JP3806274B2 - Data transmission apparatus and data transmission method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a data transmission apparatus and a data transmission method that operate in accordance with a communication procedure defined by ITU-V34 recommendation.
[0002]
[Prior art]
In recent years, in this type of data communication apparatus, V.D. Data communication is performed using 34 modems (28.8 kbps). For example, V. T30ANEXF (so-called Super G3) is recommended by ITU-T as a facsimile communication standard using a 34 modem, and image data communication is performed in accordance with this communication standard.
[0003]
The communication procedure will be described based on the sequence diagram shown in FIG. FIG. 9 is a control signal diagram of a pre-procedure for facsimile communication according to the prior art.
[0004]
In FIG. 9, 9a is a communication procedure for selecting a modulation mode from V34 half duplex, V34 full duplex, V17 half duplex and the like. 9b is a communication procedure related to line probing for inspecting the line and determining various parameters. 9c is a communication procedure for modem training. 9d is a communication procedure for setting modem parameters. 9e is a communication procedure of the facsimile control signal. 9f is a data communication procedure of the main channel. The upper side of the figure is the calling side sequence and the lower side is the called side sequence, and the sequence proceeds from left to right.
[0005]
The communication procedure as described above will be described more specifically.
[0006]
First, after the line connection, in the communication procedure 9a for selecting the modulation mode, V. 21 modems (300 bps, full duplex) select a modulation mode and a communication protocol that can communicate with each other on the calling side and the called side. V. In a facsimile machine using a 34 modem, V.V. 34 Modem, Facsimile communication is selected as the communication protocol.
[0007]
Thereafter, in the communication procedure 9b for line probing, a line probing tone is transmitted from the calling side, received at the called side, and line inspection is performed, and a training parameter is selected based on the line inspection result.
[0008]
In the modem training communication procedure 9c, the training signal is transmitted from the calling side based on the training parameter selected in the communication procedure 9b for line probing, and the training signal is received on the called side to correct the line characteristics. The learning of the filter coefficient of the adaptive equalizer and the reception quality check of the training signal are performed.
[0009]
In the communication procedure 9d for selecting the modem parameter, the modem parameter is negotiated between the calling side and the called side by a 1200 bps full-duplex modem, and the modem parameters set in advance in the apparatus and the above line inspection result Then, an optimum modem parameter is selected from the reception quality inspection of the training signal.
[0010]
In the facsimile control signal communication procedure 9e, the facsimile control signals NSF, CSI, DIS, TSI, DCS, CFR, etc. are negotiated by a 1200 bps full-duplex modem.
[0011]
In the data communication procedure 9f, the image data is transmitted from the calling side by the half-duplex modem from 2400 bps to 28.8 kbps, and the image data is received by the called side. When communicating at a maximum communication speed of 28.8 kbps, image data can be communicated in about 3 seconds per A4 sheet. The modem performs communication according to the training parameter selected in the communication procedure 9b for communication line probing and the modem parameter selected in the communication procedure 9d for modem parameter selection. The receiving modem performs communication using the filter coefficient learned in the modem training 9b in order to correct the line characteristics. Through the series of control procedures described above, optimum data communication according to the line quality is performed.
[0012]
[Problems to be solved by the invention]
However, in the configuration of the above-described prior art, since the pre-procedure for 5 channels is required from the line connection to the start of image data transmission, about 7 seconds are required. On the other hand, since the transmission time of one image data at the maximum communication speed of 33.6 kbps is about 3 seconds, when transmitting one original, the total time is 11 seconds including about 1 second in the subsequent procedure. On the other hand, the pre-procedure rate reaches 60% or more. Since the time required for this pre-procedure increases as the number of transmissions / receptions increases, useless time and communication costs are generated.
[0013]
The present invention has been made in view of the above-described problems, and a data transmission apparatus capable of shortening the time of the pre-communication procedure by omitting a part of the pre-communication procedure which takes time such as setting of various parameters of the modem, and An object is to provide a data transmission method.
[0014]
[Means for Solving the Problems]
The data transmission device according to claim 1 of the present invention is a storage means for storing modem control information for each destination, and when the control information is stored in the storage means, a shortened communication procedure transition notification signal is transmitted. The communication control means for executing the abbreviated communication procedure and transmitting the normal communication procedure calling signal to execute the normal communication procedure when it is not stored is provided.
[0015]
With this configuration, when the control information is stored in the storage means, it is possible to immediately shift to the shortening procedure, and it is not necessary to acquire the modem parameters and the like necessary for communication in the communication procedure every time, so the communication time is shortened. can do.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a data communication apparatus according to an embodiment of the present invention will be described with reference to the drawings, taking a facsimile apparatus as an example. FIG. 1 is a basic block diagram of a facsimile apparatus according to an embodiment of the present invention.
[0017]
In FIG. 1, a reading unit 101 is a reading unit such as a scanner for reading a document image, and a recording unit 102 is an output unit such as a printer for recording and outputting a received image. The control unit 103 is a control unit for controlling the entire apparatus, and performs the execution control of the communication procedure in addition to the encoding and decoding processing of the image signal.
[0018]
The modem 104 is an ITU-T T.264. A modem for realizing all modulation and demodulation of facsimile communication procedures defined in 30ANEXF, a digital signal processing unit (DSP) 104a for performing modem signal processing, and an analog having both A / D conversion and D / A conversion functions And a front end portion (AFE) 104b. The line control unit 105 controls the line 106 such as dialing and calling.
[0019]
The operation unit 107 is an operation unit configured by various key input switches such as dial keys and start keys, a display device for displaying information, and the like.
[0020]
The memory 108 is a memory for storing information corresponding to a communication partner having a shortening procedure function. In this embodiment, information such as a telephone number and a modem parameter is stored. The stored modem parameters include a power suppression value indicating signal power, a time value indicating training time, carrier selection information for selecting one of two types of high level / low level, pre-emphasis filter selection information, Symbol speed selection information, training constellation point selection information, shoulder gain information for adjusting data modulation timing, and the like, in which five speeds are selected and set for the eye pattern.
[0021]
Next, the functional configuration of the digital signal processing unit (DSP) 104a of the modem 104 will be described with reference to FIG.
[0022]
The modem control unit 201 controls an interface with the control unit 103 and various modem functions. The modem control unit 201 has a plurality of functional units described below, which are usually executed by software.
[0023]
The tonal transmission function unit 202 transmits various tonal signals according to the communication procedure. The tonal detection unit 203 identifies a tonal signal transmitted from a communication partner. V. 21 modem 204 is an ITU-T recommendation V.21. 21-compliant modem (300 bps, full duplex). The INFO modem 205 is an ITU-T recommendation V.264. 34 is a modem (600 bps, full duplex) that performs INFO sequence communication conforming to 34, and is used in a communication procedure for line probing and a start procedure for a shortening procedure.
[0024]
The control channel modem function unit 206 is an ITU-T recommendation V.264. 34 is a control channel modem (1200 bps or 2400 bps, full duplex) defined in No. 34, and is used for setting modem parameters for the main channel modem and for communication procedures of facsimile control signals.
[0025]
The main channel modem function unit 207 is an ITU-T recommendation V.3. 34 is a main channel modem (2400 bps to 33.6 kbps, half duplex) defined in 34, and is used for communication of image data.
[0026]
The line probing transmission function unit 208 is a V. A line probing tone defined in 34 is transmitted. This line probing tone is a composite signal of 21 types of tonal signals from 150 Hz to 3750 Hz shown in FIG.
[0027]
The line probing reception function unit 209 receives the line probing tone from the communication partner and performs line inspection. Specifically, the line probing reception unit 209 performs spectrum analysis on the received signal using a fast Fourier transform algorithm, and selects an optimum symbol rate, carrier selection, and other modem parameters for the main channel modem 207.
[0028]
The training transmission function unit 210 is provided with A training signal of 34 modem is transmitted, and the training signal unit 211 receives the training signal from the communication partner and learns the filter coefficient of the adaptive equalizer for correcting the line distortion.
[0029]
A process for registering a shortened procedure according to the present invention for the facsimile apparatus having the above configuration will be described with reference to the sequence diagram shown in FIG.
[0030]
3a is a communication procedure for selecting a modulation mode, 3b is a communication procedure for line probing, 3c is a communication procedure for modem training, 3d is a communication procedure for setting modem parameters, 3e is a communication procedure for facsimile control signals, and 3f is data for sending image data Communication procedure.
[0031]
First, the communication procedure 3a for selecting the modulation mode will be described. The calling terminal transmits a calling station identification signal CNG, and in response thereto, the called terminal transmits a modified response tone signal ANSam. Thereafter, the calling terminal transmits a CM signal indicating functions such as a modulation mode and a communication protocol, and the called terminal transmits a JM signal indicating a common function capable of communication according to the received content of the CM signal. Send. When the calling side confirms the JM signal, it transmits a CJ signal and then shifts to communication procedure 3b for line probing. The called party also makes a transition to the communication procedure 3b for line probing after detecting the CJ while transmitting the JM. The CM signal, JM signal, and CJ signal are V. 21 modem 204 (300 bps, full duplex).
[0032]
Based on this exchange of communication procedures, for example, V. In a facsimile apparatus using a 34 modem, the above V.V. In addition to selecting the modulation mode by the 34 modem, facsimile communication can be selected as the communication protocol.
[0033]
Next, the communication procedure 3b for line probing will be described. The calling side terminal is set to V.V. 34 transmits the signal INFO0c indicating the modulation speed of the modem, the communication capability such as the carrier frequency, and the line probing tone signals L1 and L2. On the other hand, the called terminal transmits a signal INFO0a indicating the communication capability set in advance and receives a line probing tone.
[0034]
The line probing tone signal is a composite signal of 21 types of tonal signals from 150 Hz to 3750 Hz shown in FIG. 3, and the called terminal receives the line probing tone and performs spectrum analysis using a fast Fourier transform algorithm. The optimum symbol rate, carrier selection and other modem parameters for the main channel modem 207 are selected.
[0035]
Then, the called terminal selects a training parameter that can be communicated from the selected contents, the contents of the INFO0c signal and the INFO0a signal, and sets and transmits the INFO0h signal. The signals INFO0c, INFO0a, and INFO0h are communicated by an INFO modem 205 (600 bps, full duplex). In this communication procedure, as a response signal for synchronization, the calling side tone B, iB (180 degree phase with respect to tone B) and the called side tone A, iA (with respect to tone A) 180 degree phase) is used.
[0036]
Next, the modem training communication procedure 3b will be described. The calling terminal transmits training signals S, iS, PP, and TRN using the training parameters of the INFO0h signal. On the other hand, the called terminal performs learning of the filter coefficient of the adaptive equalizer for receiving the training signal and correcting the line characteristics, and the equalization capability analyzer performs the optimum training time and the noise power ratio SN. And calculate.
[0037]
Next, the communication procedure 3d for modem parameter setting will be described. The calling side terminal and the called side terminal transmit procedure synchronization signals PPh and ALT and modem parameters MPh related to data communication to the counterpart terminal, and also transmit the MPh reception confirmation signal E from the counterpart terminal. As a result, the MPh is exchanged between the calling side and the called side.
[0038]
The calling side MPh signal is a modem parameter set in advance in the calling side modem. The called-side MPh signal is a modem parameter selected from preset modem parameters, a line inspection result of the line probing tone reception, and the S / N ratio calculated from the training signal reception. The communication procedure for the modem parameter setting is performed using the control channel modem 206 (1200 bps, full-duplex modem).
[0039]
Next, the communication procedure 3c for the facsimile control signal will be described. First, a nonstandard procedure signal NSF, a called terminal identification signal CSI, and a digital identification signal DIS are transmitted from the called terminal to the calling terminal. At this time, the called terminal performs transmission by setting a flag indicating that the NSF has a shortened procedure function and the optimal training time calculated by the equalization ability analysis unit 407.
[0040]
On the other hand, after receiving the NSF, CSI, and DIS, the calling side confirms that the called terminal has the short procedure function installed in the NSF, and then transmits the transmitting station identification signal TSI and the digital command signal DSC. Send. At that time, the calling party sets an abbreviated procedure registration flag.
[0041]
After receiving the TSI and DCS, the called terminal transmits a reception preparation confirmation signal CFR. In cases other than the above, if either the calling terminal or the called terminal does not have the shortening procedure function, the shortening procedure registration flag is not set on the calling side. The communication procedure of the facsimile control signal is communicated using a control channel modem 206 (1200 bps, full duplex modem).
[0042]
Next, the data communication procedure 3d for the main channel will be described. In this case, communication is performed using modem parameters that satisfy both the calling side and the called side from the training parameter of the INFO0h signal and the MPh.
[0043]
The calling party transmits procedure synchronization signals S, iS, PP, and B1 of the main channel, and then transmits PIX (image data). The called party receives the procedure synchronization signals S, iS, PP, B1 and the subsequent PIX (image data). Communication here is performed by the main channel modem 207 (1200 bps to 28.8 kbps, half duplex). In particular, the receiving side main channel modem 207 is configured to perform reception while correcting the line distortion using the filter coefficient learned by the adaptive equalizer 402. When communicating at the maximum communication speed of 28.8 kbps on the main channel, communication can be performed in about 3 seconds per A4 sheet.
[0044]
As described above, the communication procedure at the time of registration of the abbreviated procedure is performed by a normal procedure as recommended by T30ANEXF of ITU-T. Various information necessary for executing the abbreviated procedure is registered in advance in the memory 108 of the calling terminal. Thus, communication can be performed using a shortened procedure from the next communication.
[0045]
Next, the communication procedure when executing the registered shortening procedure will be described with reference to the sequence diagram shown in FIG.
[0046]
4 is a communication procedure for starting a shortening procedure, 4c is a communication procedure for modem training, 4d is a communication procedure for setting modem parameters, 4e is a communication procedure for facsimile control signals, and 4f is a data communication procedure. It is.
[0047]
First, the communication procedure 4a for starting the shortening procedure will be described. The calling terminal transmits a calling station identification signal CNG, and in response thereto, the called terminal transmits a modified response tone signal ANSam. After detecting the ANSam signal, the calling terminal transmits a quick tonal signal QTS, detects a response signal tone A from the called terminal, and transmits tones B and QINFO. After detecting the quick tonal signal QTS from the calling side, the called side terminal transmits tone A and receives the QINFO from the calling side terminal.
[0048]
This quick tonal signal QTS serves as an instruction signal for shifting to the shortening procedure. The click tonal signal QTS has a repetitive pattern “001100110011... The reason for using such a tonal signal pattern is that the quick tonal signal QTS received by the receiver is changed to the ITU-T recommendation T.30. 30 signal pattern (“011110”) defined by the standard signal 30 and a tonal signal pattern of the calling menu signal CM (a signal pattern consisting of a 2-bit start bit “10”, data 8 bits, and a stop bit “1”). ) So that it can be clearly identified. In addition, since the quick tonal signal QTS is a tonal signal having the same modulation method as that of the calling menu signal CM, the receiver side determines whether the incoming tonal signal is the quick tonal signal QTS or the calling menu signal CM. It is possible to easily identify the communication in the shortened procedure or the communication in the normal procedure in the same sequence.
[0049]
The signal QINFO is used to set the training parameter (INFO0h) at the time of shortening procedure registration, optimal training time, nonlinear distortion correction, etc. according to the contents of the memory 108 registered in advance for each communication partner. Communication is performed by 21 modem 204 (300 bps, full duplex).
[0050]
Next, for the communication procedure 4c for modem training, communication is performed with the training parameter (INFO0h) of the signal QINFO and the optimal training time.
[0051]
The setting of the called MPh communicating in the communication procedure 4d of the modem parameter setting is selected based on the nonlinear distortion correction selection of the QINFO and the SN ratio information calculated in the communication procedure 902 of the modem training.
[0052]
The communication procedure at the time of the shortening procedure is the original procedure only for the communication procedure at the start of the shortening procedure, and this shortens the communication procedure. The communication time is the same as usual.
[0053]
In the present embodiment, as shown in FIG. 5, the configuration of the memory 108 is set so that each modem parameter is registered corresponding to the other party telephone number. However, for example, the other party's telephone number and modem parameters may be registered in correspondence with the speed dial key and redial key of the operation unit 107, so that memory management such as retrieval of the shortened procedure registration memory can be simplified. Good.
[0054]
Next, the procedure for registering various modem parameters in the memory 108 will be described with reference to the flowchart shown in FIG.
[0055]
In steps (hereinafter referred to as ST) 601 to ST604, in procedure 3b during the shortening procedure, a signal INFOh (power suppression value, carrier selection, etc.) including modem parameter (1) based on the line probing signal is transmitted from the called terminal. Temporarily stored in the buffer memory in the modem. In step 3d, a signal MPh (transfer rate, nonlinear distortion correction selection, etc.) including parameter (2) determined based on training is transmitted from the called terminal and temporarily stored in the buffer memory in the modem. The
[0056]
In ST605, in communication procedure 3e, the calling side terminal receives the NSF signal from the called side terminal, and acquires the shortening function flag, the optimal training time, and shoulder gain information.
[0057]
In ST606 to ST610, when the shortening function flag of the NSF signal is “present”, the optimum training time and shoulder gain information are managed in the facsimile apparatus together with the modem parameters stored in the buffer memory in the modem. Transfer to memory and store. As a result, the next communication is executed in the shortened mode. On the contrary, when the shortening function flag is “none”, the switching mode is stored in the memory so that the G3 fax shortening communication procedure or the V34 communication procedure is selected and executed in accordance with the data amount. 108 is registered (ST610). Here, the shoulder gain information is information used for data modulation, and is obtained from the following equations (1) and (2). Note that fc is a carrier frequency and fs is a symbol rate.
[0058]
fc-fs / 2 (1)
fc + fs / 2 (2)
Based on this equation, the frequency used for adjusting the modulation timing according to the line characteristics is calculated. The attenuation amount of each frequency calculated here is obtained, and a value obtained by multiplying these two attenuation amounts is shoulder gain information. The receiving side can detect the attenuation amount of the predetermined frequency based on this information, and can adjust the modulation timing of data from the transmitting side based on the attenuation amount. The shoulder gain information and training time are information used on the receiving side, but are stored on the transmitting side, and each time communication is made from the transmitting side, the receiving side receives this information, so it is easy to deal with the communication partner. Can be managed.
[0059]
This is because, at the start of shortened communication, the receiving side does not know which partner is communicating, and therefore it is simpler to store it on the transmitting side. Further, as an advantage of storing on the transmission side, it is possible to easily store the correspondence with the telephone number using a one-touch key or the like. On the other hand, since the receiving side does not have such a memory configuration, it is necessary to add a new memory, resulting in complication of the apparatus on the receiving side.
[0060]
The NSF signal has a frame configuration shown in FIG. As shown in the figure, 2 bits each indicating the length of the training and the shoulder gain information are assigned to some LSB 4 bits of the NSF signal. These bit patterns set the optimal training length and the correction amount for demodulation. In FIG. 7, 2 bits are assigned and 4 patterns can be set. However, the present invention is not limited to this, and more settings may be made within the range of the number of bits of the NSF signal.
[0061]
It should be noted that the registration of the parameters of the shortening procedure is performed for the one for which one-touch registration has already been performed. When executing a shortening procedure for a terminal having a telephone number input from a numeric keypad or the like, it is necessary to secure the area in a memory so that the telephone number and the modem parameter are stored in pairs. In these cases, registration is performed until the memory is full, and when the memory is full, the number registered in the shortened procedure is overwritten. How to select a certain number is determined by information such as the communication probability and the date of registration of the shortened procedure.
[0062]
In addition, when the caller ID notification service is used, the receiving side can know the other party's telephone number at the start of the shortening procedure. Therefore, the receiving side is configured to store the other party's telephone number, training time, and shoulder gain information. Also good.
[0063]
In the above embodiment, the description has been made on the assumption that the modem is provided with a buffer memory. However, some modems are not provided with a buffer memory. In this case, after acquiring the modem parameters from the partner terminal, it may be controlled to transfer to the management memory inside the facsimile apparatus. Specifically, it is necessary to transfer the INFOh obtained in the procedure 9b, then transfer the MPh obtained in the procedure 9d, transfer the information in the NSF signal obtained in the procedure 9e, and store them in pairs. is there. If the partner does not have a shortening procedure, the received NSF is analyzed and control is performed to delete the parameter once registered from the memory.
[0064]
Next, a procedure for performing communication by deciding whether or not to execute the shortening procedure according to the transmission document amount will be described with reference to the drawings. FIG. 8 is a flowchart for selecting whether to perform the G3 fax shortened communication procedure or the V34 communication procedure. When the amount of originals to be transmitted is small, the entire communication time is rather shortened if the shortening procedure is not executed, so such a selection is made.
[0065]
In ST801 to ST803, after setting the transmission original and inputting the destination, the start button is pressed, the original is once read into the memory for memory transmission, and the data amount of the transmission original is determined.
[0066]
In ST804 to ST805, it is determined whether or not the data amount is a predetermined value or more. If it is equal to or greater than the predetermined value, the higher V.V. Communication is performed according to 34 communication procedures.
[0067]
In ST806 to 807, if the transmission data amount is equal to or smaller than the predetermined value, it is further determined whether or not the transmission destination terminal supports a shortening procedure that is a G3 non-standard procedure. This is determined from the past communication history. If the partner machine supports a non-standard procedure and is equipped with a G3 shortening procedure, communication is performed according to the G3 shortening procedure. When the amount of data is small, V. This is because it takes time to execute the 34 pre-communication procedure. Conversely, if it is not installed, V. Communication is performed in accordance with the 34 communication procedure (ST805).
[0068]
【The invention's effect】
As is apparent from the above description, according to the present invention, V.V. The shortening procedure in 34 procedures can be performed reliably.
[Brief description of the drawings]
FIG. 1 is a block diagram of a data communication apparatus according to an embodiment of the present invention.
FIG. 2 is a functional block diagram of a modem unit of the data communication apparatus according to the embodiment.
FIG. 3 is a communication sequence diagram when registering a shortening procedure of the data communication apparatus according to the embodiment.
FIG. 4 is a communication sequence diagram when executing a shortening procedure of the data communication apparatus according to the embodiment.
FIG. 5 is a schematic diagram of a memory area of the data communication apparatus according to the embodiment.
FIG. 6 is a flowchart at the time of registration of a shortened procedure in the data communication apparatus according to the embodiment
7 is a frame configuration diagram of an NSF signal of the data communication apparatus according to the embodiment. FIG.
FIG. 8 is a flowchart when switching the communication mode of the data communication apparatus according to the embodiment.
FIG. 9 is a communication sequence diagram of a conventional data communication apparatus.
[Explanation of symbols]
104 modem
104a Digital signal processing section
108 memory

Claims (2)

Storage means for storing modem control information for each destination, and when the control information is stored in the storage means, recommendation T. When a shortened communication procedure is transmitted by sending a shortened communication procedure transition notification signal that is a repetitive pattern of “0011” different from the signal pattern of the flag sequence defined by 30 and is not stored, a normal communication procedure call signal And a communication control means for executing a normal communication procedure. Recommendation T. 30. A data transmission method for executing a shortened communication procedure by sending a shortened communication procedure transition notification signal that is a repetitive pattern of “0011” that is different from the signal sequence of the flag sequence defined in 30.

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