JPH10224589A - Facsimile communication equipment and its method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain excellent transmission efficiency and noise resistance by switching a 1st communication mode to a 2nd communication mode when the transmission of data by the 1st transmission mode is disabled during the transmission of the data to an opposite party and resending the data by the 2nd transmission mode. SOLUTION: When transmission is disabled on the way during the period of ECM transmission by 256-byte frame size e.g. a main control part 106 stores the destination of transmission, a communication type, frame size, and a communication result in a communication control data memory 108. When the preceding communication type is a 256-frame ECM communication type, a communication type selection part 109 selects a 64-frame ECM communication type. The main control part 106 receiving the selection result controls a network control part 105, temporarily disconnects a connected call and outputs a communication type switching command to an MODEM control part 103. Thereby an MODEM 104 is switched to the 64-frame ECM communication type. Then the control part 105 reconnects the same opposite party by using a destination number stored in the memory 108 and retransmits the connected call by the 64-frame ECM communication type.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a facsimile apparatus, and more particularly to an ITU (International Telecommunication).
Union) ECM method (Error Correction Mod)
The present invention relates to a facsimile communication apparatus and method using e).

[0002]

2. Description of the Related Art The ECM system is an error correction system in facsimile communication. When coded image data is transmitted in a frame format and an error is detected on the receiving side, the frame number on which the error has occurred is transmitted from the receiving side after data transmission is completed. Side to request retransmission of the frame. Generally, a frame size of 256 bytes (256-byte frame communication) is used, but the ECM method can change the frame size.

A facsimile communication system utilizing this frame size changing function to reduce the probability of error occurrence by changing the frame size when retransmitting data in which an error has occurred is disclosed in JP-A-3-40557. Have been. For example, if the frame size is set to 64 bytes and transmitted, the frequency of frame errors is theoretically one-fourth that of 256-byte frame communication in a line where noise is generated periodically. Similarly, it will decrease. Therefore, on a line in which noise is generated periodically, 6 lines are required in the 256-byte frame communication.
The 4-byte frame communication has improved noise resistance.

[0004]

However, when 64 byte frame communication is performed on a line in which no transmission error occurs, a problem arises in that the transmission efficiency is reduced due to division loss as compared with 256 byte frame communication.

An object of the present invention is to provide a facsimile communication apparatus and method which are excellent in transmission efficiency and noise resistance.

Another object of the present invention is to provide a facsimile communication apparatus and method capable of performing transmission with an appropriate frame size according to line characteristics.

[0007]

SUMMARY OF THE INVENTION A facsimile communication apparatus according to the present invention includes a communication mode using a first frame size (hereinafter, a first communication mode) and a communication mode using a second frame size shorter than the first frame size. A communication means capable of mode switching between the first communication mode and the second communication mode. If communication is not established due to line characteristics while data is being transmitted to the other party in the first communication mode, the communication means is switched to the second communication mode. And control means for switching to a communication mode and retransmitting to the other party.

Further, in the facsimile communication method according to the present invention, when transmission of transmission data is started, a communication mode with a first frame size (hereinafter referred to as a first communication mode) is set, and data is transmitted in the first communication mode. If communication fails due to line characteristics during transmission to the other party, communication control information of the communication is stored, and the first communication control information is stored based on the communication control information.
Switching to a communication mode using a second frame size shorter than the frame size (second communication mode) and performing retransmission to the destination.

According to the present invention, when the first communication mode is not established due to the line characteristics, the second communication mode is automatically set upon retransmission.
The communication mode is selected. Since the second communication mode transmits with a frame size shorter than the first frame size, retransmission errors can be reduced, and facsimile transmission with excellent transmission efficiency and noise resistance can be realized.

[0010]

FIG. 1 is a schematic block diagram showing an embodiment of a facsimile communication apparatus according to the present invention. Although the facsimile communication device can transmit and receive data, data transmission will be described here. The transmission data stored in the transmission / reception data memory 101 is modulated by the modem 104 under the control of the communication control unit 102 and the modem control unit 103, and the modulated signal is transmitted to the communication line through the network control unit 105. The modem 104 according to the present embodiment supports both the 256-frame ECM communication mode and the 64-frame ECM communication mode, and can operate in one of the communication modes in accordance with a switching command from the modem control unit 103.

The main control unit 106 has a program memory 10
7, the control of the entire facsimile machine is executed. The control program stored in the program memory 109 includes the communication program according to the present embodiment, and the main control unit 106 selects a communication mode using the communication control data memory 108 and the communication method selection unit 109 as described later. The modem control section 103 controls the modem control section 103 in accordance with the selection result to execute mode switching between the 256-frame ECM communication mode and the 64-frame ECM communication mode. Note that the communication method selection unit 109 can be realized by a program, as described later.

FIG. 2 is a flowchart showing a communication operation in the present embodiment. First, when transmitting for the first time, the main control unit 106 sets the modem 104 to 256 frames E
The communication mode is set to the CM communication mode (S201), and the communication control unit 102
, Sequentially reads out the transmission data stored in the transmission / reception data memory 101 and performs ECM transmission with a frame size of 256 bytes (S202). If all the transmission data is transmitted without error and the 256-frame ECM communication is established (YES in S203), the process ends normally.
On the other hand, when the line characteristics are deteriorated and the 256 frame communication is not established in the middle, for example, when the communication is abnormally terminated due to an error retrain over related to a retransmission error (S203).
NO), the main control unit 106 determines the transmission destination (telephone number or the like), communication method (here, ECM), frame size (here, 256 bytes), and communication result (here, N
G: not established) is stored in the communication control data memory 108 (S204).

Subsequently, the main control unit 106 calls a communication system selection program and selects a communication system. That is,
The communication method selection unit 109 checks whether or not to retransmit the error data (S205), and when retransmitting, checks whether or not the previous communication method was ECM communication (S206). If the previous time is ECM communication (S206
YES), it is checked whether the frame size at that time is 256 bytes or 64 bytes (S207). Last time was 25
64 frame ECM if 6 frame ECM communication system
The communication method is selected, and the result of the selection is returned to the program of main control unit 106. Upon receiving the selection result, the main control unit 106 controls the network control unit 105 to temporarily disconnect the connection call, and outputs a communication system switching command to the modem control unit 103. This allows the modem 104 to have a 64-frame EC
The system is switched to the M communication system (S209). Subsequently, the same connection is made again using the destination number stored in the communication control data memory 108.
Retransmission is performed in the M communication system (S210). In addition,
Whether the previous time is not ECM communication (NO in S206) or 64
In the case of the frame ECM communication method, retransmission is performed without switching the communication method.

As described above, 256 lines depend on line characteristics.
When frame ECM communication is not established, a 64-frame ECM communication method is automatically selected at the time of retransmission, retransmission errors can be reduced, and facsimile transmission excellent in transmission efficiency and noise resistance can be realized. it can.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram showing an embodiment of a facsimile communication apparatus according to the present invention.

FIG. 2 is a flowchart illustrating a communication operation according to the embodiment.

[Explanation of symbols]

 101 Transmission / Reception Data Memory 102 Communication Control Unit 103 Modem Control Unit 104 Modem 105 Network Control Unit 106 Main Control Unit 107 Facsimile Control Program Memory 108 Communication Control Data Memory 109 Communication System Selection Unit

Claims (5)

[Claims] 1. An ECM method (Error Correction Mode)
In a facsimile communication apparatus utilizing the communication method, a communication mode between a communication mode with a first frame size (hereinafter, a first communication mode) and a communication mode with a second frame size shorter than the first frame size (a second communication mode) Communication means capable of mode switching in the first communication mode, and when communication becomes unsuccessful due to line characteristics while data is being transmitted to the other party in the first communication mode, the communication means is switched to the second communication mode to the other party. A facsimile communication apparatus comprising: a control unit for performing retransmission. 2. The control means has a memory for storing communication control information of the communication when the communication is not established,
2. The communication device according to claim 1, wherein, when the communication is the communication in the first communication mode, the communication means is switched to the second communication mode and retransmitted to the other party according to the communication control information. Facsimile communication device. 3. An ECM method (Error Correction Mode)
In the facsimile communication method using the communication mode, a communication mode with a first frame size (hereinafter, a first communication mode) is set when transmission of transmission data is started, and data is being transmitted to a destination in the first communication mode. When communication becomes unsuccessful due to line characteristics, communication control information of the communication is stored, and a communication mode (second communication mode) in a second frame size shorter than the first frame size is stored based on the communication control information. And performing retransmission to the destination by switching to facsimile communication. 4. The facsimile communication apparatus according to claim 1, wherein the first frame size is 256 bytes, and the second frame size is 64 bytes. 5. The facsimile communication method according to claim 3, wherein the first frame size is 256 bytes, and the second frame size is 64 bytes.