JP2739321B2 - Transmission control method for data communication device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a transmission control method for a data communication device connected to a wireless device and performing data transmission using the wireless device.

[Related Art] In recent years, a wireless facsimile apparatus using a wireless device such as an automobile telephone device as a transmission unit has been provided.

Among such wireless facsimile apparatuses, a car telephone facsimile apparatus is a group 3 facsimile apparatus which can transmit image information not only to each other but also to a group 3 facsimile apparatus connected to a general public telephone line. It has a transmission function equivalent to a facsimile machine.

In addition, even for other wireless facsimile devices,
Many have the same function as the group 3 facsimile machine.

On the other hand, in a wireless facsimile apparatus, depending on the state of the propagation path of the wireless apparatus, the possibility of transmission errors is greater than that of a wired group 3 facsimile apparatus, so the transmission function is set or various transmission controls are performed. A transmission error may also occur in a transmission control procedure signal to be performed.

Therefore, conventionally, to eliminate such transmission errors,
2. Description of the Related Art A radio facsimile apparatus has been put into practical use in which a transmission control procedure signal is exchanged with an error correction code added to the transmission control procedure signal, thereby correcting a data error generated in the transmission control procedure signal.

However, if the type of the error correction code added by the wireless facsimile apparatus is different, the content of the transmission control procedure signal cannot be identified, and as a result, there is a possibility that the inconvenience that image information cannot be transmitted properly may occur. There is.

[Purpose] The present invention has been made in order to solve the problems of the related art, and has as its object to provide a transmission control method of a data communication device capable of appropriately exchanging transmission control procedure signals. And

[Configuration] The present invention relates to a transmission control method for a data communication device connected to a wireless device and performing data transmission using the wireless device, wherein a standard transmission control procedure signal and a plurality of types of error correction codes are respectively received during reception. The added transmission control procedure signal is sequentially transmitted until there is a response from the transmission side, and when there is a response from the transmission side, data transmission is performed thereafter according to the signal type of the transmission control procedure signal that has been returned. It was done.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a mobile telephone facsimile apparatus according to one embodiment of the present invention.

In FIG. 1, a facsimile apparatus 1 having a function of generating / recording image information is connected to a car telephone apparatus 2 via an interface circuit 3 and exchanges transmission / reception signals. Further, the interface circuit 3 switches between the handset 4 and the facsimile machine 1 of the car telephone apparatus 2 and connects to the car telephone apparatus 2.

In the facsimile machine 1, the system control unit 11
The scanner 12 is for performing the overall control processing of the facsimile apparatus 1, the scanner 12 is for reading a transmission original at a predetermined resolution, and the plotter 13 is for recording and outputting an image at a predetermined resolution. It is.

The operation display unit 14 is for operating the facsimile apparatus, and the encoding / decoding unit 15 encodes and compresses the transmission image signal and decodes the reception image information to the original image signal. Yes, the communication control unit 16 is for performing facsimile transmission control procedure processing, and the modem 17 is
It modulates and demodulates digital data. Input / output signals of the modem 17 are exchanged with the mobile telephone device 2 via the interface circuit 3.

These system control unit 11, scanner 12, plotter 1
3. The operation display unit 14, the encoding / decoding unit 15, and the communication control unit 16 exchange necessary data via the system bus 18.

The transmission control procedure signal exchanged by the car telephone facsimile apparatus has the same frame format as the transmission control procedure signal specified for the group 3 facsimile apparatus, as shown in FIG. 2 (a).

That is, a non-standard function frame FNS for transmitting a transmission control procedure signal for setting a non-standard function of the facsimile apparatus 1 and a called terminal for transmitting identification information of a called station (called station). A preamble consisting of an identification frame FCD and a digital identification frame FDI for transmitting a standard transmission control procedure signal, and a flag sequence F repeated a certain number of times to synchronize the binary information frame BF with the receiving side. PA is added.

Each of the non-standard function frame FNS, the called terminal identification frame FCD, and the digital identification frame FDI has a HDLC (high-level data link control) procedure frame format as shown in FIG. 3 (a). Has a compliant configuration.

Note that, depending on the type of the transmission control procedure signal, the non-standard function frame FNS or the non-standard function frame
There may be no non-call terminal identification frame FCD, and the binary information frame BF is the digital identification frame FD.
It may be composed of only I.

This frame format includes two flag sequences F1 and F2 each having a predetermined 8-bit pattern, an address field A having a predetermined 8-bit pattern (global address), a control field C having an 8-bit pattern unique to a facsimile apparatus, and a facsimile. 8 of transmission procedure signal
Facsimile control field FCF in which a bit pattern is arranged, facsimile information field FI in which various information added to the facsimile transmission procedure signal are arranged
F, frame check sequence in which a 16-bit CRC (Cyclic Redundancy Check) code for error detection from address field A to facsimile information field FIF is arranged
The FCS and the flag sequence F3 are sequentially arranged.

In this frame format, a preamble PA and a flag F used to separate frames are used.
Has a bit pattern of “01111110” as shown in FIG. 3 (b).

In the HDLC procedure, the flag sequence F1, F2,
When five data "1" s are consecutive in the transmission data other than F3, the transmitting side performs a so-called "0" insertion process of inserting data "0" between the next bit data and the next bit data. , Transmission data is adjusted so that six or more data “1” do not continue.

On the receiving side, when five consecutive data "1" appear in the received data, "0" deletion processing for deleting data "0" located in the next bit is performed.

Therefore, in the frame data of the transmission control procedure signal to be actually transmitted, the binary information frame BF part is “0”.
After the insertion process, as shown in FIG.
The number of bits is increased.

In this embodiment, two types of error correction codes are used.

One of them is, as shown in FIG. 4B, a block code (BCH code) ECC in which the block length to be corrected is 8 bits corresponding to the bit length of the flag pattern and the code length is 4 bits. It is. The block code ECC has a capability of correcting a 1-bit error occurring in 12-bit data including itself, and when applied to the flag F, the content of the block code ECC is "0010". It becomes a fixed bit pattern.

The second is a Viterbi code which is a kind of convolutional code. This Viterbi code is stored in the first flag F of the preamble PA.
FIG. 4 (c) shows the bit pattern applied to (1). This Viterbi code has a capability of correcting a 2-bit error in continuous 8-bit data.

Here, the transmission control procedure of the group 3 facsimile apparatus is basically performed as shown in FIG.

That is, when the calling side calls the destination, the called side transmits a signal DIS for notifying the calling side of the transmission function of its own terminal. Thus, the calling side recognizes the transmission function of the destination, transmits a signal DCS for notifying the called side of the transmission function to be used in the transmission, and performs modem training at the modem speed at that time. , Transmit the signal TCF.

If the training result at this time is good, the called side responds with the signal CFR, whereby the calling side transmits the image information PIX using the transmission function set at that time, and ends the procedure. Then, a signal EOP is transmitted.

When the called party has successfully received the image information PIX,
In response to the CF, the calling side responds with a signal DCN indicating disconnection of the line, restores the line, and ends the transmission control procedure.

Therefore, in this embodiment, when the called side transmits the signal DIS which is the first transmission control procedure signal, the frame data without the error correction code, the frame data with the block code ECC added, And, sequentially transmit the frame data with the Viterbi code added,
When either of them is recognized by the calling side and the frame data of the transmission signal DCS is received in the signal format at the time of recognition, the subsequent transmission control procedure signals are exchanged in the signal format of the signal DCS. I have.

That is, as shown in FIG. 6, the called side first sets the signal format of the transmission control procedure signal to the standard group 3 mode (process 101), and completes the "0" insertion process described above. Is transmitted (process 102).

Then, it is determined whether or not the signal DCS (DCS frame) has been received during a period from the transmission of the DIS frame to the elapse of a predetermined time (decision 103).

If the result of decision 103 is NO, the signal format of the transmission control procedure signal is
Is set to the error correction mode 1 (process 104).
The transmission data after the "0" insertion processing is divided into 8 bits at a time from the beginning including the preamble PA, and a block code ECC is added to each 8-bit data, and in that state, a signal DIS (DIS frame) is added. Is transmitted (process 105).

As a result of this processing 105, as shown in FIG. 2 (c), the preamble PA has a form in which the flag F and the error correction code ECC are alternately repeated, and the binary information frame BF has eight bits from the beginning. Error correction code EC for each data
This is a mode in which C is added.

Each frame of the binary information frame BF originally has a length of a multiple of 8 bits, but the number of bits may increase due to the “0” insertion processing, and the length may not be a multiple of 8 bits.

Therefore, the last 8-bit data is a remainder obtained by dividing the number of data after the “0” insertion processing by 8 by 8
The data "0" is added by the number of the results obtained by subtracting from the data.

For example, the number of data after the “0” insertion process is 8
When the number is larger than the multiple of 2 by 2, as shown in FIG. 2D, the last two bits of the flag sequence F3 of the digital identification frame FDI are left (that is, the remainder is 2). Therefore, six data “0” are stored in the two bits.
To form the final 8-bit data, and add an error correction code ECC to the 8-bit data.

Then, it is determined whether or not the DCS frame of the same signal format has been received during a period from the transmission of the DIS frame of the signal format of the error correction mode 1 until a predetermined time has elapsed (decision 106).

If the result of determination 106 is NO, the signal format of the transmission control procedure signal is set to error correction mode 2 in which a Viterbi code is added as an error correction code (process 107), and the transmission after the “0” insertion process is completed. A signal DIS (DIS frame) formed by subjecting the data to Viterbi encoding is transmitted (process 108).

Then, it is determined whether a DCS frame of the same signal format has been received during a period from the transmission of the DIS frame of the signal format of the error correction mode 2 to the lapse of a predetermined time (decision 109).

When the result of the determination 109 is NO, it means that the calling side could not properly receive the transmission control procedure signal, so that the transmission control procedure signal was temporarily changed to a standard group 3 mode in order to terminate the transmission control procedure signal. (Step 110), a signal DCN is sent out to restore the line (Step 11).
1) Furthermore, the operator is notified that the image information could not be received.

If the result of any of the determinations 103, 106, and 109 is YES, the process proceeds to the next transmission control procedure in the signal format set at that time (process 112).

When the calling side receives the transmission control procedure signal (step 201), as shown in FIG.
Standard group 3 mode signal format, block code ECC
It is determined which of the signal format of the error correction mode 1 to which the symbol is added and the signal format of the error correction mode 2 to which the Viterbi code is added (decisions 202, 203, 204).

Here, in these determinations 202, 203, and 204, when two flags F are continuous with the data of the preamble PA, it is determined that the signal format is the standard group 3 mode signal, and the flag F is set to the block code ECC12. If a bit pattern is detected, it is determined that the mode is the error correction mode 1, and if a pattern of the Viterbi code corresponding to the flag F is detected, it is determined that the mode is the error correction mode 2.

When the result of the determination 202 is YES, the group 3 mode is set as the signal format, and in that state, the received signal frame is analyzed (process 205) to determine whether or not the signal DIS has been normally received (step 205). Decision 206).

If the result of determination 203 is YES, error correction mode 1 is set as the signal format, and in this state, the received signal frame is analyzed (process 207) to determine whether or not the signal DIS has been normally received. (Decision 206).

When the result of the determination 204 is YES, the error correction mode 2 is set as the signal format, and in that state, the received signal frame is analyzed (process 208) to determine whether the signal DIS has been normally received. (Decision 206).

When the result of the determination 206 is YES, a frame of the signal DCS is formed in the signal format set at that time and transmitted to the called side (process 209), and the process proceeds to the next transmission control procedure (process 210). .

When the result of the determination 204 is NO, and when the determination 2
When the result of step 06 is NO, the process returns to the signal receiving process 201 and waits for the retransmission of the DIS frame. Also, D
If the time expires while waiting for the retransmission of an IS frame,
At that point, the receiving process ends.

Therefore, as shown in FIG. 8 (a), when the called side transmits the DIS frame in the group 3 mode and the calling side transmits the DCS frame, the signal of the group 3 mode is thereafter transmitted. A transmission control procedure signal is exchanged in a format, and when the called side transmits a DIS frame in the error correction mode 1 as shown in FIG.
When the CS frame is transmitted, the transmission control procedure signal is exchanged in the signal format of the error correction mode 1 thereafter, and the called side transmits the DIS frame in the error correction mode 2 as shown in FIG. When a DCS frame is transmitted from the calling side at the time of transmission, the transmission control procedure signal is exchanged in the error correction mode 2 signal format thereafter.

Thereby, the signal format of the transmission control procedure signal is changed to the error correction mode according to the propagation path state at that time, or
The other terminal device is set to a usable error correction mode,
As a result, transmission control procedure signals can be appropriately exchanged.

By the way, in the above-described embodiment, a wireless facsimile apparatus using a car telephone apparatus has been described, but the present invention can be similarly applied to a wireless facsimile apparatus using other wireless apparatuses.

In the above-described embodiment, the bit length of the flag pattern is set as a unit to which the error correction code is added. However, an integer multiple of the bit length of the flag pattern may be set as one unit.

Further, the types of error correction codes are not limited to those in the above-described embodiment, and the types used are not limited to two.

Further, the method of determining the signal format on the calling side is not limited to the above-described embodiment.

[Effects] As described above, according to the present invention, in a transmission control method of a data communication device connected to a wireless device and performing data transmission using the wireless device, a standard transmission control procedure signal and A transmission control procedure signal to which a plurality of types of error correction codes are added is sequentially transmitted until there is a response from the transmission side. Thereafter, the data transmission is executed, and an effect is obtained that the transmission control procedure signal can be appropriately exchanged.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an automobile facsimile apparatus according to one embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of transmission data, and FIG. 3 (a) is a schematic diagram showing an example of a flag pattern. FIG. 4B is a schematic diagram illustrating a frame format, FIG. 4 is a schematic diagram for explaining an error correction code, FIG. 5 is a time chart showing an example of a basic group 3 facsimile transmission control procedure, FIG. 6 is a flowchart showing an example of processing on the called side, FIG. 7 is a flowchart showing an example of processing on the calling side, FIG. 8 (a) is a time chart showing an example of exchange of transmission control procedure signals, and FIG. b) is a time chart showing another example of exchange of transmission control procedure signals;
FIG. 7C is a time chart showing still another example of the exchange of the transmission control procedure signal. 1 ... facsimile device, 2 ... car telephone device, 3 ...
... Interface circuit, 11 ... System control unit, 16 ...
Communication control unit.

Claims (1)

(57) [Claims] 1. A transmission control method for a data communication device connected to a wireless device and performing data transmission using the wireless device, wherein a standard transmission control procedure signal and a plurality of types of error correction codes are added at the time of reception. The transmission control procedure signal is sequentially transmitted until a response is received from the transmission side, and when a response is received from the transmission side, data transmission is subsequently performed according to the signal format of the transmission control procedure signal returned. Transmission control method for a data communication device to perform.