JPH0453348B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a facsimile communication procedure system.

Conventional technology The conventional standard facsimile communication procedure was CCITT
This is stipulated in Recommendation T30, and the procedure is shown in Figure 3. In the procedure specified in T30, the training check signal TCF and the facsimile message signal MSG are separate and independent signals, and
The facsimile message signal MSG is further independently divided into pages. Each of these signals includes a training signal necessary for the modem to initially receive the signal.

Problems to be Solved by the Invention However, in the conventional facsimile communication procedure system described above, the training check signal TCF
Since the fax and facsimile message signals MSG are treated as independent signals, the modem must perform reception training operations on each signal. For this reason, as a condition of the communication line, if the line is close to the operating limit of the modem, the reception status may differ depending on the training check signal TCF, facsimile message signal MSG, and page, and it is not possible to communicate using the training check signal TCF. Facsimile message signal even if it can be determined
There were times when it was not possible to communicate with MSG, which was a cause of communication errors.

The present invention has been made in view of the above-mentioned conventional circumstances, and therefore, an object of the present invention is to provide a new facsimile communication procedure system capable of solving the above-mentioned problems of the conventional art.

Means for Solving the Problems In order to achieve the above object, the facsimile communication procedure system according to the present invention uses the training check signal TCF and facsimile message signal of the Group 3 facsimile communication procedure specified in T30 of the CCITT recommendation. Using a series of high-speed data signals combined with MSG, receipt confirmation signal CFR, message confirmation signal MCF and training failure signal
FAX message signal equivalent to FTT
It consists of a full-duplex communication procedure using a single tone outside the MSG frequency band.

The signal combining the above training check signal TCF and facsimile message signal MSG first has a training signal for the receiving modem, and then a training check signal
A data string corresponding to TCF and a data string corresponding to facsimile message signal MSG continue, but the data string corresponding to training check signal TCF continues until a tone corresponding to reception confirmation signal CFR or training failure signal FTT is confirmed. , in the case of a tone corresponding to the acknowledgment signal CFR, then the facsimile message signal
The MSG data string is transmitted, and if the tone corresponds to the training failure signal FTT, it is interrupted and the process moves to retransmission. In the case of multi-page, the frame of the multi-page signal is transmitted in the facsimile message signal MSG after the data string of the facsimile message signal MSG, and when the tone corresponding to the message confirmation signal MCF is confirmed, the frame of the multi-page signal is transmitted after the data string of the facsimile message signal MSG. Transmit MSG data string.

As described above, the training check signal is
The TCF and facsimile message signal MSG is now a series of high speed data signals, and the MSG
It becomes possible to provide a facsimile communication procedure that solves the problem that only signals cannot be received.

Embodiment Next, a preferred embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the facsimile communication procedure of the present invention. In the present invention, the training check signal
Mixed signal of TCF and facsimile message signal MSG, reception confirmation signal CFR, multi-page signal MPS
Or a single tone (hereinafter a signal with a positive meaning) outside the frequency band of the facsimile message signal MSG corresponding to the training failure signal FTT.
The tone corresponding to CFR and MCF is abbreviated as TONE2, and the tone corresponding to the training failure signal FTT having a negative meaning is abbreviated as TONE1. In addition, TONE
1 and 2 are tones with the same frequency and different length), full-duplex communication is required, so the output signal of the modem 11 is transmitted in order to prevent malfunction of the TONE 1 and 2 detection circuit 20 on the receiver side R. , passes through a low-pass filter 12 that removes the frequency components of TONE 1 and 2, is combined with the output of the tone generation circuit 18 that creates TONE 1 and 2 in a synthesis circuit 13, and is output to the line LINE through an amplifier circuit 14 and a hybrid circuit 15. be done. The signal input from the line LINE is
Through the hybrid circuit 15 and the amplifier circuit 16,
After that, the modem 1 passes through a low-pass filter 17 that removes unnecessary band components (including TONE 1 and 2) in the modem 11.
1 and the other is input to the tone detection circuit 20 through a bandpass filter 19 that passes only TONE 1 and 2. The above configuration enables full-duplex communication according to the present invention.

Next, the communication procedure of the present invention will be explained using FIG. 3 of the conventional communication procedure and FIG. 2 of the communication procedure of the present invention (shaded areas in FIGS. 2 and 3 represent high-speed data signals).

Conventionally, the training check signal TCF and the facsimile message signal MSG are independent signals as shown in FIG. 3, but in the present invention, they are treated as a series of high-speed data signals. This signal is sent at the same timing as the training check signal TCF. Training check signal after training signal
The TCF data string is sent out until TONE 1 or 2 is detected or a certain period of time has elapsed.
When TONE2 is detected, a facsimile message signal is sent following the data string of signal TCF.
When the MSG data string is transmitted and TONE 1 is detected or a timeout occurs, the high-speed data signal is interrupted and a retransmission procedure is performed. Receiver side R
Then, the data string corresponding to the training check signal TCF is checked, and if an error is detected, TONE1 is sent out, and after carrier interruption is confirmed, the retransmission procedure is performed. If there is no error, TONE2 is sent out and the data string of the facsimile message signal MSG is received.

In the case of multi-page, the transmitter side T
As shown in the figure, after the signal MSG data string, a frame of the multi-page signal MPS is sent as a high-speed data signal, and when TONE2 is detected, the next page signal MSG
The data string is transmitted, and when TONE 1 is detected, the high-speed data signal is interrupted and the process returns to 300 bps procedural signal communication.

When the receiver side R detects the signal MPS data frame after the signal MSG data string,
Send TONE 2, receive the next page of MSG data, and if you cannot detect an MPS data frame or want to return to the 300bps procedure signal, send TONE 1 and wait until the high-speed data signal is interrupted. Wait and go back to the 300bps procedure.

As described above, by incorporating the training check signal TCF into the facsimile message signal MSG, when it is determined that the signal TCF can be received, subsequent signals MSG can be transmitted in the same state. It is possible to provide a facsimile communication procedure that solves the problem of not being able to receive only the signal MSG.

Effects of the Invention As explained above, according to the present invention, in order to treat the training check signal TCF and the facsimile message signal MSG as a series of high-speed data signals in combination, the signals TCF and MSG are processed by one training signal. received and transmitted in the same reception state. Furthermore, in multi-pages, the reception status between pages is kept constant because high-speed data communication is not interrupted even between pages.
For this reason, conventionally, on lines near the modem's operational limit, the reception status of the training check signal TCF and the facsimile message signal MSG was different, and even if it was determined that communication was possible using the signal TCF, there were cases where communication using the signal MSG was not possible. However, according to the present invention,
If it is determined that communication is possible using the signal TCF, the signal MSG is received in the same reception state, and the effect of reliably transmitting the signal MSG is obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of a communication procedure according to the present invention, and FIG. 3 is a diagram showing an example of a conventional communication procedure. Note that the shaded portions in FIGS. 2 and 3 indicate communication of high-speed data signals. The MPS in FIG. 2 is a high-speed data signal with the same content as the MPS data frame in FIG. 3. In Figures 2 and 3, a
indicates an initial procedure, and b indicates a multi-page procedure. 11...Modem (MODEM), 12, 17...Low pass filter (LPF), 13...Signal synthesis circuit (MIX), 14, 16...Amplification circuit (AMP), 15
...Hybrid circuit (HYB), 18...Tone generation circuit, 19...Band pass filter (BPF), 20
…Tone detection circuit, CED…Called station identification signal
(2100Hz tone), NSF…Non-standard equipment signal (Non-standard equipment signal)
−standard facilities) (300bps), CSI…called subscriber identification signal (called subscriber identification signal)
identification) (300bps), DIS…Digital identification signal
(300bps), TSI...Transmitting subscriber identification signal
(300bps), NSS...Non-standard equipment setting signal ((Non-
standard set-up) (300bps), DCS...Digital command signal
(300bps), FTT...Failure to train (300bps), CFR...Confirmation to receive (300bps),
MPS…Multi-page signal
(300bps), MCF…Message confirmation signal (300bps), RTN…Retrain request signal (Retrain negative)
(300bps), TCF...Training check signal (high-speed data signal), MSG...
Facsimile message signal
Message) (high-speed data signal).

Claims (1)

[Claims] 1 Using a series of message data rate transmission signals that combine training check signals and facsimile message signals in the Group 3 communication procedure specified in CCITT Recommendation T30,
A facsimile communication procedure system characterized by full-duplex communication in which a single tone outside the frequency band of the facsimile message signal is used instead of a reception confirmation signal of a response signal, a message confirmation signal, and a training failure signal.