding the frame received in step ST14, the head data of the frame is "F
If it is determined that the frame does not start with "F" or "03", the data for that frame is discarded in step ST18, and the ECM data reception control operation for that frame is completed. The head data of the frame is "FF"
The received data that does not start with “03” means, for example, data transmitted from the transmission-side communication control device as a normal frame onto the digital line 6, but data transmitted from the transmission-side facsimile device 1 b to the transmission-side communication control device. This occurs when the transfer is not in time. FIG.
FIG. 4 is a frame configuration diagram showing a state in which data composed of one frame is divided into two frames for some reason. As a result of this situation,
For example, as shown in FIG. 6, two frames having 200 bytes in the first half and 60 bytes in the second half may be formed as shown in FIG. In such a case, the communication controller on the transmitting side conventionally transmits the frame as a normal frame even though the frame itself is an error frame, so the communication controller on the receiving side receives the frame as a normal frame. However, the communication controller on the receiving side according to the present embodiment discards the data of the latter half frame whose head data does not start with “FF” or “03” in step ST18 as described above. Never receive it. Incidentally, for a 200-byte frame corresponding to the first half of the data, it is determined that the number of bytes of the frame does not match the specified number of bytes in step ST15 because the number of bytes is 200 bytes.
At 16, it is transmitted to the receiving facsimile 1 a as an error frame. In this way, when data that should be transmitted as one frame is divided for some reason, the first half of the frame is transmitted to ensure continuity of communication, prevent unnecessary communication, and improve continuity of communication. If an error frame is sent to the receiving facsimile machine to secure, unnecessary frames are discarded,
Useless communication can be prevented. Therefore, in the present embodiment, inconvenience such as a reception error when one frame originally becomes two frames does not occur.

[0030]

As described above, according to the present invention,
First and second input / output means for performing facsimile communication with a communication control apparatus via a transmission line and a reception-side facsimile terminal via an analog line, respectively, and control for controlling input / output of the first and second input / output means Control means, when the data from the first facsimile terminal does not reach the predetermined number of bytes, zero data is added to make the frame into an HDLC frame of the predetermined number of bytes and transmitted to the digital line. The communication control device can determine whether the frame is normal or abnormal by checking whether the number of bytes of the frame of the received data matches the specified number of bytes. The effect that the other communication control device can reliably distinguish the frame which was a frame from an abnormal frame such as a divided frame. It is obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a communication control device according to the present invention.

FIG. 2 is a flowchart for explaining a transmission control operation when performing ECM data facsimile communication by HDLC between a transmission side facsimile and a reception side facsimile in the embodiment.

FIG. 3 is a flowchart illustrating a reception control operation when performing ECM data facsimile communication by HDLC between a transmitting facsimile and a receiving facsimile in the embodiment.

FIG. 4 is a frame configuration diagram illustrating a state in which the number of bytes of transmission data is corrected to a specified number of bytes in one frame in the embodiment.

FIG. 5 is a frame configuration diagram showing a frame generated by a transmission-side communication control device when a frame of transmission data received from a transmission-side facsimile apparatus has an error in the embodiment.

FIG. 6 is a frame configuration diagram showing a state in which data that was originally one frame for some reason is divided into a plurality of frames in the embodiment.

FIG. 7 is a block diagram schematically showing a communication system of a system in which data is framed in an HDLC mode for communication.

FIG. 8 is a frame configuration diagram of normal data transmitted and received in the HDLC communication system.

FIG. 9 is a short frame configuration diagram of normal data transmitted and received in the HDLC communication system.

FIG. 10 is a frame configuration diagram of abnormal data transmitted and received in the HDLC communication system.

[Explanation of symbols]

 1a, 1b Facsimile machine 2a, 2b, 20 Analog line 3a, 3b Switch 4a, 4b TDM device (communication control device) 5a, 5b, 13 FAX modem 6, 21 Digital line 7 Communication control unit 11 Communication control unit 12 Codec unit 14 Control unit 15 ROM 16 RAM 17 Serial input / output unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-5-14668 (JP, A) JP-A-4-109762 (JP, A) JP-A-4-170243 (JP, A) JP-A-6-106 318965 (JP, A) JP-A-58-165446 (JP, A) JP-A-7-111571 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 1/32-1 / 36 H04N 1/42-1/44

Claims (7)

(57) [Claims] An HDLC via a digital line to a first input / output means for facsimile communication with a first facsimile terminal 1b via an analog line and a data terminal 4a for facsimile communication with a second facsimile terminal 1a via an analog line. A second input / output unit for performing data communication in a frame, and a control unit for controlling input / output between the first input / output unit and the second input / output unit, wherein the control unit is configured to transmit data from the first facsimile terminal 1b. A communication control device for transmitting the data to a digital line with a data length longer than a predetermined byte when the error frame is an error frame. 2. A first facsimile terminal 1b and an analog terminal
First input / output means for performing facsimile communication via a line,
2 Facsimile by facsimile terminal 1a and analog line
Digital line for data terminal 4a for millimeter communication
2nd facsimile communication with HDLC frame via
Input / output means, input of the first input / output means and second input / output means
Control means for controlling the output, the control means comprising:
The number of bytes of data from one facsimile terminal 1b is predetermined
If the number of bytes is not reached, zero data is added and a predetermined byte is added.
Number of HDLC frames and send them to the digital line.
That one, if the data is an error frame from the first facsimile terminal 1b <br/> communication control apparatus and transmits to the digital line and the data on the data length of more than a predetermined number of bytes. 3. A first input / output means for performing facsimile communication with the first facsimile terminal 1a via an analog line;
Second input / output means for performing data communication with the facsimile terminal 1b via a digital line with respect to the data terminal 4b which performs facsimile communication with the facsimile terminal 1b, and control means for controlling input / output between the first input / output means and the second input / output means; When the control means determines that the data from the second facsimile terminal 1b has not reached the predetermined number of bytes,
A communication control device characterized in that even if the CRC in the frame is normal, the frame is rewritten as abnormal and transmitted to the first facsimile terminal 1a . 4. A first input / output means for performing facsimile communication with the first facsimile terminal 1a via an analog line;
Second input / output means for performing data communication with the facsimile terminal 1b via a digital line with respect to the data terminal 4b which performs facsimile communication with the facsimile terminal 1b, and control means for controlling input / output between the first input / output means and the second input / output means; The control means detects whether or not there is a predetermined data pattern at the head of data received from the data terminal 4b of the second facsimile terminal 1b , and if there is a data pattern, the received data has a predetermined number of bytes. Is determined, and if the predetermined number of bytes is not reached, C in the frame is determined.
A communication control device wherein even if the RC is normal, it is rewritten as abnormal and transmitted to the first facsimile terminal 1a . 5. A first input / output means for performing facsimile communication with the first facsimile terminal 1a via an analog line;
Second input / output means for performing data communication with the facsimile terminal 1b via a digital line with respect to the data terminal 4b which performs facsimile communication with the facsimile terminal 1b, and control means for controlling input / output between the first input / output means and the second input / output means; The control means detects whether or not a predetermined data pattern is present at the beginning of data received from the data terminal 4b of the second facsimile terminal 1b. If there is no data pattern, the control means detects an error frame regardless of the content of the CRC. A communication control device characterized in that the communication control device discards the information when it is determined that the communication control device is in use. 6. The control means comprises a second facsimile terminal 1b.
Detecting whether there is a predetermined data pattern at the beginning of the data received from the data terminal 4b, and if there is no data pattern, determining that the frame is an error frame regardless of the content of the CRC and discarding the frame. The communication control device according to 3 or 4 . 7. A predetermined number of bytes, the communication control device according to any one of claims 1 to 6, characterized in that the number of bytes constituting one frame of data in HDLC mode.