JPH01232870A - Transmission control system for radio facsimile equipment - Google Patents

Abstract

PURPOSE:To attain proper transmission control by sending a standard transmission control procedure signal and a transmission control procedure signal added with an error correction code sequentially till a caller replies and using the transmission control procedure signal of the signal form replied by the caller after that. CONSTITUTION:A facsimile equipment 1 gives/receives a transmission reception signal with an automobile telephone set 2 via an interface circuit 3. In the automobile telephone facsimile equipment, the called party sends the standard transmission control procedure signal and the transmission control procedure signal added with different kinds of error correction codes sequentially till the transmission control procedure signal corresponding to the caller is replied from the caller, and the caller replies the recognized transmission control procedure signal. After that, the transmission control procedure signal of the signal form replied by the caller is used.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a transmission control system for a wireless facsimile apparatus.

[Prior Art] In recent years, wireless facsimile devices that use wireless devices such as car telephone devices as transmission means have been provided.

Among such wireless facsimile devices, the car phone facsimile device is a Group 3 facsimile device so that image information can be transmitted not only between car phone facsimile devices but also with Group 3 facsimile devices connected to general public telephone lines. It has the same transmission function as a facsimile machine.

Furthermore, many other wireless facsimile devices have the same functions as Group 3 facsimile devices.

On the other hand, wireless facsimile devices have a greater possibility of causing transmission errors than wired Group 3 facsimile devices, depending on the state of the propagation path of the wireless device, so it is necessary to set the transmission function and perform various transmission controls. There is also a possibility that a transmission error may occur in the transmission control procedure signal used to carry out the transmission.

Conventionally, in order to eliminate such transmission errors, a transmission control procedure signal is exchanged with an error correction code added to the transmission control procedure signal. Wireless facsimile devices that are capable of correcting errors are in practical use.

However, if the types of error correction codes added by wireless facsimile devices are different, the content of the transmission control procedure signal cannot be identified, and as a result, there is a risk that image information cannot be transmitted properly. There is.

[Purpose] The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a transmission control method for a wireless facsimile device that enables appropriate exchange of transmission control procedure signals. shall be.

[Configuration] To achieve this objective, the present invention provides that a called party receives a standard transmission control procedure signal as an initial transmission control procedure signal until a corresponding transmission control procedure signal is responded from the calling party. , and transmission control procedure signals to which different types of error correction codes are added are sequentially transmitted, and the calling side responds with a corresponding transmission control procedure signal in the signal format of the transmission control procedure signal that it can recognize. The method uses a transmission control procedure signal in the signal format responded to by the calling party.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a car telephone facsimile device according to an embodiment of the present invention.

In the figure, a facsimile device 1 having a function of generating/recording image information is connected to a car telephone device 2 via an interface circuit 3, and exchanges transmission and reception signals. Further, the interface circuit 3 is connected to the car telephone device 2.
The handset 4 and facsimile device 1 are switched and connected to the car telephone device 2.

In the facsimile family M1, the system control unit 11:
A scanner 12 is used to perform overall control processing of the facsimile machine 1, a scanner 12 is used to read a transmitted document at a predetermined resolution, and a plotter 13 is used to record and output an image at a predetermined resolution. It is.

The operation display section 14 is for operating this facsimile machine, and the encoding/decoding section 15 is for encoding and compressing the transmitted image signal and decoding the received image information into the original image signal. Yes, the communication control unit 16 is for performing facsimile transmission control procedure processing, and is for controlling the modem 1.
7 modulates and demodulates digital data. Input/output signals of the modem 17 are exchanged with the car telephone device 2 via the interface circuit 3.

These system control section 11, scanner 12, plotter 13, operation display section 14, encoding/decoding section 15, and
The communication control units 16 exchange necessary data with each other via the system bus 18.

The transmission control procedure signals exchanged by this car telephone facsimile device are group 3 as shown in FIG. 2(a).
It has the same frame format as the transmission control procedure signal specified for facsimile equipment.

That is, a non-standard function frame FNS for transmitting a transmission control procedure signal for setting a non-standard function of the facsimile device 1, and a called terminal for transmitting identification information of a called station (called station). It consists of an identification frame FCD and a digital identification frame FDI for transmitting standard transmission control procedure signals, into a binary information frame BF,
In order to synchronize the receiving side, a preamble PA made by repeating the flag sequence F a certain number of times is added.

These non-standard function frame FNS, called terminal identification frame FCD, and digital identification frame FDI are:
As shown in FIG. 3(a), each has a configuration that conforms to the frame format of the HDLC (High Level Data Link Control) procedure.

Note that depending on the type of transmission control procedure signal, the binary information frame BF may not have a non-standard function frame FNS or a called terminal identification frame FCD.
Furthermore, the binary information frame BF may be composed only of the digital identification frame FDI.

This frame format consists of two flag sequences Fl and F2 consisting of a predetermined 8-bit pattern, an address field A consisting of a predetermined 8-bit pattern (global address), a control field C consisting of an 8-bit pattern specific to the facsimile machine, and a control field C consisting of an 8-bit pattern specific to the facsimile machine. A facsimile control field FCF in which the 8-bit pattern of the transmission procedure signal is arranged, a facsimile information field PIF in which various information added to the facsimile transmission procedure signal is arranged, and an error detection field from the address field A to the facsimile information field PIF. 16 bit C for
It is formed by sequentially evaluating a frame check sequence FC3 in which an RC (cyclic redundancy check) code is arranged and a flag sequence F3.

In addition, in this frame format, the preamble PA and the flag F used to separate frames are:
As shown in FIG. 3(b), it has a bit pattern of rolllllloJ.

1 (In the DLC procedure, the flag sequence F is set so that the receiving side can reliably identify the bit pattern of this flag F.
l, F2. When there are 5 consecutive data "1"s in the transmission data other than F3, the transmitting side performs so-called rQJ insertion processing to insert data "0" between the next bit data. Transmission data is adjusted so that more than two data "1"s do not occur in a row.

Furthermore, on the receiving side, when five consecutive data "1"s are added to the received data, rQJ region processing is performed to delete data rQJ located at the next bit.

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. 2(b),
The number of bits increases.

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

One of them, as shown in FIG. 4(b), is a block code (B
CH code)ECC. This block code εCC is
It has the ability to correct a 1-bit error that occurs in 12-bit data including itself, and when applied to flag F, the contents of the block code ECC are rooloJ
This results in a certain bit pattern.

The second is a Viterbi code, which is a type of convolutional code, and this Viterbi code is used as the first flag F of the preamble PA.
The bit pattern when applied to is shown in FIG. 4(C). This Viterbi code has the ability to correct 2-bit errors 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 sends a signal DIS to notify the calling side of the transmission function of its own terminal. As a result, the calling side recognizes the transmission function of the destination, sends a signal DC3 to notify the called side of the transmission function to be used for the transmission, and performs modem training at the modem speed at that time. , transmits the signal TCP.

If the training result at this time is good, the called side responds with the signal CFR, and the calling side uses the transmission function set at that time to transmit the image information PIX and completes the procedure. sends a hail signal EOP to

When the called side has successfully received the image information PIX, it responds with a signal MCF, which causes the calling side to.

In response to the signal DCN to disconnect the line,
The line is restored and the transmission control procedure is terminated.

Therefore, in this embodiment, when the called side transmits the signal DIS which is the first transmission control procedure signal, frame data with no error correction code added, frame data with a block code ECC added, Then, the frame data with the Viterbi code added are transmitted sequentially, and when one of them is recognized by the calling side and a low signal DO8 frame data is received in the signal format at the time of recognition, subsequent transmission control is performed. The procedure signal is exchanged in the signal format of signal DC3.

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 (101), and then sets the signal format of the transmission control procedure signal to the standard group 3 mode (101), and then sets the signal format of the transmission control procedure signal to the standard group 3 mode. A signal DIS (DIS frame) is transmitted (process 102).

Then, it is checked whether the signal DC5 (DCS frame) could be received within a certain period of time after transmitting the DIS frame (determination 103).

When the result of judgment 103 is NO, the signal format of the transmission control procedure signal is changed to block code F as an error correction code.
Process to set error correction mode 1 to add CC 104
), the transmission data that has undergone “0” insertion processing,
The data is divided into 8 bits from the beginning including the preamble PA, and a block code E is applied to each 8-bit data.
A CC is added, and a signal DIS (DIS frame) is transmitted in that state (process 105).

As a result of this process 105, as shown in FIG.
are repeated alternately, and the binary information frame BF has an error correction code FCC added to every 8-bit data from the beginning.

Furthermore, although each frame of the binary information frame BF originally has a length that is a multiple of 8 bits, the number of bits increases due to "0" insertion processing, and the length may not be a multiple of 8 bits.

Therefore, the final 8-bit data is constructed by adding data "0" equal to the number of times the remainder is subtracted from 8 when the number of data after rQJ insertion processing is divided by 8.

For example, when the number of data after "0" insertion processing is 2 larger than the multiple of 8,
), the last two bits of the flag sequence F3 of the digital identification frame FDI are left over (ie, the remainder is 2). Therefore, there are 6 data “0” in those 2 bits.
is added to form the final 8-bit data, and an error correction code FCC is added to this 8-bit data.

Then, it is checked whether a DCS frame of the same signal format could be received within a certain period of time after transmitting the DIS frame of the error correction mode 1 signal format (determination 106).

When the result of the judgment 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.
'' A signal DIS (DIS frame) formed by subjecting the transmission data that has undergone insertion processing to Viterbi encoding processing is transmitted (process 108).

Then, it is checked whether a DCS frame of the same signal format could be received within a certain period of time after transmitting the DIS frame of the error correction mode 2 signal format (determination 109).

When the result of judgment 109 is No, it means that the calling party has not been able to properly receive the transmission control procedure signal. Therefore, in order to terminate the transmission control procedure, the signal format of the transmission control procedure signal is changed to the standard group 3 signal format. After returning to mode (
A process 110), a process 111) in which the signal DCN is sent to restore the line, and a message indicating that the image information could not be received is displayed to the operator.

Also, when the result of any of the judgments 103, 106, and 109 is YES, the signal format set at that time is used.

The process moves to the next transmission control procedure (process 112).

Further, as shown in FIG. 7, when the calling side receives a transmission control procedure signal (process 201), the signal frame is
Standard group 3 mode signal format, block code EC
A signal format of error correction mode 1 with C added, and
Determine which of the error correction mode 2 signal formats to which the Viterbi code is added (determinations 202 and 203).
, 204).

Here, in these judgments 202, 203, and 204, if two flags F are consecutive in the preamble PA data, it is judged that the signal format is the standard group 3 mode, and flag F and If a 12-bit pattern of block code ECC is detected, it is determined that error correction mode 1 is in effect, and if a Viterbi code pattern corresponding to flag F is detected, it is determined to be error correction mode 2.

When the result of judgment 202 is YES, group 3 mode is set as the signal format, and in that state, the received signal frame is analyzed (process 205), and it is determined whether the signal DIS was successfully received ( Judgment 206).

When the result of judgment 203 is YES, error correction mode 1 is set as the signal format, and in that state, the received signal frame is analyzed (process 207) to determine whether the signal DIS was successfully received. (Judgment 206).

When the result of judgment 204 is YES, 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 was successfully received. (Judgment 206).

When the result of judgment 206 is YES, a frame of signal DO8 is formed in the signal format set at that time and transmitted to the called party (process 209), and the process moves to the next transmission control procedure (process 210).

Note that when the result of the first judgment 204 is No, and when the result of the judgment 206 is No, the process returns to the signal reception process 201 and waits for the DIS frame to be retransmitted. Furthermore, if a time-out occurs while waiting for retransmission of a DIS frame, the receiving process is terminated at that point.

Therefore, as shown in FIG. 8(a), if the called side sends a DIS frame in group 3 mode and the calling side sends a DCS frame, from then on, the signal is in group 3 mode. Transmission control procedure signals are exchanged in the following format, and as shown in FIG. 2(b), when the called side sends a DIS frame in error correction mode 1, when the calling side sends a DCS frame, From then on, transmission control procedure signals are exchanged in the signal format of error correction mode 1, and as shown in Figure (c), when the called side transmits a DIS frame in error correction mode 2, the When a frame is transmitted, transmission control procedure signals are thereafter exchanged in the error correction mode 2 signal format.

As a result, the signal format of the transmission control procedure signal is set to an error correction mode according to the propagation path state at that time, or to an error correction mode that can be used by the other party's terminal equipment, and as a result, the transmission control procedure signal is Can exchange signals.

Incidentally, in the above embodiment, a wireless facsimile device using a car telephone device has been described, but the present invention can be similarly applied to a wireless facsimile device using other wireless devices.

Further, in the above-described embodiment, the bit length of the flag pattern is used as a unit for adding an error correction code, but it is also possible to set an integer multiple of the bit length of the flag pattern as one unit.

Furthermore, the types of error correction codes are not limited to those of the embodiments described above, and the types used are not limited to two.

Furthermore, the method for determining the signal format on the calling side is not limited to the method described in the embodiment described above.

[Effects] As explained above, according to the present invention, the called side uses the standard transmission control procedure signal as the first transmission control procedure signal until the calling side responds with the corresponding transmission control procedure signal. , and transmission control procedure signals to which different types of error correction codes are added are sequentially transmitted, and the calling side responds with a corresponding transmission control procedure signal in the signal format of the transmission control procedure signal that it can recognize. Since the method uses the transmission control procedure signal in the signal format responded to by the calling side, it has the advantage that the transmission control procedure signal can be exchanged appropriately.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an automobile facsimile device according to an embodiment of the present invention, FIG. 2 is a schematic diagram showing an example of transmitted data, and FIG. 3(a) is a schematic diagram showing an example of a flag pattern. (b) is a schematic diagram illustrating the frame format, FIG. 4 is a schematic diagram for explaining the error correction code, 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, b) is a time chart showing another example of transmission control procedure signal exchange;
FIG. 4(c) is a time chart showing still another example of the exchange of transmission control procedure signals. 1...Facsimile device, 2...Car phone device,
3... Interface circuit, 11... System control section, 16... Communication control section. Figure 5 Figure 6 Figure 8 (a) (b)

Claims (1)

[Claims] In a transmission control system for a wireless facsimile device that uses a wireless device as a transmission means, there is an error correction addition means for adding multiple types of error correction codes to a transmission control procedure signal, and an error correction method for adding received transmission control procedure signals to the received transmission control procedure signal. Equipped with an error correction means that corrects errors by referring to the code, the called side transmits a standard transmission control procedure signal and a transmission with each type of error correction code added as the first response transmission control procedure signal. Control procedure signals are transmitted sequentially until the calling party responds with a corresponding transmission control procedure signal, and the calling party transmits the first transmission control procedure signal received as a standard transmission control procedure signal or one of the standard transmission control procedure signals. It determines whether the transmission control procedure signal has an error correction code added and responds with a transmission control procedure signal in a signal format based on the determination result, and thereafter does not use the transmission control procedure signal in that signal format. , on the other hand, a transmission control method for a wireless facsimile apparatus, characterized in that the called side thereafter uses the signal format of the transmission control procedure signal that is first responded to from the calling side.