JPH0591278A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To quickly transmit/receive image information by accumulating the times of transmission of a re-sending request signal and forcedly transmits a message confirmation signal before the times of the transmission reaches a prescribed number of times. CONSTITUTION:After transmitting a re-sending request signal PPR, a CPU adds one to an accumulated number of times F of the re-sending request signal and when the value reaches the prescribed number of times, forcedly transmits a message confirmation signal MCF regardless of the presence or absence of an error. The signal PPR is used for detecting the error of a facsimile message and requesting of re-sending the message, and these operations are executed in a CPU 91 of a communication part. When the signal MCF is transmitted, the measure of changing a transmission mode taken by a calling station is suppressed and delaying of transmission speed and interruption of transmission are avoided. Accordingly, the increase of the time and cost of communication due to an error correction processing is suppressed without causing disability of transmission/receiving even when the receiving of the message is faulty. Thus, the transmission/receiving can quickly be performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an ECM (error correction mode).
The present invention relates to an improvement of a facsimile device having a function of Error Correction Mode).

[0002]

2. Description of the Related Art Conventional digital facsimile standards (G3
In the standard), the transmitting side frames the encoded data of the image information in units of 256 or 64 octets, and transmits a maximum of 256 frames as one block in order for each block. Further, a redundant bit for error correction is added to each frame so that the receiving side can check the error.

Every time one block is received, the receiving side checks the presence or absence of an error for each frame, and sends back a resend request for the frame in which the error has occurred. The transmitting side checks again the received retransmission request block for an error, and retransmits the result to the receiving side. in this way,
When an erroneous frame occurs on the receiving side, the transmitting side collectively retransmits the frames in the form of a retransmission block.

FIG. 5 shows an example of this error correction processing. This example is a case where the communication condition is recognized to be poor by the first transmission / reception of the training signal, and after the reception preparation confirmation signal CFR is transmitted from the reception side, the transmission side transmits a facsimile message (first one block). ) Is transmitted at 2400 bps, and when an error occurs on the receiving side, a retransmission request signal PPR is transmitted from the receiving side, and the transmitting side sends a facsimile message (retransmission block) a total of three times each time PPR is received.
Then, in response to the fourth retransmission request signal PPR, the transmitting side issues a retransmission end instruction signal EOR to terminate the transmission of this block, and further issues a line disconnection instruction signal DCN to disconnect the line.

6 and 7 show another example of this error correction processing. 6 shows the front stage of the error correction process, and FIG. 7 shows the rear stage of the error correction process. This example is the case where the communication condition is confirmed to be good by the first transmission / reception of the training signal, and after the reception preparation confirmation signal CFR is transmitted from the reception side, the facsimile message (the first one block is transmitted from the transmission side). ) Is transmitted at 4800 bps, and when an error occurs on the receiving side, the retransmission request signal PP is sent from the receiving side.
When R is transmitted, the transmitting side retransmits the facsimile message (retransmission block) three times each time the PPR is received, and the transmitting side sends 24 times the retransmission request signal PPR for the fourth time.
When the transmission speed is reduced to 00 bps, the retransmission request signal PPR is transmitted three times each time the retransmission request signal PPR is transmitted, and when the retransmission request signal PPR is still transmitted, the retransmission end command signal EOR is sent.
To terminate the transmission of this block and shift to the transmission of the next block.

[0006]

Generally, since image information has a large degree of redundancy, it is useful for many applications to receive it even if the image quality is somewhat poor. However, as described above, the image information is transmitted and received several times. After that, if the line is disconnected, there is a problem that the image information cannot be obtained at all just by spending time and money. In addition, when high speed transmission / reception of 4800 bps and low speed transmission / reception of 2400 bps are performed, the time required for transmission / reception of one block becomes extremely long, which is a problem in terms of time and cost.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a facsimile apparatus having an error correction processing function (ECM function) capable of quickly transmitting and receiving image information. ..

[0008]

The facsimile apparatus of the present invention retransmits retransmission request data in response to a retransmission request signal from the receiving side, and the cumulative number of times the retransmission request signal is received reaches a predetermined number. In this case, it is connected to a calling station that changes the transmission mode of the image information. If the received data from this calling station is bad, the resend request signal is sent and the received data is good. In this case, in a facsimile apparatus that transmits a message confirmation signal, the number of times the retransmission request signal is transmitted is accumulated, and the message is transmitted before the accumulated number of transmissions reaches the predetermined number.
A message confirmation signal forcibly transmitting means for forcibly transmitting the message confirmation signal is provided.

Here, changing the transmission mode of image information means
Refers to slowing the transmission speed or stopping transmission.

[0010]

The called station, that is, the facsimile machine on the receiving side,
If an error occurs in the facsimile message transmitted from the transmitting side and an error occurs, a retransmission request signal is issued and retransmission request data is obtained until the error is resolved. The calling station, that is, the transmitting side changes the transmission mode of the image information when the cumulative number of receptions of the retransmission request signal reaches a predetermined number, and slows down the transmission speed or cancels the transmission.

In particular, the message confirmation signal forced transmission means of the present invention forcibly transmits the message confirmation signal before the cumulative number of times the retransmission request signal is transmitted reaches the predetermined number of times, and the transmission by the calling station is performed. Mode change measures are suppressed to prevent the transmission speed from slowing down or transmission being stopped.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the facsimile apparatus of the present invention. The facsimile 11 is connected to the handset 3 and the wireless device 2. The facsimile 11 includes an operation unit 7 for setting functions such as transmission and reception, a communication unit 9 for transmitting / receiving facsimile data to / from the wireless device 2,
A reading / recording unit 8 for printing the image data decoded by the communication unit 9 and for reading an original to be transmitted; a line control unit 5 for switching the line based on the usage states of the communication unit 9 and the handset 3; The system control unit 6 controls each functional block.

The signal received by the wireless device 2 is the reception line 2aR.
Is sent to the changeover switch 5f in the facsimile 11, and the changeover switch 5f connects this reception line 2aR and the reception line 9aR to the communication section 9 of the facsimile (that is, the facsimile use state) or the reception line 2aR. Whether the connection with the receiving line 3aR of the handset 3 is connected (that is, the state of use of the mobile phone) is switched and controlled. Further, the changeover switch 5e in the facsimile 11 connects the transmission line 2aT from the facsimile 11 to the wireless device 2 and the transmission line 9aT of the communication unit 9 (that is, the facsimile use state) or the transmission line of the wireless device 2. 2aT and the transmission line 3aT of the handset 3 are connected to each other (that is, the state of use of the mobile phone) and controlled. As a result, the wireless device 2 and the handset 3 can communicate with each other when using a car phone, while the wireless device 2 and the communication unit 9 of the facsimile 11 can transmit and receive when using a facsimile.

The line control unit 5 has a CPU and is connected to the handset 3 and the wireless device 2 via a serial data line 5d so as to be capable of bidirectional communication, and is bidirectionally connected to the system control unit 6 via a control signal line 6a. Communication Connected for communication. The line controller 5 monitors the serial data from the wireless device 2 and the handset 3 through the serial data line 5d, and sends various messages (serial data) concerning the communication state from the wireless device 2 and the handset 3. It reads and transmits it to the system control unit 6 through the control signal line 5a, or sends serial data to the wireless device 2 or the handset 3 to support facsimile communication. Furthermore,
The line control unit 5 controls opening / closing of the switch 5e via the control line 5bT and opening / closing of the switch 5f via the control line 5bR.

The system control unit 6 has a CPU, and the operation unit 7 and the control signal line 6a, the reading and recording unit 8 and the control signal line 6b, and the communication unit 9 and the control signal lines 6c and 6d are used for two-way communication. The facsimiles 11 are connected so that they can cooperate with each other in the facsimile 11. The operation unit 7 is an operation display unit for inputting an operation signal of the facsimile 11 and displaying the state thereof. The operation unit 7 sends operation signal data to the system control unit 6 and displays the state of the facsimile 11 from the system control unit 6. Receive data.

Next, the internal structure of the communication section 9 constituting the forced transmission means, the received signal level detection means, and the forced transmission prohibition means in the present invention will be described with reference to FIG. Communication unit 9
Has a CPU 91, a modem 92, a code decoder 93, a memory 94, and a data control unit 95. The CPU 91 has a control signal line 6c, a system control unit 6, a control signal line 9b, a modem 92, and a control signal. Code decoder 9 by line 9c
3 and the data is exchanged, and further, the facsimile data is received from the wireless device 2 through the transmission line 9aR and the reception line 9aR is received.
Facsimile data is transmitted to the wireless device 2 through aT. The reception line 9aM sends information from the wireless device 2 to the communication unit 9 during a call.

The modem 92 demodulates the received signal (analog signal) received by the radio 2 and input through the receiving line 9aR, and the demodulated coded data signal is passed through the signal line 9d. And is output to the code decoder 93 for decoding. The modem 92 also modulates the encoded data encoded by the encoder / decoder 93 and outputs it to the wireless device 2 via the transmission line 9aT. Here, the CPU 91 takes in the demodulated predetermined facsimile information through the modem 92, modulates the necessary facsimile information by the modem 92, and transmits the modulated facsimile information to the facsimile of the other party.

The code decoder 93 decodes the coded data input from the modem 92 into image data, and the image data input from the data control unit 95 through the data line 9f. Is encoded into encoded data. The decoding and coding operations of the code decoder 93 are performed by the control signal line 9c.
Is controlled by the CPU 91. Data control unit 9
Reference numeral 5 indicates the image data decoded by the code decoder 93 based on the control signal output from the system control unit 6 through the control signal line 6d, and outputs or outputs the image data to the reading / recording unit 8 via the communication line 8a. The image data output from the recording unit 8 is output to the code decoder 93. The signal output from the code decoder 93 to the CPU 91 is the code decoder 93.
Is a signal for informing the CPU 91 of the decoding or encoding status of (for example, a signal for informing of which row the encoding is completed). Further, the data control unit 95 is controlled by the system control unit 6 to send the encoded data of the memory 94 to the code decoder 93 through the data line 9e to decode it and output it to the reading and recording unit. The coded data from the code decoder 93 is stored in the memory 94 via the data line 9e.
Here, the data stored in the memory 94 is encoded data, and the input / output data of the reading / recording unit 8 is image data. Therefore, for example, the coded data received by the wireless device 2 and modulated / demodulated by the modem 92 is decoded by the code decoder 93 into image data when output to the reading / recording unit 8, and then stored in the memory 94. In the case of storage, the coded data is not decoded by the code decoder 93 and stored as coded data. Therefore, when the image data corresponding to the transmission original read by the reading / recording unit 8 is temporarily stored in the memory 94, the data control unit 95 reads the reading / recording unit 8 based on the control signal from the system control unit 6. The image data from is encoded by the encoder / decoder 93 and the encoded data is output to the memory 94.

Next, the operation of the above device will be described.
Normally, the changeover switch 5f connects the reception line 2aR and the reception line 3aR of the handset 3, and the changeover switch 5e connects the transmission line 2aT and the transmission line 3aT of the handset 3 (that is, the mobile phone use state). ). Then, the line control unit 5 makes the serial data line 5
The wireless device 2 and the handset 3 are monitored through d. This enables a call between the wireless device 2 and the handset 3. The call state is controlled by the downlink serial data sent from the wireless device 2 to the handset 3 and the upstream serial data sent from the handset 3 to the wireless device 2 through the serial data line 5d.

The transmission operation of the facsimile 11 will be described below. During transmission of the facsimile 11, after the connection with the telephone line of the other side is secured by operating the handset 3, the changeover switches 5e and 5f are switched to enable transmission / reception between the wireless device 2 and the communication section 9 of the facsimile 11. Here, when the operator sets a document and instructs the transmission by the operation unit 7, the image data of the transmission document is photoelectrically converted by a line sensor (not shown) of the reading and recording unit 8. The photoelectrically converted image data is output to the communication section 9 via the signal line 8a and encoded by the code decoder 93 under the control of the system control section 6. This encoded data is transmitted by the wireless device 2 to the destination facsimile via the modem 92 and the transmission lines 9aT and 2aT.

Next, the receiving operation of the facsimile 11 will be described. A tone signal is sent from the base station through the wireless device 2 to enable communication with the handset 3, and then a tone signal indicating a facsimile signal is transmitted from the base station through the wireless device 2 to the line controller 5 Then, the line control unit 5 switches the changeover switches 5e and 5f to the side of the communication unit 9 of the facsimile 11 to enable transmission / reception between the wireless device 2 and the communication unit 9 of the facsimile 11.

After that, the communication section 9 of the facsimile 11 receives the image data from the base station through the wireless device 2. That is, the image data sent through the reception signal lines 2aR and 9aR is sent to the modem 92 and demodulated, and then the receiving method preset by the operation unit 7 (that is, the printing by the reading / recording unit 8 is performed. Output or memory 9
4), the data is decoded by the code decoder 93 and then output to the reading / recording unit 8 through the data control unit 95, or is not decoded and stored in the memory 94 through the data control unit 95. Is output to. The image data output to the reading / recording unit 8 is printed out by a printing device (not shown) in the reading / recording unit 8. On the other hand, the coded data stored in the memory 94 is printed out after being decoded by the operator instructing the printout from the operation unit 7.

The error correction process, which is the main part of this embodiment, will be described below with reference to the flow chart of FIG. 3 and the signal diagram of FIG. This flow chart is the CP of the communication unit 9.
It is executed by U91. It should be noted that the correction subroutine shown in FIG. 3 is described as a single routine for the sake of simplification of description, but it is actually carried out at regular intervals together with the main routine and other subroutines. ing.

When a calling tone signal CNG is transmitted from a calling station, that is, a facsimile machine (not shown) on the transmitting side, the called station, that is, the facsimile machine 1 of this embodiment, responds to it.
1 is a called station identification signal CED and a digital identification signal DIS
To the calling station, in response to which the calling station transmits a digital command signal DCS, and when the called station receives this DCS, it prepares to receive a training signal. Then, the calling station
When the training check signal TCF is transmitted at 4800 bps, the called station receives it, and when the reception result of the training signal is good, it transmits the reception preparation confirmation signal CFR, that is, the serial data indicating that the reception result is good.

As a result, the calling station sends a training signal followed by the first block of the facsimile message 48.
Transmission at 00 bps and then the block end signal PPS
To notify that one block has been transmitted.
The called station waits until the block end signal PPS is received (100), and the CP of the communication unit 9 is received by the PPS reception.
U91 detects an error in the facsimile message based on the redundant bit for error detection built in the received block (101).

Next, the presence or absence of an error is checked (102), and if no error is found, the process proceeds to step 112 to send a message confirmation signal MCF, while if there is an error, a retransmission request signal is sent as shown in FIG. A PPR is issued (104), and the calling station retransmits a block composed of erroneous frame groups in the PPR, a training signal to the called station, a retransmit block composed of erroneous frame groups in the PPR, and a block end signal PPS. To send.

After transmitting the retransmission request signal PPR (104), the CPU 91 adds 1 to the cumulative number of retransmission requests F (1
08), it is checked whether or not the current cumulative number of retransmission requests F has reached 3 times (110), and if not, step 10
Error detection is performed again by returning to 0, and if the number of times reaches three times, the process proceeds to step 112, and a message is displayed regardless of whether there is an error.
The confirmation signal MCF is transmitted, and this error correction processing subroutine is terminated.

Therefore, the steps 110 and 112 constitute the message confirmation signal forced transmission means in the present invention. In this way, the third retransmission request signal PPR
Is not transmitted, the calling station decreases the transmission speed (Fig. 6,
(See Fig. 7) and transmission stop (See Fig. 5)
Transmission / reception delay and transmission / reception failure due to this will not occur.

[0029]

As described above, the facsimile apparatus of the present invention transmits a message confirmation signal to the transmitting side when the cumulative number of times of reception of the retransmission block of the facsimile message reaches the predetermined number. Since it is equipped with a message confirmation signal compulsory transmission means, even if the message reception is bad, transmission / reception cannot occur, and the increase in communication time and cost due to error correction processing is suppressed, and image information is transmitted / received quickly. obtain.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention,

FIG. 2 is a block diagram showing an internal configuration of a communication unit of the above embodiment,

FIG. 3 is a flowchart showing an error correction processing subroutine of the above embodiment,

4 is a signal line diagram showing an example of error correction processing by the flow chart of FIG.

FIG. 5 is a signal diagram showing an example of conventional error correction processing.

FIG. 6 is a signal diagram showing a front stage of another example of the conventional error correction processing;

FIG. 7 is a signal line diagram showing the latter stage of another example of the conventional error correction processing shown in FIG.

[Explanation of symbols]

2 wireless device 3 handset 5 line control unit 9 communication unit (message confirmation signal forced transmission means) 10 system control unit 11 facsimile (facsimile device)

Claims (1)

[Claims] 1. A transmission mode of the image information when the retransmission request data is retransmitted in response to a retransmission request signal from the receiving side and the cumulative number of receptions of the retransmission request signal reaches a predetermined number. Connected to the calling station that changes the
In a facsimile machine that sends the resend request signal when the data is bad, and the message confirmation signal when the received data is good, the number of times the resend request signal is transmitted is accumulated, and the accumulated number of transmissions is accumulated. Is provided with a message confirmation signal forcibly transmitting means for forcibly transmitting the message confirmation signal before the number of times reaches the predetermined number.