JPS63287172A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To improve transmission efficiency and to prevent the duplicated transmission of a normal page to the reception side by re-transmismitting only an image-reception-errored page in a window size in case the image reception error occurs. CONSTITUTION:An original to be transmitted is read by a reader 1, a bit of image information is compressed by an encoder/decoder 4, and the image information is accumulated in a memory accumulator 5. Accordingly, under an instruction from a central processing unit 2, a line controller 6 transmits/receives various line control signals to the opposite facsimile terminal in accordance with a protocol. In the event of an error, an errored image is re-transmitted from the memory accumulator 5 as in the control of the protocol.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a facsimile device δ.

[Prior Art] A conventional 04 facsimile installation in accordance with CCITT's T.62 Recommendation (control procedures for Teletex and Group 4 facsimile services) uses a CDU as shown in Fig. 4.
Images are sent using I (command, document, user, information) signals.

Also, according to the concept of window size, it is possible to send pages of the window size WS (integer value) without waiting for a response from the other receiver (RDPBP, ie, response, document, page, boundary, positive).

An example of this is shown in FIG. 5, where WS=3.

Here, the window size WS is the number of pages that can be sent without waiting for a response from the other receiver. Note that FIG. 4 is a diagram showing the G4 communication protocol in the case of window size=1.

On the other hand, CCITT Recommendation T.62 stipulates that if an error is detected on the receiving side, a negative response of RDPBN (Response, Document, Page, Boundary, Negative) should be returned. In this case, the transmitting side can resume transmission using a predetermined method.

However, in the above conventional example, all of the pages marked with circles among the received page numbers shown in FIG. Duplicate output. Furthermore, since the first page is an error image, the received image of the first page is different from the received image of the first page output at the time of retransmission.

In the conventional apparatus, as shown in FIG. 5, for example, if only the first two pages have an error, the third page, which did not have an error, must also be retransmitted.

[Problems to be Solved by the Invention] If an error occurs on a certain page, the pages without the error must also be resent, resulting in the same document being sent twice, which causes confusion on the receiving side.

It has been reported that since normal pages are retransmitted, transmission efficiency decreases accordingly.

[Means for Solving the Problems] According to the present invention, when an image reception error occurs, only the image reception error page within the window size is retransmitted to the sending side.

[Effect] The present invention is applicable when an image reception error occurs.

Since only the image reception error pages within the window size are retransmitted to the transmitting side, confusion does not occur on the receiving side, and since normal pages are not retransmitted, it is possible to prevent a decrease in transmission efficiency.

[Example] FIG. 1 is a block diagram showing an embodiment of the present invention.

This embodiment includes a reading device t that reads an image when copying or transmitting, a central processing unit 2 that controls the entire device,
A recording device 3 that prints images when copying or receiving, an encoding/decoding device 4 that compresses or expands image information when sending and receiving facsimile images, a memory storage device 215 that temporarily stores images, and a facsimile A line control device 6 that sends and receives signals to the line used for communication
and has.

Further, the central processing unit 2 is an example of means for retransmitting only the image reception error page within the window size to the transmitting side when an image reception error occurs.

According to the CCITT T.62 recommendation, the page number is 1.2.
, 3.4, old..., etc., and must be sent in natural number order. By the way, the above embodiment uses CDCL (document machine list command)
/RDCLP (Document Device List Acknowledgment Response) uses the NSC (Non-Standard Terminal Section) to perform negotiation in advance to check whether or not the device has the functions of the above embodiment, and if it does have the functions. , the error retransmission method for mutual communication is performed as described above.

Next, the operation of the above embodiment will be explained.

FIG. 2 is a flowchart showing the operation of the above embodiment. Further, FIG. 3 is a diagram showing an example of a communication protocol for retransmitting only the second page when only the second page has an error in the above embodiment.

In the flowchart shown in FIG. 2, first, the reading device 1 reads a document to be transmitted (St), the encoding/decoding device 4 compresses image information (S2), and the memory storage device 215 compresses the image information. Accumulated (S3)
Thereafter, in response to instructions from the central processing unit 2!12, the line control device 6 transmits and receives various line control signals according to the protocol shown in FIG. 3 to and from the other party's facsimile terminal (S4).
, If an error occurs (S5), the error image is retransmitted from the memory storage device 5 (S6) as controlled by the protocol shown in FIG.

In this way, only error images are retransmitted, and there is no need to retransmit normal pages.
In addition to extremely high transmission efficiency, no duplicate normal pages are sent to the receiving side, and no confusion occurs on the receiving side.

[Effects of the Invention] According to the present invention, there is no confusion on the receiving side, and since normal pages are not retransmitted, it is possible to prevent transmission efficiency from becoming low.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention. FIG. 2 is a flowchart showing the operation of the above embodiment. FIG. 3 is a diagram showing the communication protocol in the above embodiment. FIG. 4 is a diagram showing a normal communication protocol with a window size WS;l. FIG. 5 is a diagram showing a conventional 64 communication protocol with a window size WS=3. 1... Reading device, 2... Central processing unit, 3... Recording device, 4... Encoding/decoding device, 5... Memory storage device, 6... Line control device. Patent Applicant Canon Co., Ltd. Agent Arata Yokubo - Figure 4 Figure 2 N1--Pi Figure 3 Ichishin Tari Mourning! <-S NO, Jtfi4(No, NG page NO
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Claims (1)

[Claims] A facsimile device characterized in that, when an image reception error occurs, only the image reception error page within a window size is retransmitted to a transmitting side.