JP3518245B2 - Communication control method and communication terminal device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication control method and a communication terminal device between communication terminal devices such as facsimile machines, and more particularly to full-duplex communication such as ITU-T (International Telecommunication Union). -When performing data communication such as facsimile communication in accordance with Recommendation V.34 of the Telecommunications Standardization Division), training of the primary channel (channel for data communication), which is the pre-procedure for full-duplex communication, has been completed. The present invention relates to a communication control method and a communication terminal device that facilitate recovery when data that should originally be transmitted / received cannot be normally received.

[0002]

2. Description of the Related Art Generally, a communication terminal device for performing data communication such as a facsimile device converts a digital signal into a voice signal at the time of transmission and transmits the voice signal to a general public telephone line, and at the time of reception, a voice signal from the general public telephone line. A modem (modem) for receiving a signal and converting it into a digital signal is provided.

When performing data communication with a conventional communication terminal device, a modulation / demodulation device conforming to a half-duplex method, for example, ITU-T (International Telecommunication Union-Telecommunications Standardization Sector) Recommendation V.17 communication procedure is recommended. It is used according to the procedure stipulated in Recommendation T.30, which is also a general G3 standard facsimile communication procedure.

[0004]

When performing data communication such as the above-mentioned facsimile communication, after the communication procedure is established between the transmitting and receiving devices, the transmission of the data which is the original communication content is started from the transmitting side device. However, if this image data cannot be normally received by the receiving side device within a predetermined time, a communication error occurs and the line is disconnected. In such a case, even if the line status is only temporarily bad, the user has to redial and repeat the facsimile communication operation from the beginning, which is troublesome.

By the way, in recent years, an ultra-high-speed full-duplex communication procedure (hereinafter referred to as V.34 communication procedure) conforming to the recommendation V.34 and having a maximum transmission rate of 33.6 Kbps has been put into practical use. In such full-duplex communication, it is possible to transmit a signal from the other device and receive the signal at the one device even while the signal is being transmitted from the one device to the other device. Therefore, if the communication procedure as described above is already established,
It is possible to continue communication without disconnecting the line by causing the receiving side device to act on the transmitting side device.

The present invention has been made in view of the above circumstances. For example, when data communication such as facsimile communication is performed between devices capable of full-duplex communication such as V.34 communication procedure, full-duplex communication is performed. If the image data cannot be received normally at the receiving device after the training of the primary channel for heavy communication is completed, disconnect the line by requesting that the receiving device re-execute the training of the primary channel. An object of the present invention is to provide a communication control method and a communication terminal device capable of continuing communication without any communication.

[0007]

SUMMARY OF THE INVENTION A communication control method according to the present invention is a full-duplex communication in which a transmitting and receiving device trains a primary channel for transmitting and receiving data that should originally be transmitted and received, and then transmits and receives the data. In the communication control method for performing the above, when the receiving side device cannot receive the data, it is possible to request the transmitting side device to re-execute the training of the primary channel.

In such a communication control method of the present invention, when the data to be originally transmitted / received is not normally received by the receiving side device , the receiving side device transmits the primary data to the transmitting side device. Request rerun of channel training.

Further, the communication control method according to the present invention transmits the signal requesting re-execution of the training of the primary channel in the receiving side device when the original data transmitted from the transmitting side cannot be detected within a predetermined time. It is characterized by doing.

In such a communication control method of the present invention, when the data to be originally transmitted / received is not normally received by the receiving device within a predetermined time, the receiving device training the primary channel to the transmitting device. It is possible to request re-execution of.

Further, the communication terminal device according to the present invention is a communication device for performing full-duplex communication for receiving data after training of a primary channel for transmitting and receiving data that should originally be transmitted and received between the transmitting and receiving sides. Detect that it cannot receive the data
And means that the means cannot receive the data.
And a means for transmitting a request signal for requesting re-execution of the training of the primary channel to the transmitting side device when it is detected .

In such a communication terminal device of the present invention, when it becomes a receiving side device ,
If the signal can not be received, a signal requesting the re-execution of the primary channel training is transmitted to the transmitting side apparatus, and the transmitting side apparatus re-executes the primary channel training accordingly.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the drawings showing the embodiments thereof. FIG. 1 is a block diagram showing a specific configuration example when the communication terminal device according to the present invention is applied to a facsimile device.

In FIG. 1, reference numeral 1 indicates a CPU (central processing unit) which functions as a control unit of a facsimile machine, and a ROM (Read) which stores a program for controlling the operation of the entire facsimile machine in advance. Only Memor
y) 2 is connected to a RAM (Random Access Memory) 3 that functions as a storage unit that stores data required for control by the CPU 1 or data that needs to be temporarily stored during operation.

Further, the CPU 1 has an NCU (Network Control U
nit) 4 and modem 5 are connected. NCU 4 is CPU 1
Under the control of the line L and the facsimile device, and has a function of transmitting a dial pulse corresponding to the telephone number of the communication partner and a function of detecting an incoming call. The line L is connected to a general public telephone line (not shown).

The modem 5 modulates / demodulates the transmitted / received data, specifically, modulates the transmitted data into a voice signal and sends the voice signal to the line L via the NCU 4, and conversely the voice received from the line L via the NCU 4. Demodulate the signal into a digital signal. As the modem 5, there are products with various capabilities, but in this example, it is assumed that the modem is capable of performing V.34 communication procedures compatible with full-duplex communication.

The CPU 1 is further connected to a reading unit 6, an image memory 7, a codec 8, a recording unit 9, an operating unit 10, a display unit 11 and the like. The reading unit 6 reads a document image using, for example, a CCD image sensor. The image memory 7 stores the image data read by the reading unit 6 and also the image data received from the outside via the line L and the modem 5. The codec 8 encodes image data to be transmitted and decodes the received image data. Recording unit 9
Records the received image data or the image data read by the reading unit 6 on a recording paper (paper). The operation unit 10 is composed of a numeric keypad for inputting numbers such as a telephone number, a one-touch key, a shortening key, and operation keys for instructing various operations. The display unit 11 is configured by a CRT display or an LCD (liquid crystal display device) that displays various information such as a telephone number input by operating the operation unit 10.

Next, regarding the operation of the facsimile apparatus which is the communication terminal apparatus of the present invention having the above-described configuration, that is, the procedure of the method of the present invention, the control procedure by the CPU 1 in the receiving side (callee side) apparatus This will be described below with reference to the flowcharts of FIGS. In the following description, it is assumed that the transmission side (calling side) device also has the same function.

First, when communication is started after receiving a call,
The pre-procedure according to the V.8 communication procedure is performed to determine the actual communication speed (step S11).

Next, probing and equalizer training are performed according to the V.34 communication procedure (step S1).
2). This is a primary channel which is a channel for data communication by exchanging information such as modem capability, line probing result, data mode modulation parameter, etc. between both the transmitting side and receiving side devices, and further transmitting and receiving training signals. Training is performed to determine the communication speed.

After that, facsimile communication (T.30 communication procedure in this embodiment) compliant with ITU-T Recommendation T30 is started (step S13). When the signal of the T.30 communication procedure is normally received from the transmitting side device within the predetermined time (step S14
"YES" in step S20, "NO" in step S20), the receiving device is T.
30 Transmission is performed according to the communication procedure (step S15). As a result, the pre-procedure of the T.30 communication procedure, which is facsimile communication, is completed, and the original image data can be transmitted and received.Therefore, the transmission side device starts transmitting the image data and the receiving side device Receive (step S16).

The receiving side apparatus receives the signal of the T.30 communication procedure after the reception of the image data of the facsimile communication ("YES" in step S17), and correspondingly the T.30.
The communication procedure is transmitted (step S18).
If it is received again by the T.30 communication procedure (step S1
9), the entire process ends as the facsimile communication ends.

It should be noted that the CPU 1 of the receiving side device executes step S1.
If the reception according to the T.30 communication procedure in 7 is not performed within the predetermined time (“NO” in step S17 ), the processing is interrupted as a communication error.

By the way, in the case where the receiving side device cannot normally receive the image data in step S16,
This will be described with reference to the flowchart of FIG. 3 showing the details of the processing in step S16.

Firstly CPU 1 waits a predetermined until it receives a valid image data time (step S31 and step S 4
1). When valid image data is received within the specified time ( step
Tsu in step S31 during the "NO" in the flop S41 "YES"), then CPU 1 determines whether the high-speed signal (G3 or higher)
(Step S32) If the signal is not a high-speed signal (Step S32
”NO”) Perform predetermined processing (FSK reception) (step S
33). If it is high-speed communication ("YES" in step S32)
)), The CPU 1 then performs an FCS error check (step S34), and if no FCS error has occurred (“YES” in step S34), checks whether an RTC signal has been received (step S35). ), And whether or not an RCP frame has been received (step S36).
When the TC signal is received (“YES” in step S35) or when the RCP frame is received (step S36), the process proceeds to step S17 described above.

When neither the RTC signal nor the RCP frame is received (“NO” in both steps S35 and S36)
CPU1 is a unit sent from the sending device.
A process of receiving (usually one page) image data and fetching the image data is performed (step S37), and the process returns to step S31 to receive the next unit of image data.

On the other hand, when valid image data cannot be received within the predetermined time in step S31 (in step S31 , "
If "YES" in step S41 during "NO" and if an FCS error has occurred ("NO" in step S34), the primary channel retrain process characterizing the method of the present invention is performed (step S42).

FIG. 4 is a time chart showing the procedure of the primary channel retrain process in step S42.

In the receiving side device, when the normal reception of the image data cannot be performed within the predetermined time, the tone B is transmitted,
Wait for tone A to be transmitted from the transmitting device. When the tone A is received, the tone B is transmitted for at least 50 milliseconds, then the tone B inversion signal is transmitted for 10 milliseconds, and the transmission side apparatus waits for the tone A inversion signal to be transmitted. On the other hand, the transmitting side device transmits the inverted signal of tone A, then transmits probing signal L1 for 10 milliseconds and L2 for 160 milliseconds, and then transmits tone A.

When the receiving side device receives the inverted signal of tone A, it enters a state of waiting for the probing signals L1 and L2, and when both are received, it transmits tone B and then transmits INFOh for notifying communication parameters for 25 milliseconds. To do.

Upon receiving this INFOh, the transmitting side device starts the equatorial training of the primary channel. The transmitting device first transmits the signal S for 128T, then the inverted signal S for 16T, and then the signal PP for 288T.
And the signal TRN is transmitted. In addition, it is necessary to be within 2000 milliseconds from the start of transmission of the signal PP to the end of transmission of the signal TRN.

As described above, when the transmitting side device sequentially transmits the signal S, its inverted signal, PP and TRN, the receiving side device detects the signal S and its inverted signal to detect the next detected signal PP. And TRN to train the primary channel. After transmitting the signal TRN for the period designated by INFOh, the receiving side device transmits the control channel and image data. The image data is received again by the receiving device according to the flowchart of FIG. By such a primary channel retrain process of step S42 of the method of the present invention, the T.30 communication procedure, which is the facsimile communication, can be restarted without disconnecting the line even if the line is disconnected once in the past. Will be possible.

In the above embodiment, the case where the V.34 communication procedure is applied to facsimile communication has been described, but it goes without saying that the present invention can be applied to general full-duplex communication. The case where the data transmitted by the V.34 communication procedure is the image data of the facsimile communication has been described, but it goes without saying that it may be other digital data.

[0034]

As described above in detail, according to the communication control method of the present invention, all the data transmission / reception is performed after training of the primary channel for transmitting / receiving the data originally transmitted / received between the transmission / reception devices. When performing duplex communication, the data that should originally be transmitted / received is the receiving device.
If in is not received correctly, since it is possible to request if necessary the re-execution of the primary channel training to the transmitting-side apparatus from the receiving apparatus, a single
If the line status is temporarily poor, the line will be disconnected.
Communication is continued without performing the
Reception is re-executed .

According to the communication control method of the present invention,
When data that should be transmitted and received by the receiving device is not normally received by the receiving device within a predetermined time, the receiving device can request the transmitting device to re-execute the primary channel training. Become.

Further, according to the communication terminal device of the present invention,
In a communication device that performs full-duplex communication that receives data after training of a primary channel for transmitting and receiving data that should originally be transmitted and received between the transmitting and receiving sides, if data cannot be received , Since it is possible to send a request signal for re-execution of the primary channel training to the sending side device before receiving, disconnect the line if the line status is only temporarily defective. communication as it is continued without reception of data is re-executed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration example of an embodiment in which a communication terminal device of the present invention is embodied as a facsimile device.

FIG. 2 is a flowchart showing a procedure of a communication control method of the present invention executed by a communication terminal device of the present invention.

FIG. 3 is a flowchart showing a procedure of a communication control method of the present invention executed by the communication terminal device of the present invention.

FIG. 4 is a time chart showing a procedure of a primary channel retrain process of the communication control method of the present invention.

[Explanation of symbols]

1 CPU, 5 modems, L communication line.

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) H04L 29/08 H04N 1/32

Claims (3)

(57) [Claims] 1. A communication control method for performing full-duplex communication for transmitting and receiving the data, after training of a primary channel for transmitting and receiving the data that should originally be transmitted and received between the transmitting and receiving devices. The communication control method, wherein when the data cannot be received, the transmitter device can be requested to re-execute the training of the primary channel. 2. The receiving side device transmits a signal requesting re-execution of training of a primary channel when original data transmitted from the transmitting side cannot be detected within a predetermined time. Claim 1
The communication control method described in. 3. A communication device for performing full-duplex communication for receiving the data after training of a primary channel for transmitting / receiving the data that should originally be transmitted / received between the transmitting / receiving sides, can receive the data.
Means for detecting the inability to
And a means for transmitting a request signal for re-execution of the training of the primary channel to the transmission side device when it is detected that it cannot be received .