JPS62210781A - Communication error processing system for facsimile - Google Patents

Abstract

PURPOSE:To always send the accurate picture information to a receiver with a simple and steady method, by constructing a system so that a transmission side stops a transmission at every transmission of one block share of memory, and waits a signal from a reception side, and when a transmission error is generated, it retries the transmission from the line of the block where the error is generated. CONSTITUTION:The transmission side transmits all of the contents of the memories at every line starting from the k-th line stored at one block of a RAM12, and after completing the sending of all of the contents of the memories in one block, it waits the signal from the reception side. And the reception side receives the picture signal sent from the transmission side at every line, and decides the presence/absence of a reception error. When the reception error exists, a recording after the line where the error is generated, is interrupted, at the same time, the number of reception lines sent to the transmission side is set as one preceding number of the number where the error is generated. Thus, the transmission side stops the transmission at every transmission of one block, and waits the signal from the reception side, and when the signal is an error signal, it starts the transmission again from the number of lines in which one is added on the number of lines where one block is received normally, that is, the number of lines where the error is generated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication error processing system in facsimile, and more particularly to an improvement in a system for retransmitting error image information in a half-duplex communication system.

[Prior art I] When transmitting an A4-sized document, the number of pixels in one line is set at 1728 dots according to CCITT recommendations. However, if the telephone line is in bad condition, the number of dots other than 1728 may be transmitted to the receiver. may be reached. Conventionally, when such a transmission error occurs, the following various processing methods have been adopted.

(1) The receiver ignores the error and prints as is.

(b) In the case of full-duplex communication, when the receiver detects an error, it immediately notifies the transmitter of the occurrence of the error, and at the same time notifies the location of the error.The transmitter transmits again from the location where the error occurred.

(3) In the half-duplex communication system, when a receiver detects an error, it regards the line with the error as the same as the previous line and prints it.

However, according to (1), incorrect image information will be printed as is. (B) is a full-duplex system, which makes the I device expensive. Also, (3) has drawbacks such as incorrect image information being printed.

[Problems to be Solved by the Invention] As mentioned above, according to the conventional processing method, if error handling is to be performed reliably, the equipment becomes expensive, and if the equipment is inexpensive, error handling becomes inappropriate. The configuration is also simple in dealing with image information transmission errors.

cannot be dealt with reliably.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a communication error processing method for facsimile that is capable of dealing with transmission errors of image information in a simple and reliable manner despite using a half-duplex communication method. The goal is to provide the following.

[Means for Solving the Problems] The communication error processing method of the present invention divides a document into blocks and stores image signals read from each block in an image signal memory provided on the transmitting side each time. Thereafter, the stored image signals are sequentially read line by block in units of blocks and transmitted to the receiving side.

On the receiving side, the presence or absence of a transmission error is detected every time one line picture signal is received, and if no transmission error is found, that one line is recorded and the number of recorded normal lines is stored. On the other hand, when a transmission error is detected, the recording of the line after that line is reserved, and the transmission error and the number of normal lines are sent to the transmission side after the transmission of the block currently being transmitted is completed.

The transmitting side, which has received the transmission error and the number of normal lines, reads the image signal again from the block where the transmission has been completed and retransmits the image signal from the number of lines obtained by adding 1 to the number of normal lines.

[Operation] Even if the receiving side detects a transmission error during reception, the transmitting side does not stop transmission, but continues transmission until all of the image signals for one block stored in the memory have been sent out, and then It becomes a holding state. The receiving side sends an option code indicating an error to the transmitting side in this holding state, and by interpreting this code, the transmitting side repeats the transmission from the line number where the error occurred in the block.

On the other hand, when the receiving side detects an error, even if it continues to receive image signals after the detection, recording after the line where the error occurred is interrupted, and when an error-free image signal is sent again. The interruption is canceled and the remaining recording is performed.

In order to enable such communication, it is necessary that the transmitter side is equipped with an image signal memory having a capacity of at least one block.

[Example] An example of the present invention will be described below based on FIGS. 1 and 2.

FIG. 2 shows an example of a facsimile apparatus for implementing the communication error processing method in a facsimile according to the present invention. 1 is an operation panel, 2 is a modem, 3 is a network control unit, 4 is a telephone,
5 is a printer, 6 is a reading device, 7 is a document detection sensor, 8
is Ilo, 9 is ROM, 10 is RAM, and 11 is CPU. Further, 12 is an image signal RAM for storing image signals read from the reading bag @6. The image signal RAM 12 must be included in at least the transmitter.

Next, an example of a communication error processing method using the above device will be described.
The symbols used in Figure B will now be explained.

CNG: Ring tone CED: Called station identification (indicates that the line is connected) NSF: Non-standard equipment 1 (indication of optional function) C8■
: Called station identification (displays telephone number, etc.) Dis: Digital identification signal (displays CCt T T standard) NSS: Non-standard equipment settings (displays optional functions) TSI: Transmitting station identification OCS: Digital command signal (CGIT standard) (Display) TCF = Training check (line check.

Communication speed setting) CFR: Reception standard confirmation MPS: Multi-page signal (displays next page available) pps:
Divided page signal (indicates that there is remaining data for pages that could not be stored in one block) EOP: End of procedure (displays no next page) MCF: Message confirmation DCN: Line disconnection command PPP: Transmission error signal L : Number of reception lines in the receiver K : Number of transmission lines in the transmitter S : RA for retransmission signals when a transmission error occurs
For example, M12 stores image signals for one block, which are divided into blocks for each page of a standard manuscript. When data for one page of the original overflows from one block, it is divided into two blocks and stored. The following table generally shows the signal exchange between the transmitter TX and the receiver 111RX when a transmission error occurs during the transmission of the image signal stored in the image signal RAM 12 in this manner. ′
Here, a transmission error occurs in the 2nd negative rfXm of 3 pages.

To explain this, in FUE, the pre-communication procedure starts with the ring tone CNG and ends with the reception preparation value fi1CFR.
Training will take place. In this pre-communication procedure, the communication error handling method according to the present invention is set between the transmitter and the receiver using both the non-standard device NSF and non-standard device setting NSS signals.

In phase (2), the first negative image signal is normally received and communication is performed in units of blocks ending with message confirmation IMCF.

Table: Transmission error Temporary signal exchange 2 In the negative sending phase (■), the receiver RX detects a transmission error and transmits the transmission error signal PPR to the transmitting ITX at the end of the transmission of the relevant block. . This PPR
contains information on the number of lines that the receiver has successfully received within the page.

In phase (2), the transmitter 11TX that has received the transmission error signal PPR performs retransmission of the second negative number of lines starting from the number of lines that could be received normally plus one.

Then, after the third negative value has been successfully sent in phase V, a line disconnection command is issued in phase (2), and the communication is terminated.

Next, a more detailed example of a transmission error signal processing method will be described based on FIGS. 1A and 1B.

As shown in Figure 1A, on the transmitting side, the pre-communication procedure and
Do training. This is Phase I in the table. Then, reset the number of retransmissions S, and put 1 in K to preset the number of transmission lines to 1 (
Step A). After this, read the original with reading bag W16,
The image signal is stored in the image signal RAM 12. The accumulation is repeated until the data for one page of the manuscript is stored in one block, and if the data overflows in the middle, it is stored in the second block, but before entering the second block, the process moves to step B, and the data for one page of the manuscript is stored without overflowing. When the storage for the next document is completed, the presence or absence of the next document is detected, and if there is, the process moves to step B as in the case where there is an overflow, and if there is no document, the process moves to step C.

In step B, all the memory contents are transmitted line by line starting from the line stored in one block of the image signal RAM 12, and at the end of the transmission of the first block, if there is one page of the original, the multi-page signal MPS is sent. If it is less than one page of the document, a divided page signal PPS is sent instead of MPS and the state is entered into a dawning state (step D). That is, regardless of the state of the receiving side, the entire memory contents of one block are sent and the signal from the receiving side is received.

On the other hand, as shown in FIG. 1B, on the receiving side, the same pre-communication procedures and training as on the transmitting side are performed, and after resetting the number of receiving lines in the receiver (step M),
The image signal sent from the transmitting side is received line by line (step N), and it is determined whether there is a reception error. If there is no error, the process moves to step O, and conversely, if there is an error, the process moves to step P.

In step 0, after adding 1 to the number of received lines and recording one line using the printer 5, it is determined whether or not the image signal has ended. If not, it is assumed that the transmission of one block has not yet been completed, and the process returns to step N to repeat the reception. However, if the image signal has been completed, the content of the transmission signal issued by the transmitting side at the time of completion is further determined, and the content is confirmed. If it is a divided page signal PPS or a multi-page signal MPS, after transmitting the message confirmation HMCF, the process returns to step M to receive the next block contents. In addition, if the content is the procedure end EOP, after similarly transmitting the MCF, upon receiving the line disconnection command DCN from the transmitting side, (
Step Q), disconnect the line and end the communication. In this way, when there is no error, the number of received lines is increased by 1 and recorded line by line.

In step P, which proceeded with an error, unlike the case without an error, the addition to the number of normally received lines up to that point and the recording of the one line in which the error occurred are reserved, and the judgment of the end of the direct image signal is made. conduct. Even if an error occurs in the middle of a block, the content of the transmission signal issued by the transmitting side is determined after waiting for the transmission of one block's worth of image signals to be completed.

If it is PPS or MPS, the process returns to step M after transmitting a transmission error signal PPP containing information for the number of lines that have already been successfully received within the block. If it is EOP, move to step Q. In this way, when an error occurs, recording is stopped after the line where the error occurred, and the number of received lines sent to the transmitting side is set to the number before the error occurred.

Thus, when there is no error, the receiver sends the message confirmation signal @MCF and the number of received lines up to that point, and when there is an error, the receiver sends the message confirmation signal @PPR and the number of lines where the error occurred.
The number of previous receiving lines is sent to the transmitter.

Returning to FIG. 1A again, in step D, upon receiving the signal from the receiving side, the content is determined,
Message sure! ! ! In the case of XMCF, return to step 8 as there is no transmission error, read the next page of the original or the remainder of one page of the original, and move on to the next block? Multiply M. If the transmission error signal is PPR, it is assumed that there is a transmission error and the process moves to step E. Here, it is determined whether the number of reception lines in the receiver is zero or not, and if it is not, the number of retransmissions S is reset, assuming that the communication failure is not the first line of the first block. K is added to the number of reception lines immediately before the error occurred, that is, since =1, K is set to the number of lines where the error occurred, and the process returns to step B. Further, if the number of reception lines is zero, it is assumed that communication has failed on line 1 of one block, and it is subsequently determined whether the number of retransmissions S when a transmission error occurs is 3 or not. If it is less than 3, add 1 to S and return to step B, but if it is 3, it is meaningless to repeat it any more and send a line disconnection command DCN.Step F), disconnect the line and communicate. end. In this way, each time the transmitting side transmits one block, it stops transmitting and has a signal from the receiving side, and if that signal is an error signal, the line of one block that was successfully received is Transmission is restarted from the line number plus 1, that is, from the line number where the error occurred. Further, if communication fails three times in a row on the first line of the first block, the line is disconnected.

Step C and subsequent steps are the flow for transmitting the final manuscript, and instead of transmitting PPS or MPS, a procedure end signal E is sent.
Except for issuing the OP, the flow is the same as that performed after step B described above, so the explanation thereof will be omitted.

In this way, according to the above embodiment, the transmission error signal PPR
Display of optional non-standard WINSF, NSS
By waiting for the completion of transmission of one block and determining the display contents, it is easy to prevent errors in transmitting image information during half-duplex communication.

This can be dealt with in a reliable manner.

In particular, the image signal RAM is divided into blocks for each page of the standard original 1i and stored each time, so there is no need for storage capacity for all pages of the original, and error handling is possible because retransmission is performed in blocks. Become quick.

[Efficacy of invention! ll! ] In other words, according to the present invention, the transmitting side stops transmitting every time it transmits one block and receives the signal from the receiving side, and when there is a transmission error, it receives the signal from the line of the block where the transmission error occurred. Since the transmission is re-transmitted, it is possible to deal with image information transmission errors in a simple and reliable way.Accurate image information can always be sent to the receiver, and because it is a half-duplex system, the equipment is inexpensive. It is.

[Brief explanation of drawings]

The first AIg is a transmitting side flowchart of a communication error processing method in a facsimile according to an embodiment of the present invention.
Similarly, Blffi is a receiving side 70-chart, and FIG. 2 is a block diagram of an example of a facsimile machine for implementing the method of the present invention. In the figure, 12 is a RAM for image signals.

Claims (1)

[Claims] At least an image signal memory is provided on the transmitting side, and after dividing the original into blocks and storing the image signals read from each block in the image signal memory each time, the stored image signals for one block are read line by line. The receiving side detects the presence or absence of a transmission error every time it receives one line image signal, records that one line if there is no transmission error, and stores the number of recorded normal lines, while transmitting. If there is an error, wait until the transmission of the block is completed and send the transmission error and the number of normal lines to the sending side, and then the sending side that receives these will add 1 to the number of normal lines of the block. A communication error processing method in facsimile, characterized in that the image signal is read out again from the number of lines and retransmitted.