JPH0773325B2 - Facsimile communication method - Google Patents

Description

The present invention relates to a facsimile communication method that defines a communication control procedure between image communication apparatuses that exchange a plurality of pieces of image information.

[Conventional technology]

Here, the communication control procedure in the conventional facsimile apparatus will be described.

FIG. 2 shows an example of G3 transmission procedure based on CCITT recommendation T30. In this figure, 1 is an initial identification signal, 2 is a reception command signal, 3 is a TCF signal for checking whether transmission at this speed is possible, 4 is a reception preparation confirmation signal, 5 is a message signal, and 6 is a message. A post-instruction signal, 7 is a message confirmation signal, and 8 is a disconnection instruction signal. here,
When the post-message command signal 6 is the procedure end signal (EOP), the procedure goes to the step (a), and when it is the multi-page signal (MPS), the procedure goes to the step (b), and the message end signal ( If it is EOM), proceed to the procedure shown in (C).

[Problems to be solved by the invention]

According to the above procedure, the training signal is transmitted every time one page is transmitted. This training signal is as shown by reference numerals 3 and 5 when there is a mode change, that is, when the EOM signal is transmitted.
It will be sent twice.

As described above, the conventional method has a drawback that the training signal is transmitted every time one original is transmitted, and the procedure time is lengthened.

Further, when transmitting a plurality of originals without mode change, a training signal is transmitted before the message, and this training signal has the same transmission speed as the training signal transmitted one time before. . Therefore,
Since the message signal is transmitted after the training signal is transmitted one time before, there is a time lag until the next training signal is transmitted, and as a result, the line situation may be different.

As described above, the conventional method has a drawback that the procedure is less stable.

[Object] In view of the above points, an object of the present invention is to provide a facsimile communication method that shortens the procedure time and stabilizes the procedure.

[Means for solving problems]

The facsimile communication method according to the present invention is based on CCITT Recommendation G3.
In the facsimile communication method using the procedure signal of
On the transmitting side, it is necessary to send the image data of the next page after the RTC signal indicating the end of the image data of the first page by NSS.
After notifying the receiving side with a signal, the image data transmission is started, after the transmission of the image data of one page is completed, the RTC signal is transmitted, and the image data of the next page is transmitted following the RTC signal. , When the NSS signal notifies the sender that the image data of the next page is to be transmitted after the RTC signal, after receiving the image data of one page, the signal to be continuously received after the RTC signal is transmitted to the image of the next page. It is received as a signal.

〔Example〕

First, an outline of an embodiment of a facsimile apparatus to which the present invention is applied will be described.

On the receiver side, the non-standard function initial identification signal (NSF
Signal) or non-standard function transmission command signal (NSC signal)
Whether or not it has a function of executing the procedure method according to the present invention (that is, the procedure method of transmitting a plurality of pieces of information without transmitting a message confirmation signal from the receiver for each page). Notify the transmitter side.

This is, for example, the FIF in NSF or NSC signals.
Specific bits of (Facsimile information field) (eg
This is done by allocating the 51st bit). If the 51st bit of FIF in the NSF signal or the NSC signal is "0", it means that it does not have the function of performing the procedure by the procedure method according to the present invention. Further, if the 51st bit of the FIF in the NSF signal or NSC signal is "1", it has the function of performing the procedure by the procedure method according to the present invention.

On the transmitter side, when the receiver does not have the function of performing the procedure according to the present invention, the facsimile transmission is performed according to the procedure based on CCITT Recommendation T30. in this case,
The 51st bit of FIF in the NSS signal is "0". On the other hand, when the receiver has the function of performing the procedure according to the present invention, the procedure is performed according to the procedure according to the present invention. In this case, the 51st bit of the FIF in the NSS signal is set to "1" and the receiver is declared to perform the procedure according to the procedure method according to the present invention.

FIG. 1 shows an embodiment of the procedure system according to the present invention.

In FIG. 1, 9 is an initial identification signal, 10 is a reception command signal, 11 is a training signal, 12 is a message signal, 13 is a procedure end signal, 14 is a message confirmation signal, and 15 is a disconnection command signal. Here, when transmitting a plurality of sheets, the process proceeds to the beginning of the message signal 12 again after the transmission of the message signal 12 is completed, and the EOP signal is transmitted when the transmission of the final document is completed. As the mode state when transmitting multiple sheets,
It is possible to select either standard mode or fine mode, which communicates to the receiver with a special signal sent during the sending of the message signal.

In the procedural system according to this embodiment, the message signal 12
Must be in a retransmittable format. The receiver sends a NACK signal to interrupt the message transmission from the transmitter side when training reception fails or when a missing image signal occurs. After that, the receiver specifies the retransmission start line, the transmission speed, and the like, and the transmitter retransmits from the specified line at the specified speed.

Next, the message encoding method will be described with reference to FIG. In FIG. 3, (a) and (d) are line end signals (EOL). Following these (a) and (d), special signals as shown in (a) and (e) are transmitted. After that, as shown in (c), an image signal (for example, MH encoding is performed) is transmitted.

A specific example of the above-mentioned special signal is shown in FIG. In FIG. 4, the information on the left side is transmitted first. This signal is
A signal that can be distinguished from the EOL signal, for example, a 16-bit signal is used. Here, the bit indicated by (h) is a signal indicating a mode. That is, if the bit of (h) is "0", it means that the mode is standard mode, and if the bit is "1", it means that the mode is fine. In addition, the bit of (ke) and (ko) is set to "1" because EOL
This is because it can be distinguished from the signal. Furthermore, 13 bits indicated by * represent a line number.

When transmitting a plurality of originals, for example, six EOL signals are continuously transmitted as an end signal for one page. In the case of the final document, 20 EOL signals are continuously transmitted as an end signal for one page, for example. After that, the procedure signal is transmitted by the signal of 300b / s. Telephone reservations from the transmitter side can also be made by transmitting the PRI-EOP signal after transmitting the final document.

On the other hand, the receiver can identify whether or not it is the end signal of the page which is the final document by counting the number of continuous EOL signals. The telephone reservation from the receiver side for the final manuscript can be made by sending the PIP / PIN signal in response to the EOP signal. Also, for telephone reservations from the receiver side that occur during transmission of multiple originals, the NACK signal is sent after detecting the end signal of one page with the next original, and then the PIP / PIN signal is sent. It is possible to do so.

FIG. 5 is a block diagram showing an example of the transmitter side in the facsimile apparatus to which the present invention is applied.

In FIG. 5, reference numeral 20 holds a loop such that the telephone network is connected to the terminal of the line to control the connection of the telephone switching network and the data communication path is switched to use it for data communication. Network control unit (NCU)
Is. The signal line 20a is a telephone line. The NCU 20 inputs the signal of the signal line 44a, and if the signal level is "0", connects the telephone line to the telephone side (that is, the signal line 20a to the signal line 20b side). Further, the NCU 20 inputs the signal of the signal line 44a, and if the signal level is "1", the telephone line is connected to the facsimile machine side (that is, the signal line 20a side to the signal line 20c side). Under normal conditions, the telephone line is
It is connected to the telephone side.

22 is a telephone.

Reference numeral 24 is a hybrid circuit that separates a transmission system signal and a reception system signal. That is, the transmission signal of the signal line 36a is sent to the telephone line via the signal line 20c and the NCU 20. Further, the signal sent from the other party is output to the signal line 24a via the NCU 20 and the signal line 20c.

A reading circuit 26 sequentially reads an image signal for one line in the main scanning direction from a transmission document and creates a signal string representing binary values of white and black. This reading circuit 26 is a CCD (charge coupled device).
And the like, and an optical system. And
The binarized signal string representing white and black is output to the signal line 26a.

Reference numeral 28 is a circuit for inputting the binarized data output to the signal line 26a and encoding the data. This encoding circuit 28
Has a memory required for retransmission. And
When the signal level of the signal line 44d is "0", encoding is performed based on CCITT recommendation T4. On the other hand, when the signal line 44d is at the signal level "1", retransmittable coding is performed. Here, the signal of the signal line 44g is inputted, and when it is at the signal level "0", it is judged to be the standard mode. When the signal level is "1", it is determined that the fine mode is set. This judgment is made at the time of encoding.

When the procedure is performed by the procedure method according to the present invention, retransmittable coding is performed. The retransmittable coding is as described above. Then, in this case, the following control is performed.

When the signal level of the signal line 44b becomes "1", the image transmission is interrupted. Then, when the signal level of the signal line 44b becomes "0", the retransmission start line output to the signal line 44c is input and the retransmission is performed from this line. Encoding [MH
The data that has been (modified Huffman) coded, MR (modified read) coded, or coded for retransmission] is output to the signal line 28a.

Reference numeral 30 is a modulator that performs modulation based on the well-known CCITT recommendation V27ter (differential phase modulation) or V29 (quadrature modulation). The modulator 30 receives the signal on the signal line 28a, modulates the signal, and outputs the modulated data to the signal line 30a.

Reference numeral 32 is a modulator that performs modulation based on the well-known CCITT recommendation V21. The modulator 32 receives the procedure signal on the signal line 44f, modulates the procedure signal, and outputs the modulated data to the signal line 32a.

Reference numeral 34 is a circuit for generating an echo suppressor function stop tone on the signal line 34a when a pulse is generated on the signal line 44e. In particular, when performing full-duplex operation on an international line, it is necessary to send an echo suppressor disabling tone. In this embodiment, a 2100 Hz signal is continued for one second as an echo suppressor function stop tone. This circuit 34 generates a pulse on the signal line 34b when the transmission of the echo suppressor function stop tone is completed.

Reference numeral 36 is an adder circuit that inputs signals from the signal line 30a, the signal line 32a, and the signal line 34a, and outputs the addition result to the signal line 36a.

A demodulator 37 performs demodulation based on the well-known CCITT recommendation V21. This demodulator 37 inputs the signal on the signal line 24a and outputs V
21 demodulates and outputs the demodulated data to the signal line 37a.

38 is a signal line 38 when the signal of the signal line 24a is inputted and the NACK signal transmitted from the facsimile machine on the other side is detected.
This is a circuit that generates a pulse at a.

Reference numeral 39 is a circuit that detects the retransmission start line number that is transmitted subsequently to the NACK signal and outputs the line number to the signal line 39a.

Reference numeral 40 is a circuit for detecting whether or not a document is set on the platen. When the original is set on the platen, the signal of the signal level "1" is output to the signal line 40a,
On the other hand, if no document is set on the platen, the signal line
A signal of signal level "0" is output to 40a.

Reference numeral 41 is a mode selection detection circuit that detects whether the standard mode is selected or the fine mode is selected. When the standard mode is selected, a signal of signal level "0" is output to the signal line 41a, while when the fine mode is selected, the signal line 41a is output.
A signal of signal level "1" is output to a.

Reference numeral 42 is a circuit for detecting whether or not a telephone reservation is made. When the telephone reservation is made, the signal of the signal level "1" is outputted to the signal line 42a, while when the telephone reservation is not made, the signal level "0" is outputted to the signal line 42a.
Signal is output.

Reference numeral 43 is a circuit for calling an operator when a pulse occurs in the signal line 44h.

Reference numeral 44 is a control circuit that performs the control described below.

First, when the initial identification signal or the transmission command signal transmitted from the facsimile machine on the other side is detected, whether the 51st bit of the FIF in the NSC signal or the NSF signal representing the non-standard function is "1" (that is, Whether or not it has the function of performing a procedure in the procedure method according to the present invention).

When the receiver does not have the function of performing the procedure according to the procedure method according to the present invention (that is, when the 51st bit of FIF in the NSF signal or the NSC signal is “0”), the CCI is used.
Facsimile transmission is performed according to the procedure based on TT Recommendation T30. In this case, the 51st bit of FIF in the NSS signal is set to "0".

When the receiver has the function of performing the procedure according to the procedure method according to the present invention (that is, when the 51st bit of FIF in the NSF signal or the NSC signal is “1”), the transmitter is After detecting the initial identification signal (NSF / CSI / DIS) or transmission command signal (NSC / CIG / DTC), receive command signal (NSS
/ TSI / DCS: However, the 51st bit of FIF in the NSS signal is “1”), and then the training signal and the message signal are transmitted.

Standard / fine mode information is included in the message signal.

When transmitting a plurality of sheets, the EOL signal is sent out 6 times and then the message signal is sent out immediately. That is, the training signal is not transmitted.

When sending the final manuscript, as the end signal for one page
Transmits 20 EOL signals continuously. Subsequent steps are CCI
As shown in TT Recommendation T30. Therefore, it is possible to make a telephone reservation or the like. Also, the transmitter follows the NACK signal
When the PIP / PIN signal is detected, it is determined that the receiver has made a telephone reservation.

FIG. 6 is a flow chart showing a control procedure to be executed by the control circuit 44 shown in FIG.

In FIG. 6, a step S50 connects the telephone line to the telephone side. That is, the signal level of the signal line 44a is "0".
The signal of is output.

In step S52, it is determined whether transmission is selected. When transmission is selected, the process proceeds to step S54.

In step S54, the telephone line is connected to the facsimile machine side. That is, the signal of the signal level "1" is output to the signal line 44a.

In step S56, the procedure signal output to the signal line 37a is input, and the NSF / CSI / DIS signal or NSC / CIG / DTC signal is input.
It is determined whether the signal is received within 35 seconds. If the NSF / CSI / DIS signal or the NSC / CIG / DTC signal is received within 35 seconds, the process proceeds to step S58. On the other hand, after 35 seconds, NSF
If the / CSI / DIS signal or the NSC / CIG / DTC signal cannot be received, the process proceeds to step S50.

In step S58, it is determined whether or not the 51st bit of the FIF in the NSF signal or NSC signal is "1", that is, whether or not it has a function of performing the procedure according to the present invention. It When the 51st bit of FIF in the NSF signal or NSC signal is "1" (that is, when the receiver has the function of performing the procedure according to the procedure method according to the present invention), the process proceeds to step S60. On the other hand, when the 51st bit of FIF in the NSF signal or the NSC signal is "0" or when the NSF signal or the NSC signal is not detected (that is, the receiver performs the procedure according to the procedure method according to the present invention). If not), the process proceeds to step S70.

In step S60, the NSS (FIF
The 51st bit sends "1") / TSI / DCS signal.

In step S62, the training signal is transmitted.

In step S64, the message signal is transmitted. Here, transmission is performed in the retransmission mode. This encoding can specify standard / fine mode, as described above. When the PIP / PIN signal is detected after the NACK signal, the operator calling circuit 43 calls the operator. Further, when a message is transmitted using the international line, the echo suppressor function stop tone is always transmitted by the circuit 34 immediately before the image signal is transmitted.

Conditions for requesting retransmission from the receiver side (ie NA
Conditions for sending the CK signal) are set, for example, when training reception is unsuccessful and when continuous image errors of a certain number of lines or more occur.

The transmitter outputs a signal having a signal level "0" to the signal line 44b and a signal having a signal level "1" to the signal line 44d to perform message transmission in the retransmission mode. In the standard mode, the signal of signal level "0" is output to the signal line 44g, and in the finin mode, the signal of signal level "1" is output to the signal line 44g. Then, the NACK signal detection circuit 38 detects the NACK signal. When the NACK signal is detected, the signal of the signal level "1" is output to the signal line 44b and the transmission of the image transmission is interrupted. The retransmission start line number sent after the NACK signal is input by the retransmission start line detection circuit 39.

When performing retransmission, the retransmission start line number is output to the signal line 44c, and the encoding circuit 28 is notified of the retransmission start line number. Then, the signal of the signal level "0" is output to the signal line 44b to perform the retransmission from the retransmission start line number.

In step S66, the signal on the signal line 40a is input to check the presence or absence of the next original. If there is a next manuscript, step S6
On the other hand, if there is no next original, the process proceeds to step S68.

Step S68 represents a post-procedure conforming to CCITT Recommendation T30. Here, the telephone call is made by inputting the signal on the signal line 42a and transmitting the PRI-EOP signal as recommended by T30 when the telephone reservation is made.

Step S70 represents a pre-procedure conforming to CCITT Recommendation T30. Here, the 51st bit of FIF in the NSS signal is “0”
And

Step S72 represents message transmission conforming to CCITT Recommendation T4.

Step S74 represents a post-procedure conforming to CCITT Recommendation T30.

When the receiver detects an error, it is possible to reduce the transmission speed and fall back.

Also, as a countermeasure when the NACK signal sent from the receiver cannot be detected when the transmitter is transmitting image signals, a certain time (for example, 10
It is also possible to control to return to the procedure once when the time exceeds (minutes) (that is, send the MPS signal or EOM signal if there is the next original).

〔The invention's effect〕

As described above, according to the present invention, in the facsimile communication method using the CCITT recommended G3 procedure signal, the transmitting side transmits the image data of the next page after the RTC signal indicating the end of the image data of one page. After notifying the receiving side with the NSS signal, the transmission of image data is started and
After sending the page image data, send the RTC signal and
When the NSS signal informs the receiver that the next page of image data will be sent after the TC signal and the receiver will send the next page of image data after the RTC signal, After the reception is completed, the signal received subsequently to the RTC signal is received as the image signal of the next page, so that the procedure time can be shortened and the procedure stability can be increased.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a procedure between facsimile apparatuses to which the present invention is applied, FIG. 2 is a diagram showing an example of a procedure between conventional facsimile apparatuses, and FIG. 3 is an encoding example to which the present invention is applied. FIG. 4 is a diagram showing an example of a signal to which the present invention is applied, FIG. 5 is a block diagram showing an embodiment of a facsimile apparatus to which the present invention is applied, and FIG. 6 is shown in FIG. 7 is a flowchart showing a control procedure to be executed by the control circuit 44 shown. 20 …… NCU, 22 …… telephone, 24 …… hybrid circuit, 2
6 …… reading circuit, 28 …… encoding circuit, 30 …… V27ter or V29 modulator, 32 …… V21 modulator, 34 …… echo suppressor function tone generation circuit, 36 …… adding circuit, 37
V21 demodulator, 38 NACK signal detection circuit, 39 retransmission start line detection circuit, 40 document presence detection circuit, 41
Mode selection detection circuit, 42 ... Telephone reservation presence / absence detection circuit,
43 ... Operator calling circuit, 44 ... Control circuit.

Claims (1)

[Claims] 1. A facsimile communication method using CCITT-recommended G3 procedure signals, in which the NSS sends the image data of the next page after the RTC signal indicating the end of the image data of one page on the sending side.
After notifying the receiving side with a signal, the image data transmission is started, the RTC signal is transmitted after the transmission of the image data of one page is completed, and the image data of the next page is transmitted following the RTC signal. , When the sending side notifies that the image data of the next page is sent following the RTC signal by the sending side,
A facsimile communication method characterized in that after the reception of the image data of one page, the signal received subsequently to the RTC signal is received as the image signal of the next page.