JP2762456B2 - Facsimile machine - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a facsimile apparatus, and more particularly, to a facsimile apparatus conforming to CCITT recommendations T.30 and T.4 (G3 standard).

(Prior Art) First, a sequence of a binary code signal of a G3 standard facsimile apparatus will be described.

FIG. 5 is a diagram showing a sequence of a binary code signal of CCITT Recommendation T.30.

 The names of the abbreviations shown in the figure are as follows.

CED: Called station identification signal DIS: Digital identification signal DCS: Digital command signal TRN: Training sequence signal TCF: Training check signal CFR: Reception preparation confirmation signal FTT: Training failure signal PIX: Image information (message) EOP: Procedure end signal MCF: Message confirmation signal DCN: Line disconnect command signal In FIG. 5, after the receiver replies DIS, DCS, TRN and TCF (first TRN and TCF)
TCF) is output. This TRN equalizes the modem (modulator / demodulator) on the receiver side (determines the equalizer coefficient of the modem), and the TCF (1.5-second continuous "0" signal) allows the modem to be satisfactorily equalized. Is confirmed.

The first output of TRN and TCF is performed at the maximum transmission speed of the facsimile apparatus.

If this training is performed successfully, the CFR is output from the receiver, and then the TRN is again output from the transmitter.
After (TRN immediately before image information) is output, PIX transmission is started.

In such a situation, the TRN after the CFR and before the image information
The equalization of the modem on the receiver side is confirmed (re-equalized), and the convergence of the equalizer coefficients is further improved, so that the reception state of the image information is further improved.

By the way, when the training is not properly performed by the first TRN and TCF, the FTT is output from the receiver side as shown in FIG. Then, from the transmitter side, the DCS, TRN and TCF (the second T
RN and TCF) are output.

The second TRN and TCF are performed at the same transmission rate as the first TRN and TCF, or at a lower transmission rate. If communication is performed at a low transmission rate, the possibility of communication can be increased. Slow transmission speed after training failure
The function of sending TRN and TCF is called the automatic fallback function.

If the second reception of TRN and TCF is performed well (that is, if training is successful), the receiver side
If CFR is output and reception is still not good,
The FTT is output again, and further training is performed.

When an FTT is output from the receiver, the line (subscriber telephone line) has a lot of noise and is often poor.
In this case, even if training is successful with the second and subsequent TRNs and TCFs, the TRNs after the CFR (in other words, the TNs immediately before the PIX)
RN) and / or PIX may be mixed with noise, and the receiver-side modem may not be re-equalized / converged (ie, diverged). In this case, the PIX
Is transmitted, the receiver cannot receive it normally.

To prevent this problem, the equalizer coefficient is held,
A facsimile apparatus configured to prohibit TRN before image information after CFR has been proposed.

(Problem to be solved by the present invention) As described above, the TRN before the image information after the CFR confirms (re-equalizes) the equalization of the modem on the receiver side and checks the convergence of the equalizer coefficient. To do better.
With this TRN training, P
The reception of IX can be performed in the best possible condition.

By the way, when the line is good, it can be assumed that there is not much noise in the communication information.Therefore, there is a possibility that modem re-equalization and convergence cannot be performed by demodulator training by TRN before image information after CFR. rare.

However, in a facsimile apparatus configured to prohibit TRN before image information after CFR, when CFR is output with the first training and TCF reception signal is good, that is, even when the line is good, Training before the image information after the CFR is prohibited.

Therefore, in the conventional facsimile apparatus as described above, there is no possibility that image information cannot be received, and even when the line is good, training that should not be prohibited is prohibited. As a result, what is supposed to be able to receive image information in the best condition cannot be performed in the best condition.

The present invention has been made to solve the above problems.

(Means and Actions for Solving the Problems) In order to solve the above-described problems, the present invention provides a line state determining unit that determines a communication line state, and a communication line state determined by the line state determining unit. A training execution unit for performing training immediately before the image information message after CFR when the communication line state determined by the line state determination unit is lower than the predetermined reference; And a training prohibition unit for prohibiting the training immediately before the image information message.

Thereby, when the line condition is good, the training using the TRN before the image information after the CFR is performed, and when the circuit condition is bad, the training using the TRN immediately before the image information after the CFR is prohibited, The function and effect of creating a stable demodulation state can be produced.

(Example) Hereinafter, the present invention will be described in detail with reference to the drawings.

 FIG. 2 is a schematic block diagram of one embodiment of the present invention.

In FIG. 2, reference symbol D denotes an image information data bus, and reference symbol C
Indicates a control bus.

A reading processing unit 1 for reading image information from a document and a recording processing unit 2 for recording received image information are connected to a line memory control unit 3.

The line memory control unit 3 is connected to the information compression / decompression unit 4, the information compression / decompression unit 4 is connected to the communication control unit 5, the communication control unit 5 is connected to the modem 6, and the modem 6 is connected to the network control unit 7. .

In this example, the modem 6 has a function of holding an equalizer coefficient and a function of selecting training prohibition. Since the modem 6 having such a configuration is known, its description is omitted.

Further, the communication control unit 5 has a microcomputer, and in addition to the usual control of data transfer between the modem 6 and the information compression / decompression unit 4, as described later with reference to FIGS. Operation for activating the function of holding the equalizer coefficient and the function of selecting training prohibition of the modem 6 according to whether the CFR is transmitted or the FTT is transmitted after the reception of the TRN and the TCF. Perform

The line controller 3, the information compression / decompression unit 4, the communication control unit 5, the modem 6, and the network control unit 7 are controlled by a main control unit 9.

The network control unit 7 is connected to lines L1 and L2.
Further, the network controller 7 includes a telephone 8 if necessary.
Is connected.

FIG. 1 is a functional block diagram of one embodiment of the present invention.
In this figure, a control part of the communication control unit 5 for handling image information data is omitted because it has no linear relationship with the present invention.

In FIG. 1, a training state determination means 11 determines whether or not training has been successfully performed based on the TRN and TCF transmitted from the transmitter. This judgment signal is CF
The R / FTT signal transmission determining means 12, the equalizer coefficient holding control signal generating means 13, and the training inhibition control signal generating means 14 are supplied.

The CFR / FTT signal transmission deciding unit 12 responds to the output signal of the training state determining unit 11, that is, the main control unit 9 in accordance with whether or not the training is properly performed.
Then, a command (control signal) for transmitting CFR or FTT is transmitted. The CFR / FTT signal transmission determining means 12 can also receive an interrupt control signal from the main control unit 9, a request from the modem, and determine transmission of the CFR or FTT.

FTT signal transmission storage means 15, if a signal to transmit FTT or FTT is output from the CFR / FTT signal transmission determination means 12, stores that fact and the equalizer coefficient holding control signal generation means 13, and training prohibition control signal generating means 14
Output to

The training state determination unit 11, the CFR / FTT signal transmission determination unit 12, and the FTT signal transmission storage confirmation unit 15 constitute a line state determination unit 20.

The equalizer coefficient holding control signal generating means 13, when it is determined by the line state determination means 20 that the line state is not good,
That is, when it is determined by the training state determination means 11 that training has been successfully performed, and when a signal indicating that FTT is already output from the FTT signal transmission storage means 15 has been input, the modem For 6, the control signal for holding the equalizer coefficient is output.

Similarly, the training state prohibition control signal generating means 14
Also, when the line state determination unit 20 determines that the line state is not good, that is, when the training state determination unit 11 determines that training has been successfully performed, the FTT signal transmission storage unit When a signal indicating that the FTT has been output has already been input from 15, a control signal is output to the modem 6 to prohibit training by the TRN before the image information.

As is clear from FIG. 1, the TRNs after the second time
And if training is successful with TCF, ie F
When the signal indicating that the FTT has been output is output from the TT signal transmission storage unit 15, the equalizer coefficient of the modem 6 is retained, and the demodulator training by the TRN before the image information after the CFR is performed. It is forbidden.

If the first TRN and TCF have succeeded in training, that is, if no signal indicating that the FTT has been output is output from the FTT signal transmission storage unit 15, the holding of the equalizer coefficient of the modem 6 is performed. Prohibition of demodulator training by TRN before image information after CFR and CFR is not set.

The equalizer coefficient holding control signal generating means 13 and the training prohibition control signal generating means 14 are supplied with a determination signal from the training state determining means 11 indicating whether or not training has been successfully performed. But CFR /
A signal for transmitting the CFR output from the FTT signal transmission determining means 12 may be supplied to the equalizer coefficient holding control signal generating means 13 and the training inhibition control signal generating means 14.

FIG. 3 is a flowchart showing the operation of one embodiment of the present invention. For the sake of simplicity, this flowchart shows the CED from the receiver (ie, the facsimile machine).
And DIS are output and then executed.

First, in step S1, it is determined whether DCS has been detected.

If DCS is detected, the first TRN and TCF are received in step S2.

In step S3, it is determined based on the TRN and the TCF whether or not the training has been successfully performed.

If the training is successful once, the CFR is transmitted in step S9, and the TRN and PIX are received in step S10. By this TRN, the modem of the facsimile apparatus is re-equalized and converged, and PIX reception is performed in the best condition.

Then, in step S11, it is determined whether EOP has been detected.

If EOP is detected, after the MCF is transmitted in step S12 and the DCN is received in step S13,
The process ends.

In step S3, if training is not properly performed by the first TRN and TCF, the process proceeds to step S4.

In step S4, the FTT is transmitted, and in step S5, the DCF, and the TRN and TCF (second T
RN and TCF) are received. TRN and TCF after the second time
Is the same transmission rate as the previous TRN and TCF, or
Transmission rate lower than N and TCF.

In step S6, it is determined from the TRN and the TCF whether or not the training has been successfully performed.

If training fails, return to step S4 again,
The third and subsequent training sessions are performed.

If the training is successful, in step S7, the equalizer coefficient TAPS of the modem of the facsimile apparatus is held, and in step S8, the TR before the subsequent image information is stored.
N demodulator training is prohibited. Thereafter, the process proceeds to step S9 and subsequent steps. In this case, training is not performed even if the TRN is received in step S10.

FIG. 4 is a functional block diagram of another embodiment of the present invention, and is similar to FIG. Also, in FIG.
The same reference numerals as those in the drawings denote the same or equivalent parts, and a description thereof will not be repeated.

As is clear from the comparison between FIG. 4 and FIG. 1, in this embodiment, instead of the FTT signal transmission storage means 15,
Training unsuccessful storage means 16 is provided.

The training unsuccessful storage means 16 stores a signal output from the training state determination means 11 indicating that training is unsuccessful. This signal is output to the equalizer coefficient holding control signal generating means 13 and the training state inhibition control signal generating means 14.

In the embodiment having the above-described configuration, similarly to the embodiment described above with reference to FIG.
If the training is successful, that is, if a signal indicating that training is unsuccessful is output from the training unsuccessful storage means 16, the equalizer coefficient of the modem 6 is held and the TRN training is prohibited.

If the training is successful by the first TRN and TCF, that is, if a signal indicating that the training is unsuccessful is not output from the training unsuccessful storage unit 16, the equalizer coefficient of the modem 6 is calculated. Holding, and CF
The prohibition of training by TRN after R is not set.

In FIG. 4, in the equalizer coefficient holding control signal generating means 13 and the training prohibition control signal generating means 14, the training state determining means 11 receives a determination signal indicating whether or not training has been successfully performed. Although it is depicted as being input, the CFR signal output from the CFR / FTT signal transmission determination means 12 or the signal indicating that the CFR is transmitted, as described above with reference to the embodiment shown in FIG. May be supplied to the equalizer coefficient holding control signal generating means 13 and the training inhibition control signal generating means 14.

By the way, in the above description, the line state determination means 20, 2
1, both have been described as having training state determination means 11 and CFR / FTT signal transmission determination means 12,
The determination as to whether or not the training is successful leads to the determination as to whether to transmit the CFR or the FTT. Therefore, it is not necessary to consider the above means 11 and 12 separately.

In addition, the equalizer coefficient holding control signal generating means 13 and the training prohibition control signal generating means 14 hold the equalizer coefficient when the first training is not successful.
And that training is prohibited.

However, the present invention is not particularly limited to this, and is configured to set the holding of the equalizer coefficient and the setting of the training prohibition when the Nth training is not successful after the second training. Of course, it can be done. Since the configuration in this case can be easily created by those skilled in the art, the description thereof will be omitted.

In the above description, the modem 6 has the function of holding the equalizer coefficient and the function of selecting the prohibition of the training. However, the present invention is not particularly limited to this. Instead, a modem that does not have a function of holding equalizer coefficients and a function of selecting training prohibition may be used, and the above-described functions may be set by the communication control unit 5 or the like. Since the configuration in this case can also be easily created by those skilled in the art, the description thereof will be omitted.

Further, in the description relating to FIG. 2, the facsimile apparatus has been described as having the reading processing unit 1, but the present invention relates to the training of the image information receiving side, and the image information reading / sending function is particularly necessary. Not.

(Effects of the Invention) As is clear from the above description, according to the present invention, when the line condition is bad, the equalizer coefficient is retained, and the demodulation by the TRN before the image information after CFR is performed. When the training of the equalizer is prohibited and the line condition is good, the equalizer coefficient is not held and the T before the image information after CFR
Since the demodulator training by the RN is performed, the following effects are achieved.

In other words, if the line status is bad, T after CFR
The RN and the image information prevent a situation in which the modem diverges and the image information becomes unreceivable, and when the line condition is good, the convergence of the equalizer coefficient of the modem is further improved. And image information can be received in the best condition.

[Brief description of the drawings]

FIG. 1 is a functional block diagram of one embodiment of the present invention. FIG. 2 is a schematic block diagram of one embodiment of the present invention. FIG. 3 is a flowchart showing the operation of one embodiment of the present invention. FIG. 4 is a functional block diagram of another embodiment of the present invention. FIGS. 5 and 6 are diagrams showing sequences of binary code signals of CCITT Recommendation T.30. 5 Communication control unit 6 Modem 11 Training state determination unit 12 CFR / FTT signal transmission determination unit 13
... Equalizer coefficient holding control signal generation means, 14 ... Training inhibition control signal generation means, 15 ... FTT signal transmission storage means, 16 ... Training unsuccessful storage means, 20, 21 ... Line state determination means

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) H04B 3/00-3/44 H04B 3/50-3/60 H04N 1/32-1/36

Claims (2)

(57) [Claims] The present invention has a modem capable of following and updating and fixedly holding its equalizer coefficient by training.
A facsimile apparatus that performs communication using a transmission procedure signal of T.30, comprising: a line state determining means for determining a communication line state in a DCS / TRN / TCF sequence; and a communication line determined by the line state determining means. When the state is better than a predetermined standard, training execution means for executing training immediately before the image information message after CFR, When the communication line state determined by the line state determination means is worse than the predetermined standard, A facsimile apparatus comprising: training prohibiting means for prohibiting training immediately before an image information message after CFR. 2. The DCS / TRN / TCF sequence is a CCITT recommendation.
2. The facsimile apparatus according to claim 1, wherein the first sequence is a T.30 transmission procedure signal.