JPH01220572A - Facsimile equipment - Google Patents

Abstract

PURPOSE:To perform fast data transfer by controlling communication speed based on the presence/absence of an error on a line. CONSTITUTION:When a re-transmission request signal PPR is issued from a reception side, a re-transmission request decision part 6b counts the number of times of issuing, and when it arrives a prescribed count value, it informs the face to a modem speed change processing part 6c. The processing part 6c issues instruction to perform a fall back processing to a protocol processing part 6d by the signal so as to lower the rank of transfer speed by one, and the processing part 6d lowers the transfer speed of data read out of a memory 6a, and informs the face to a modem 5. When a reception completion signal MCF is received, the decision part 6b informs the satisfactory state of a line to the processing part 6c, and the processing part 6c, when judging the fall back processing being performed, issues the instruction to step up modem speed to the processing part 6d, and the processing part 6d reads out data from the memory 6a at original transmission speed, and transmits it to the modem 5. In such a way, it is possible to perform fast data transfer.

Description

[Detailed Description of the Invention] [Summary] To enable a facsimile device having a G3 error correction function to step up the previous communication speed and switch to a faster communication speed when the line condition improves. It has a reading section that reads the information on the original, a recording section that outputs the received information, a main control section that performs various controls for transmission and reception, a modulation process for the data output to the line, and a processing unit that processes the data received from the line. A facsimile machine is equipped with a modem that tall processes transmitted data, and has an error correction function in G3 mode. The system is configured by providing a transmission control unit that has a fallback function to reduce the communication speed when a line error occurs, and a function to step up the communication speed when the line error disappears.

[Industrial Field of Application] The present invention relates to a facsimile machine having a G3 error correction function.

The facsimile machine 2 having the 03 function is currently out of use in all fields. In conventional devices of this type, when transmitting document information in the G3 mode, the state of the receiving side is not taken into consideration, and the transmission is performed in a so-called "flow-through" manner. Therefore, the status of the line carrying the information was not checked. For example, if intermediate data is transferred in a line error state, the receiving device receives the intermediate data in an unreliable state.

Even in such cases, it was unclear whether accurate information was received on the receiving side. In order to eliminate such defects,
In recent years, facsimile machines have been developed that correct errors by adding an error correction mode (abbreviated as G3ECM), which has not been considered in the conventional G3 mode.

[Prior art] The conventional G3 error correction mode uses unit data (
For example, errors are detected on a block-by-block basis, and if errors occur frequently, modem speed fallback is performed and data is retransmitted.

FIG. 5 is a diagram showing an example of the structure of data to be transferred.

In the example shown in the figure, one page shows data of 128 KB (B means byte), and is composed of a #1 block and a #2 block.

The capacity of each block is 64KB. Each block has 25
It consists of 6 frames, and each frame has a capacity of 256B. Note that here, fallback refers to processing that reduces the data transfer speed. The data transfer speed of the line is 9600 BOS, 7200 bps, 4
There is 800bpsW.

The G3 mode includes a training mode for checking the data transfer speed at which document information can be sent before sending it. Data is transferred from the sending side to the receiving side in units of 70 pieces at the transfer rate determined in this mode. Then, a reception response is returned from the receiving side. At this time,
2 signals indicating whether data was received correctly for each frame
Since the data is contained in a 32-byte data string corresponding to 56 frames, the sending side knows that there is an abnormality in the frame data, and if the abnormality is repeated a specified number of times, the data transfer speed is lowered than before and retransmitted.

In other words, do a fallback.

[Problem to be solved by the invention] In the conventional G3 error correction mode, if the transfer speed is reduced by falling back to -day, communication continues at the fallback modem speed even if the line becomes clear afterwards. are doing.

Therefore, there was a problem that the communication time became long.

The present invention was made in order to solve the above problem, and the present invention quickly responds to the line condition, and when the line condition improves, it steps up the previous communication speed to a faster communication speed. It is an object of the present invention to provide a facsimile device which can be switched to perform high-speed data transfer.

[Means for Solving the Problems] FIG. 1 is a block diagram of the principle of the present invention. The device shown in the figure is a facsimile device having an error correction function in G3 mode. In the figure, 1 is a reading unit that reads the information on the original 2, 3 is a recording unit that outputs the received information, 4 is a main unit that performs various 11J111 operations, and 5 is a modulation process for data output to the line, and a line This is a modem that processes data received from the . 6 has a memory 6a for temporarily storing transmitted data or received data, and has a fallback function that reduces the communication speed when errors occur frequently on the line, and a fallback function that reduces the communication speed when there are no errors on the line. This is a transmission control unit that has a step-up function.

[Operation] The transmission control unit 6 issues a fallback command to the modem 5 when it learns of a line abnormality during training, or when a retransmission request from the receiving device side occurs more than a predetermined number of times. Then, if it is determined that the line condition has improved during data transfer at a low communication speed due to fallback, the data transfer speed is stepped up again. By providing such a communication speed step-up function, it is possible to perform high-speed data transfer that quickly corresponds to line conditions.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a diagram showing a specific configuration example of the transmission i, 1jt1 section 6 viewed from the transmitting side. Components that are the same as those in FIG. 1 are designated by the same reference numerals. In the figure, 6b is a reception end signal MCF sent from the receiving side or a retransmission request signal PP.
A retransmission request determination section that receives R and determines whether there is a retransmission request; 6C is a modem speed change processing section that changes the modem speed according to the output of the retransmission request determination section 6b; 6d;
is the output of the modem speed change processing section 6C and the memory 6a.
This is a protocol processing unit that receives data stored in the data storage system and determines the procedure for transmission. The output of the protocol processing section 6d is input to the modem 5 (see FIG. 1). The operation of the circuit configured as described above will be explained as follows.

The retransmission request determination al16b constantly monitors whether there is a retransmission request from the receiving side. If a retransmission request signal PPP is received from the receiving side, the number of times the retransmission request signal PPP is received is counted, and when the specified count value is reached, the modem speed change processing section 6C is notified of the fact. When the modem speed change geography section 6C receives this signal, it changes the previous transfer speed by 1.
Lower the rank (for example, the previous 9600 bps)
(to lower the speed to 7200 bps) protocol processing unit 6
d (fall pack processing). The protocol processing unit 6d lowers the transfer speed of the data read from the memory 6a and transmits the reduced data to the modem 5.

On the other hand, if the response from the receiving side is not the retransmission request signal PPR but the reception completion signal MCF, the retransmission request determination unit 6b notifies the modem speed change processing unit 6C that the line condition is good. do. At this time, the modem speed change processing unit 6C determines whether fallback has occurred, and if so, instructs the protocol processing-6d to restore (step up) the modem speed. As a result, the protocol processing unit 6d reads the data from the memory 6a at the original transfer rate and transmits it to the modem 5.

FIG. 3 is a flowchart showing the operation of the facsimile machine on the sending side. First, the main INID unit 4 (see FIG. 1) performs phase B processing (step 1). Here, the phase 8 process refers to determining the transmission speed (baud rate), document size (for example, 84.A3, etc.), compression mode, etc.

Once the transfer mode is determined in step 1, the image data temporarily stored in the memory 6a is sent out (step 2). Next, the main 113111I unit 4 determines whether or not the block data transmission has been completed (step 3), and if it has been completed, it checks whether the page transmission has been completed (step 3).
Step 5).

If the transmission of the block data has not been completed, the process returns to step 2 and the transmission of the image data in units of blocks is repeated. When the page transmission is completed and there is no u%, an inter-block command PPS is transmitted to the line via the modem 5 (step 4). If it has been completed, then it is determined whether data transmission for all pages has been completed (step 6).

If it has been completed, send a transmission end command to the line (step 7) and receive a response from the receiving side.
1-) (Step 8), disconnect the line (Step 8)
,finish.

On the other hand, if data transmission for all pages has not been completed, the page data has been completed, and an inter-page command is transmitted to the line (step 10). In this state, it is checked whether a retransmission request response is received from the receiving side (step 11). If the retransmission request response is not received lI), it is the reception end signal MCF, so it is determined whether the data transfer rate at that time has fallen back (step 12), and if so, the retransmission request determination unit 6b (see FIG. 2) sends a step-up instruction command CTC to the modem speed change processing section 6C (step 13).

After sending the CTC command, once a response signal CTR is received from the receiving side (step 14)
, the main control unit 4 sets the data of the next page or block in the memory 6a (step 15). The same applies when fallback is not performed in step 12.

If, in step 11, the retransmission request response PPR
If the number of received PPR responses has reached the specified number (step 16), if it is less than the specified number, set a retransmitted frame (step 17), and return to step 2 to transmit the relevant frame data. will be retransmitted. Note that the PPP response signal is returned with the number of the frame data that was received incorrectly on the receiving side, so when retransmitting on the sending side, only the frame data that was incorrectly received can be read from the memory 6a and retransmitted. It looks like this. When the number of PPR receptions reaches a specified value, the retransmission request determination section 6b sends a fallback instruction command CTC to the modem speed change processing section 6C (step 18), which is sent to the receiving side via the line.

When the receiver receives the response CTR from the receiving side for this fallback command (step 19), the memory 6
The frame data to be retransmitted is read from a and set (step 17), and the frame data is sent from the protocol processing section 6d at the reduced transfer speed.

FIG. 4 is an explanatory diagram of the communication procedure of the embodiment. This shows the exchange of signals between the sending side and the receiving side. First, a call is made from the sending side to the receiving side.

When the receiving side detects a calling signal, it returns a signal CED indicating that the receiving side is a facsimile machine to the sending side, and then determines what kind of functions the facsimile machine has (for example, what size documents it can receive). etc. functions)
Returns a signal DiS indicating.

After confirming the function of the receiving side from the DIS signal, the transmitting side returns a signal DO8 to the receiving side indicating in what mode to transmit. After that, dummy data (9600 bps), which is the fastest baud rate (transfer speed), is sent from the sending side.
For example, a continuous signal of 1) is sent to the receiving side as a test signal TCP. Here, if the receiving side can receive data at that baud rate, a signal CFR indicating that data can be received is transmitted.
is returned to the sending side (if it is not received, a signal FTT to that effect will be returned). Upon receiving the CFR signal, the transmitting side sends the first block of image data to the receiving side at a baud rate of 9600bE)S. At the end of block data, a signal PPS indicating the end of the block and a signal NUL indicating that more block data will follow.
L is sent from the sending side to the receiving side.

In this case, if the line condition is poor and the receiving side is unable to receive all the frames in the block, then
A retransmission request signal PPR is returned from the receiving side to the transmitting side. When the transmitting side recognizes the problematic frame from the PPR signal, it reads only the relevant frame from the memory 6a and retransmits the image data to the receiving side, and then sends a signal PP5-N indicating the end of retransmission.
Sends ULL to the receiving side. Here, if data reception is not successful again due to poor line conditions, the PPR signal is sent from the receiving side to the transmitting side again.

Assuming that while repeating such a sequence, the number of PPR responses received by the transmitting side reaches a specified value, a fallback instruction command CTC is sent from the transmitting side to the receiving side.

On the receiving side, when receiving the CTC command, the speed is 9600 bps.
A message @CTR indicating that reception is possible at a speed lower than 7200bDS is returned to the sending side.

On the transmitting side, image data of the re-fermentation problem frame is transmitted at 7200 bps. When the receiving side receives the image data at this baud rate, it returns a reception end signal @MCF to the transmitting side.

On the sending side, the image data of the next second block is sent to 7200b.
It is transmitted at a rate of ps. When all the frame data of the block is received normally, the receiving side sends a reception end signal (
OK response) Returns the MCF to the sending side. When the sending side receives the τMCF response as the first response after the fall pack, it sends a step-up command CTC to the receiving side.
return it.

Stepped-up transfer rate of 960Qbp on the receiving side
Sends a signal CTR to the transmitting side indicating that it is possible to receive even s. On the transmitting side, upon receiving this CTR, it again transmits the next block of image data at a baud rate of 9600 bps, which is the highest transfer rate.

In the above explanation, a fallback is performed when the number of PPR responses reaches a specified value, but in the case of a model that has a training function such as G3 mode, a fallback is performed during training. Good too.

[Effects of the Invention] As explained above in detail, according to the present invention, when the line condition improves, the current communication speed is stepped up and the communication speed is increased. Since the communication speed can be switched to a higher communication speed, it is possible to provide a facsimile apparatus that can perform high-speed data transfer.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the principle of the present invention, Fig. 2 is a diagram showing a specific example of the configuration of the transmission control section, Fig. 3 is a flowchart showing the operation on the transmitting side, and Fig. 45! I is a detailed explanatory diagram of the present invention, and FIG. 5 is a diagram showing an example of a data configuration. In FIG. 1, 1 is a reading section, 2 is a document, 3 is a recording section, 4 is a main II 111 part, 5 is a modem, 6 is a transmission 11JII 1 part, and 6a is a memory. Patent applicant: Fujitsu Limited
? i ≧, y) Figure 5 of the old cylinder showing an example of the configuration of the Lukuso data.

Claims (1)

[Claims] A reading section (1) that reads information on a document (2), a recording section (3) that outputs received information, and a main control section (4) that performs various controls for transmission and reception. , A facsimile machine that has a modem (5) that modulates data output to the line and demodulates data received from the line, and has an error correction function in G3 mode. It has a memory (6a) for temporarily storing data, and has a fallback function to reduce the communication speed when a line error occurs, and a function to step up the communication speed when the line error disappears. A facsimile device comprising a transmission control section (6).