JPH04176261A - Method for controlling transmission of facsimile equipment - Google Patents

Abstract

PURPOSE:To properly transmit image information in an error transmitting mode even when the dispersion of a MODEM is generated in the receiving side by setting up the transmitting time of image information for one block to a time shorter than a time required from the generation of the MODEM dispersion on the receiving side up to the termination of receiving operation on the receiving side. CONSTITUTION:When the transmitting time of image information may be extended from a prescribed time, the transmission of the image information is terminated at the prescribed time and a time-out signal is transmitted. The prescribed time is set up to a time slightly shorter than the sum of a time required from the MODEM dispersion state of a group-3 facsimile(G3 FAX) MODEM 9 up switching to its slow MODEM function and a time required from the switching to the slow MODEM function up to the termination of a receiving state. At the time of receiving image information cut out by the time-out, the receiving side connects the received image information with the succeeding image information to reconstitute image information for one page and records the reconstituted image as a received image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a transmission control method for a facsimile machine equipped with an error correction transmission mode.

[Prior Art] In general, Group 3 facsimile devices have data transmission speeds of 960°bps and 720°bps when transmitting image information.
Either a high-speed modem function of 0 bps, 4.800 bps, or 2400 bps is used. Here, 9600
bps, 7200bpS is CCI TT Recommendation v, 29
The data modem function specified in 48
00 bps.

For 2400 bps, the data modem function specified in CCI TT Recommendation V, 27ter is used.

These high-speed data modem functions require multiple phases of modem training (retraining) to synchronize phase timing with other modem functions or initialize scramblers, etc., before transmitting user data. is performing an action.

During this modem training operation, if impulse noise or the like is applied to the transmission line and the modem training operation of the data modem function on the receiving side does not end normally, causing so-called modem divergence, then (a
Since the data modem function on the receiving side cannot normally receive the received data, the receiving side terminates the receiving operation and moves on to preparation for receiving the next transmission procedure signal. Note that the transmission procedure signal is transmitted using the CCTTT Recommendation V, 21 modem function (hereinafter referred to as low-speed modem function) with a transmission speed of 300 bps, so it is not easily affected by line quality.

FIG. 7 shows an example of a transmission procedure of a group 3 facsimile device.

Transmitting side power) When the receiving side is called, the receiving side responds with a called station identification signal CED to notify that the own terminal is a non-voice terminal and a digital identification signal DIS to notify the transmission function of the own terminal. do.

The transmitting side sets the transmission function such as the modem speed to be used at that time based on the received digital identification signal DIS, and transmits the setting contents to the information field of the digital command signal DC8 to the receiving side. A training check signal TCF is sent out for training whether or not image information can be transmitted at the modem speed set at that time.

Based on the reception result of the training check signal TCP, the receiving side determines whether it is in a state where it can receive image information at the modem speed, and if it can receive image information, it responds with a reception preparation confirmation signal CFR. .

When the sending side receives the reception preparation confirmation signal CFR, it reads the original to be sent, forms an image signal, encodes and compresses the image signal using the encoding method set at that time, and outputs the resulting image. Send information PIX. At this time, if the original to be transmitted is one page, a procedure end signal EOP is transmitted following the image information PXx.

[Problems to be Solved by the Invention] As described above, the transmitting side performs a training operation according to the set modem speed immediately before starting to transmit the image information PIX.

If impulse noise occurs at time 1 during this training operation and the modem on the receiving side cannot perform the training operation normally, the receiving side will detect that a predetermined time Ta (for example, 6 seconds) has elapsed since time 1. At time t2, the high-speed modem function of the modem is terminated, and the modem is switched to a low-speed modem function in order to receive the transmission procedure signal.

In addition, if the receiving side cannot receive the transmission procedure signal after switching to the low-speed modem function until the predetermined time Tb (for example, 18 seconds) has elapsed, the receiving side ends the receiving operation at that time 3, and The line will be restored as soon as possible.

Here, if the image information PIX is longer than the time (Ta + Tb), the receiving side has finished the receiving operation and restored the line while the sending side was sending the image information PIX, so the image information PIX is longer than the time (Ta + Tb). In response to the subsequently transmitted procedure end signal EOP, the transmitter cannot receive a predetermined response signal from the receiving side within the specified time, so the transmitter sends the procedure end signal EOP.
After repeatedly transmitting 3 times, a disconnection command signal DCN is sent to restore the line. Further, in this case, a transmission error is determined on the transmitting side, and an appropriate display is performed.

As described above, conventionally, when the transmission time of the image information is long and the modem diverges on the receiving side, there has been a problem that the image information cannot be properly transmitted.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a transmission control method for a facsimile machine that can appropriately transmit image information even when modem divergence occurs on the receiving side. It is said that

[Means for Solving the Problems] According to the present invention, when the transmission time of framed image information reaches a predetermined time, the transmitting side ends the transmission of one block of image information at that point and stops transmitting the image information. A timeout command signal is sent to notify that the time has reached a predetermined time, and when the receiving side receives the timeout command signal,
The image information for one block received at that time is held, and when the reception of the remaining image information of the same page is completed, the image information is reconstructed as image information for one page.

[Operation] Therefore, it is possible to set the transmission time of one block of image information to be shorter than the time from when the modem diverges on the receiving side until the receiving side aborts the receiving operation. Even if modem divergence occurs, image information can be appropriately transmitted in error transmission mode.

[Embodiments] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a Group 3 facsimile machine according to one embodiment of the present invention.

In the figure, a control unit 1 performs control processing of each part of the facsimile machine and facsimile transmission control procedure processing, and a system memory 2 stores control processing programs and processing programs executed by the control unit 1. The parameter memory 3 is used to store various data required when executing the fax machine, and also constitutes the work area of the control unit 1. The parameter memory 3 is used to store various information specific to this group 3 facsimile machine. It is.

The scanner 4 is for reading original images at a predetermined resolution, the plotter 5 is for recording and outputting images at a predetermined resolution, and the operation display section 6 is for operating this facsimile device. It consists of various operation keys and various displays.

The encoding/decoding unit 7 encodes and compresses the image signal and decodes the encoded and compressed image information into the original image signal, and the image storage device 8 encodes and compresses the encoded and compressed image information. This is for storing a large amount of image information in a different state.

The group 3 facsimile modem 9 is for realizing the group 3 facsimile modem function, and has a low-speed modem function (V, 2) for exchanging transmission procedure signals.
1 modem) and a high-speed modem function (V, 29 modem, V, 27ter modem) mainly for exchanging image information.

The network control device 10 is for connecting this facsimile device to the public telephone line network, and has an automatic call originating and receiving function.

These control unit 1, system memory 2, parameter memory 3, scanner 4, plotter 5, operation display unit 6, encoding/decoding unit 7, image storage device 8, group 3 facsimile modem 9, and network control device 10 is connected to a system bus 11, and data exchange between these elements is mainly performed via this system bus 1.

Further, data exchange between the network control device 10 and the group 3 facsimile modem 9 is direct.

This embodiment has an error correction transmission mode (ECM) transmission function, and next, the error correction transmission mode will be explained.

In this error correction transmission mode, the image information after encoding and compression is 256 bytes (octets) from the beginning.

■Byte (-1 octet) = 8 bits) or 64
The frame size is divided into bytes, and the image information for one frame is divided into I-(DLC
(High Level Data Link Control) It is transmitted in a formatted frame FLM in the procedure format.

Here, this frame FLM includes a (head) flag sequence F1 consisting of a predetermined bit pattern, an address field A consisting of a predetermined bit pattern (global address), a control field C1 consisting of a bit pattern unique to the facsimile machine, an information field ■, Frame check sequence FC8 for error detection and (
(Tail) is formed by sequentially arranging flags F.

The information field I includes a facsimile control field FCF in which a facsimile transmission procedure signal is placed, and a facsimile information field PIF in which various information added to the facsimile transmission procedure signal is placed.

In this case, the facsimile control field FCF contains facsimile encoded data F of the facsimile transmission procedure signal.
The CD is placed, and the facsimile information field PIF contains a frame number FNo indicating the frame order,
Encoded frame data FDc of one frame size SZ is arranged.

Also, since the frame number FNo is an 8-bit binary number, it can only take consecutive numbers from 0 to 255, so 256 consecutive frames are set as one block, and the receiving side of that block requests retransmission. ing. Furthermore, if one page's worth of image information cannot be transmitted in one block, the remaining portion is set in the next block and transmitted.

When requesting retransmission, the receiving side sends a message as shown in (b) of the same figure.
A frame of a facsimile transmission procedure signal PPP (partial page request signal) is responded to the transmitting side.

Note that the facsimile transmission procedure signal is exchanged in the same frame format as the partial page request signal PPP, including necessary parameters, but in the following description, for example, 11 is replaced with the partial page request signal PPP. Describe it.

This partial page request signal PPP has a bit pattern (PPP) for generating the partial page request signal PPR arranged in its facsimile control field FCF, and 256-bit error map data EMp arranged in its facsimile information field FTF.

This error map data EMp assigns data rQJ to frames in which no transmission errors occurred, and data "1" to frames in which transmission errors occurred, out of one block of transmitted frame data. It is arranged in the same category.

Upon receiving this partial page request signal PPR, the transmitting side retransmits only the frame data of the frame in which data "1" is set in the error map data EMp to the receiving side.

By repeating this retransmission request until transmission errors in all frames are resolved, it is possible to record and output an error-free received image on the receiving side.

FIG. 3 shows an example of the procedure for image information transmission using this error correction transmission mode.

When the sender calls the receiver, the receiver responds with a called station identification signal C' ED and a digital identification signal 1) IS.

The transmitting side sets the transmission function such as the modem speed to be used at that time based on the received digital identification signal TS, and sends the setting contents to the information field of the CS as a digital command signal 1). Training check signal TCP for training whether image information can be transmitted at the modem speed set at that time.
Send out. At this time, it is declared to the receiving side that the error correction transmission mode will be used.

Based on the reception result of training check signal 1' CF, the receiving side determines whether it is in a state where image information can be received at the modem speed, and if image information can be received, it sends a reception preparation confirmation signal CFR. respond.

When the sending side receives the reception preparation confirmation signal CFR, the sending side reads the transmission original to form an image signal, and further encodes and compresses the image signal using the encoding method set at that time, thereby generating image information. f) Convert IX into the above-mentioned framed image information PI
Send X. At this time, if the amount of information of the image information PIX is smaller than the limit value for one block, the sending side
Following the image information PIX, procedure end signals PPS and EOP are transmitted.

The receiving side detects an error in each frame of the received image information PIX, and if it detects an error in one or more frames, it forms a double partial page request signal PPR and sends it to the transmitting side. do.

When the transmitting side receives the partial page request signal PPP, it compiles the image information of the error frame specified by the error map data EMp and transmits it as retransmission image information PIXc.

If the reception result of this retransmission image information PIXc is good, the receiving side responds with a message confirmation signal MCF, and upon receiving the message confirmation signal MCF, the transmitting side sends a disconnection command signal DCN to restore the line. do.

Upon receiving the disconnection command signal DCN from the transmitting side, the receiving side restores the line.

Now, between the group 3 facsimile machines of this embodiment,
When using the error correction transmission mode, the following operations are performed. Note that in this case, the original to be sent is two pages long.

That is, as shown in FIG. 4, when the transmitting side calls the receiving side, the receiving side responds with a called station identification signal CED and a digital identification signal DIS.

The transmitting side sets the transmission function such as the modem speed to be used at that time based on the received digital identification signal IS, sets the setting contents in the information field of the digital command signal DC8, and sends it to the receiving side. Then, a training check signal (CF) for training whether image information can be transmitted at the modem speed set at that time is transmitted. At this time, the receiving side is declared to use the error correction transmission mode.

The receiving side determines whether the image information can be received at the modem speed based on the reception result of the training check signal TCr-', and if the image information can be received, the reception preparation confirmation signal CFR is sent. respond.

When the sending side receives the reception preparation confirmation signal CFR, the sending side uses the scanner 4 to read the transmission document of 1 page 1'' to form an image signal, and then encodes and compresses the image signal using the encoding method set at that time. and the image information P obtained thereby
IXla is converted into the above-described framed image information, and the framed image information PIXla is transmitted.

At this time, the transmission time of the image information PIX1a is a predetermined time TA.
If it becomes longer than , the transmission of the image information P I Here, the time TA is the time from when the group 3 facsimile modem 9 enters the modem divergence state until it switches to the low-speed modem function, and the time from when the group 3 facsimile modem 9 switches to the low-speed modem function until it terminates the receiving state. The time is set slightly shorter than the total sum. For example, if these times are under the same conditions as the conventional device, the time TA is 20
Seconds are set.

The receiving side detects an error in each frame of the received image information PiX1a, and if no error is detected, it responds with a message confirmation signal MCF and holds the page of the image information PTX1a received at that time. keep it in that state.

When the sending side receives the message confirmation signal MCF, it reads the remaining images on the same page, converts them into framed image information PIX1b in the same way as the "lever" series, and sends them.
When the transmission is completed, multi-page signals PPS and MPS are sent out.

The receiving side detects an error in each frame of the received image information PIX1b, and if no error is detected, it responds with a message confirmation signal MCF and sends the received image information PIX1b.
The image information for one page is reconstructed based on the image information PIX1b and the image information PIX1b, and the plotter 5 starts recording the image of the image information.

When the sending side receives the message confirmation message (MCI), it reads the second page of the sending original using the scanner 4, forms an image signal, and sends the framed image information PIX2a in the same manner as described above. Form and send.

At this time, the transmission time of the image information PIX2a is a predetermined time TA.
If it becomes longer than , the transmission of the image information PIX2a is terminated at that point, and timeout signals To and PPS are transmitted to indicate that the transmission has ended due to timeout.

Here, the time when the transmission of the image information PIX2a was started is 5.
When impulse noise enters the transmission line and modem divergence occurs in the group 3 facsimile modem 9 on the receiving side, the signal energy of the high-speed modem function is no longer detected and at time 6 a predetermined period of time has elapsed. , switches to low-speed modem function.

Then, before the receiving side aborts the reception operation, the transmitting side sends timeout signals To and PPS, so the receiving side receives the timeout signals TO9PPS. Partial page request signal P I) requesting frame retransmission
R and responds to the sender.

As a result, on the sending side, the partial page request message sends the image information PIX2a again based on the contents of the PPP.

The receiving side detects an error in each frame of the received image information PIX2a, and if no error is detected, it responds with a message confirmation signal MCF and holds the page of the image information PIX2a received at that time. keep it in that state.

When the sending side receives the message confirmation signal MCF, it reads the remaining images on the same page, converts them into framed image information 1) r x 2 b, and sends them in the same way as in the series. In this case, since there is no subsequent page, procedure end signals PI)S and MPS are sent.

The receiving side detects an error in each frame of the received image information PIX2b, and if no error is detected, it responds with a message confirmation signal MCF and returns the received image information PIX2b.
2a and image information PTX2b, one page's worth of image information is reconstructed, and the operation of recording and outputting the image of the image information from block 5 is started.

When the transmitting side receives the message confirmation signal MCF, it sends out a disconnection command signal DCN to restore the line.

Upon receiving the disconnection command signal DCN from the transmitting side, the receiving side restores the line.

In this way, in this embodiment, when transmitting image information in the error correction transmission mode, since the transmission time of one image information block is specified not to exceed the predetermined time TA, Even if the modem modem 9 causes modem divergence, the receiving side can reliably receive the procedure signal transmitted following the image information block, and the image information transmission operation can be continued.

Furthermore, when the receiving side receives image information that has been cut off due to a timeout, it combines it with the subsequent image information to reconstruct one page's worth of image information, and records and outputs it as a received image.

FIG. 5 shows an example of transmission processing.

When a call is made to the designated destination (process 101), a pre-transmission procedure is executed with the other party's terminal (process 102), and settings such as transmission functions are made.

At this time, it is checked whether the error correction transmission mode has been set (decision 103), and if the result of determination 103 is No, the process shifts to normal procedure operation.

When the result of judgment 103 is YES, the ``Y'' timer is started (process 104), and the scanner 4 is activated to read the original image (process 105), and the image signal obtained thereby is encoded and decoded by the encoder/decoder 7. Processing for encoding and compression with 10
6) The image information thus obtained is converted into a frame and transferred to the group 3 facsimile modem 9.+07) The image information is transmitted.

Here, until the image information transmission for one page is completed or the TA timer times out, processing 104 to
Repeat the sending operation in step 107 (judgment 108.) 0
If the result of the judgment 109 is YES because the TA timer is a timeout signal, the timeout signal TO8PPS is sent as a command signal (processing 110), and a response signal from the receiving side is received (processing 111).

It is checked whether the response signal is the partial page request signal PPP (decision 112), and when the result of determination 112 is No, the process returns to process 105 in order to transmit the remaining image information of the same page.

Further, when the result of the judgment 112 is YES, the image information of the error frame specified by the error map data EMp of the partial page request signal PPP is compiled, and the image information of the error frame is transmitted.
Returning to process 110, timeout signals To and PPS are transmitted.

When the result of judgment 108 is YES, scanner 4
(Judgement 114), and when the result of determination 114 is YES, multi-page signals PPS and MP are sent as command signals.
S is sent (process 115), and a response signal is received from the receiving side (process 116).

It is checked whether the response signal is the partial page request signal P P P (decision 11.7), and whether the result of decision 117 is N
When it becomes O, the process returns to process 10/l in order to transmit the image information of the next page.

Furthermore, when the result of judgment 117 is y r = s, the partial page request signal I) l) compiles the image information of the error frame specified by the error map data EMp of R, and transmits the image information of the error frame. After processing 11.8), the process returns to step 115 and transmits the multi-page signals PPS and MPS.

When the result of judgment 114 is NO, process 119) to send out procedure end signals PPS and EOP as command signals.
, receives a response signal from the receiving side (processing) 20).

It is checked whether the response signal is the partial page request signal PPP (decision 12], ), and when the result of determination +21 is No, the line is restored and the transmission operation is ended (process 122).

In addition, when the result of judgment 121 becomes YES, EM overnight
Process 123 to collect the image information of the error frame specified by p and transmit the image information of the error frame.
), returns to process 119 and receives procedure end signals PPS, EOP.
Send.

FIG. 6 shows an example of reception processing.

When an incoming call is detected, a pre-transmission procedure is performed with the other party's terminal to set the transmission function, etc. (processing 201).

At this time, it is checked whether the error correction transmission mode is set (determination 202), and if the result of determination 202 is No, the process shifts to the normal procedure.

When the result of determination 202 is YES, one block of image information is received (process 203), and a command signal is received (process 204).

Then, it is checked whether the received image information includes an error frame (decision 205), and when the result of determination 205 is YES, an error map 9A-data EMp is formed that collects the detected error frame; The error map data EMp
Partial page request signal PI) I-? (Process 206), and the process moves to Process 203.

When the result of the decision 205 is No, the message confirmation signal MCF is responsively processed 207), and it is checked whether the received command signal is the procedure end signal I) PS, EOP (decision 208).

When the result of the judgment 208 is YES, the plotter 5 starts recording and outputting the image of one page of image information that has been received at that time (process 209), and restores the line (process 2] 0). , ends the reception operation.

When the result of judgment 208 is NO, it is checked whether the received command signal is a timeout signal TO, PPS (judgment 211), and when the result of judgment 211 is YES, the image information received at that time is checked. With the page held on hold without performing any recording operation (process 212), the process moves to process 203 to receive subsequent image information.

When the result of the judgment 211 is No, this means that the multi-page signals PPS and MPS have been received as command signals, so the plotter 5 does not start recording and outputting the image of one page of image information that has been received at that time. Processing 21
3) The process moves to process 203 to receive the image information of the next page.

By the way, in the embodiment described above, the transmission time of one image information block is limited to 20 seconds, but this setting time is not limited to this, and if modem divergence occurs with the high-speed modem function, Any time can be set as long as the time can receive the procedure signal to be transmitted following the image information block while the low-speed modem function is switched.

In addition, in the two examples, a non-standard transmission procedure signal called a timeout signal was used, but instead of this signal,
PPS is a standard transmission procedure signal.

Nu]] can be used.

[Effects of the Invention] As explained above, according to the present invention, ■ the time for transmitting image information for 9 minutes for the blower is longer than the time from when the modem diverges on the receiving side to when the receiving side aborts the receiving operation; Therefore, even if modem divergence occurs on the receiving side, image information can be appropriately transmitted in the error transmission mode.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a Group 3 facsimile device according to an embodiment of the present invention, FIG. 2(a) is a schematic diagram showing an example of framed image information, and FIG. 2(b) is a partial page request signal. Figure 3 is a schematic diagram illustrating the signal format of the error correction transmission mode.
FIG. 4 is a time chart showing an example of a transmission procedure according to an embodiment of the present invention, FIG. 5 is a flowchart showing an example of a transmission process, and FIG. 6 is a flowchart 1 to 7 showing an example of a reception process. The figure is a time chart for explaining the conventional problem.・

Claims (1)

[Claims] In a transmission control method for a facsimile machine equipped with an error correction transmission mode, when the transmission time of framed image information reaches a predetermined time, the transmission side ends the transmission of one block of image information at that point, and A timeout command signal indicating that the information transmission time has reached a predetermined time is sent out, and when the receiving side receives the timeout command signal, it retains the image information for one block received at that time and stores the remaining image information on the same page. When the image information has been received,
A transmission control method for a facsimile machine, characterized in that the image information is reconstructed as image information for one page.