JPS61200765A - Retransmission system in facsimile communication - Google Patents

Abstract

PURPOSE:To obtain a retransmission system more suitable for communication errors of each communication phase by selecting a time when a call is restored or disconnected until the retransmission signal is started as at least two kinds of different times. CONSTITUTION:When a line is restored or disconnected due to communication fault, a CPU 17 sends a replay of communication fault to a CPU 11 via a common share memory 16. When the communication fault takes place 3 times, the CPU 11 stops transmission and allows a printer to output an original unarrival message. When the communication fault is less than 3 times and the reply of the end of phase A from the CPU 17 is received, a value corresponding to 1min to a timer 14, and when not received, data corresponding to 5min is written on the timer 14 to start the timer. When the timer 14 counts up, an interruption signal is sent to the CPU 11 to send a call request to the CPU 17 via the memory 16 to execute again the communication.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a facsimile communication system, and in particular has a function of storing image information of a document, and if an abnormality occurs during one communication, the call is restored or The present invention relates to a retransmission method for a facsimile machine that has a function of automatically retransmitting when disconnected.

[Conventional technology]

Conventionally, with facsimile machines that do not have a function to store document image information, if a communication error occurs for some reason and the call is restored or disconnected, the operator has to scan again from the document where the communication error occurred. I had to.

Furthermore, there is a facsimile machine that has a function of storing image information of a document and then transmitting it, in case a communication error occurs and the call is restored or disconnected.

It was not necessary to scan again as described above5, so it was possible to automatically retransmit the call after a certain period of time after the call was disconnected. The said retransmission.

It is possible to repeat this process infinitely until all the image information of the original is sent to the other device, but if the other device is malfunctioning or there is no mutual communication, it may not be possible to send the image even if it takes a long time, usually twice. Until then.

[Problems to be Solved by the Invention] However, when considering the causes of recovery or disconnection in the call setting and line establishment phases and the subsequent phases, the former cause is due to While the main cause of the failure is an abnormality in the other party's equipment, the latter cause is mainly due to data loss due to deterioration in the quality of the 9 lines.In general, the average recovery time from the above causes depends on the call setup. and is considerably larger during the line establishment phase than during the subsequent 7A's. Therefore, the limited number of retransmissions,
Retransmission start time Under certain conditions, there is a problem that connection cannot be established due to a retransmission start time that is too small in the call setup and line establishment phases, or that the wait time for retransmission is wasted in the phase after line establishment. there were.

[Means for solving problems]

The retransmission method in facsimile communication according to the present invention is a facsimile device having a function of automatically retransmitting a call when the call is restored or disconnected due to one communication error during transmission. The present invention is characterized in that the time from the time when the call is restored or disconnected to the time when the retransmission is started is set to at least two different times depending on the phase.

[Effect]

According to such a configuration, the retransmission start time ( retransmission (from the time the call is restored or disconnected to the time the retransmission is started).

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 2 shows the results obtained by applying the retransmission method of the present invention to nine CCITT (International Telegraph and Telephone Consultative Committee: Com1t; Con5ult).
atifInternational T@legra
This is a block diagram showing the communication control unit and retransmission control unit of the AM standard 7 Aximi IJ device recommended by phiqua et Telaphonique).

In FIG. 2, 11 is a general-purpose 8 that controls the retransmission control section.
The bit CPU 12 is a read-only memory (hereinafter referred to as "read-only memory") in which the program of the CPU 11 is stored.

13 is a random access memory (hereinafter referred to as ROM) for the working strain of the CPU 11.

(abbreviated as RAIvl), 14 is a timer LSI having three channels of timers on one chip.

15 is a general-purpose parallel input/output LSI, which will be described later as shared memory 1.
6 and handshake with the CPU 17 of the communication control section described later. 16 is the CPU 11 of the retransmission control unit
This is a shared memory between the CPo 17 and the communication control unit CPo 17.

The sharing of information between the retransmission control unit and the communication control unit is performed via this shared memory 16.

17 is a general-purpose 8-bit CPU that controls the communication control unit;
18 is a ROM in which the program of the CPU 17 is stored, and 19 is a RAM for working storage of the CPU 17.

20 is a general-purpose parallel input/output LSI used for controlling the shared memory 16 and handshaking with the CPU 11 of the retransmission control section.

Reference numeral 21 denotes a transmitting/receiving buffer used for exchanging image signal data with an external magnetic disk device.

This exchange of image signal data is performed by direct memory access (hereinafter abbreviated as DMA) transfer in units of 10 bytes. DMA transfer and DM of image signal data between the communication protocol control unit 23 and the transmission/reception buffer 21, which will be described later.
A transfer is also performed by the DMA transfer control LSI 22. 23 is a communication protocol control unit.

Framing of binary instructions specified in CCITT Recommendation T.30, 7-frame checking sequence (hereinafter referred to as
(abbreviated as Fe2) error detection and modem control.

Performs image signal data transmission and reception. 24 is the timer 1
It is the same 3 channel timer as 4, and this is mainly CED.
(Ca1led 5tation 1dentifi
cation: Identification of called station) / CN
Transmission of G (Calling tone) signal, T, used as a timer in 30 binary hands. Reference numeral 25 denotes a disk control unit and a disk device, in which image information of the scanned and transmitted original is stored.

Figure 3 shows the time sequence of a facsimile call according to CCI TT Recommendation T.30, and the facsimile control procedure basically consists of five phases (phases A to
It is divided into Phase E).

Phase A is the generation of a call. 9 Call generation is realized manually or automatically.

Phase B is the pre-message procedure, and the Brimessage handicraft identifies abilities and issues the two selected conditions.

and confirm the terms and conditions of acceptance.

Phase CI is an in-message procedure, which is executed simultaneously with the message transmission described later, and is a complete signal transmission for the in-message procedure.

For example, it controls message synchronization, error detection, correction, and line monitoring.

Phase C2 is the message procedure, and the message transmission procedure is defined by the appropriate recommendation for the device.

In Phase D\'i post-message procedure, the post-message procedure is an end-of-message (EOM) procedure.
) signal transmission, confirmation signal transmission, multi-pass signal transmission, and facsimile IJ procedure completion signal transmission.

Phase E is call recovery, which is performed manually or automatically.

Next, the operation of each part during document transmission will be described. When the retransmission control unit receives a call request command from the outside, it transfers the call request command to the communication control unit via the shared memory 16. In response to this, the CPU 17 transmits a ringer using the timer 24 of the communication protocol control section 23.

Send CNG signal and perform binary procedure. Opponent G
I [I standard facsimile machine to DIS (Digit
alidentification signal:
7” CPU 1 when receiving the Innotal identification signal) signal
7 is the CPU 11 of the retransmission control unit via the shared memory 16
A response indicating the completion of phase A is sent back to the command of the call request.

In response to this, the retransmission control unit CPU 11 sends a command for requesting to read y' isk to the CPU 17 via the shared memory 16. The communication control unit CPU 17 receives TCP (T
raining check: CFR (Confirmation check) is applied to the training check signal.
Upon receiving the to receive (receipt confirmation) signal, a disk read response is returned via the shared memory 16. The CPU 11 receives this and sends a read signal to the disk control unit 25, and the disk control unit 25 sends 10 bytes of image signal data to the transmit/receive buffer 2 by DMA transfer.
Write to 1.

The CPU 17 receives this image signal data, activates the DMA control LSI 22, sends it to the communication protocol control section 23, and sends the image signal to the other party's device. The communication of the image signal is transmitted as described above by repeating the command and response to the disk read request.

When all image signals are transmitted and communication is completed normally, CP
The U 17 sends a communication end response to the CPU 11 via the shared memory 16.

Next, we will describe the operation when one communication error occurs during communication and two lines are restored or disconnected.

If a communication error occurs and the two lines are restored or disconnected, C
The PU 17 sends a communication error response to the CPU 11 via the shared memory 16. If this communication abnormality occurs for the third time, the CPU 11 will stop sending this document.

Make Grinter output an undelivered message.

When the communication abnormality occurs less than three times, if the communication control unit's CP
If the phase A end response is received from U17,
Write data worth one minute into the timer 14 and start it. If the response indicating the end of phase A has not been received, data worth 5 minutes is written to the timer 14 and activated. Timer 14 counts 7! Then C
Send an interrupt signal to PU l1. The CPU 11 receives this interrupt signal, and similarly to the above, the CPU 11 of the communication control section
17 via the shared memory 16, and communication is executed again in the same manner as described above. Data stored in the disk that has been sent for one page is not sent, but is resent from the first page that could not be sent due to a previous communication error.

Next, the transfer of commands and responses via the shared memory 16 will be described. The shared memory 16 is connected to the internal data bus of either the CPU 11 or the CPU 17 by a shared memory control signal. Also, L for parallel input/output
Information about the end of writing and the end of reading is sent to the other CPU K by the SI 15 and SI 20 shake signals. When transferring commands from CPU 11 to CPU 7, confirm that CPU 17 has finished reading.

The shared memory is connected to the internal data bus of the CPU 11 using a shared memory control signal on the CPU 11 side, data is written, and then a write completion signal is sent to CPo 17 K.

In response to this, the CPU 17 uses a shared memory control signal on the CPU 17 side to connect the shared memory to the internal data bus of the CPU 17, reads the data, and then sends a reading completion signal to the CPU 11. In this way, commands are transferred from the CPU 11 to the CPU 17.

The response is also transferred from CPU 17 to CPU 11 in the same manner as described above.

To make this retransmission scheme more clear, please refer to Figure 1.

The algorithm of the retransmission control section and the communication control section is shown in a flowchart. Step 1 is the state of starting transmission. At the beginning of step 2, the communication control unit receives a call request command, and thereafter
Implement CITT Recommendation T, 30 Binary-Flat.

If all documents were successfully sent in step 3,
If the transmission is completed in step 9, and if there is a communication error, the retransmission control unit returns the number of communication errors to 3 in step 4.
Determine if it is less than 3 times.

If the number of times reached three times, in step 8 a document undelivered message indicating to the operator that all the documents could not be sent to the partner device is printed, and in step 9 the operation is ended.

If the number of communication errors in step 4 is less than 3, fp
If so, in step 5 it is determined whether a response indicating the end of phase A has been received from the communication control unit. If you have received the above response,
Step 6 starts a 1 minute timer. On the other hand, if you have not received the said response.

Step 7 starts a 5 minute timer. Once these started timers count up.

In step 2, the communication control unit receives a call request again from the retransmission control unit and starts transmission.

〔Effect of the invention〕

As explained above, in the present invention, the time from when the call is restored or disconnected due to 1 communication error to the time when retransmission is started, that is, the retransmission start time, is the communication phase in which the call is restored or disconnected due to 1 communication error. It is said that by setting different values for the 7 aids of call setup and line establishment, or for the subsequent phases, a retransmission method more suitable for communication abnormalities for each communication need can be obtained. has advantages.

[Brief explanation of drawings]

Fig. 1 is a flowchart showing an example of the algorithm of the retransmission method according to the present invention, and Fig. 2 is a flow chart showing an example of the algorithm of the retransmission method according to the present invention. FIG. 3 is a block diagram showing the configuration of one embodiment, and is a diagram showing a time sequence of a facsimile call according to CCITT Recommendation T.30. 1... Sending start state, 2... Original sending state, 3...
- Judgment of communication abnormality, 4... Judgment of the number of times communication abnormality occurred. 5...Judgment of communication phase, 6...Waiting for 1-minute timer to count up, 7...Waiting for 5-minute timer to count up, 8...Printing of original undelivered message, 9...Sending End status.

Claims (1)

[Claims] 1. In a facsimile machine that has a function of automatically retransmitting when a call is restored or disconnected due to a communication error during transmission, the call is restored or disconnected according to the communication phase in which the call was restored or disconnected due to the communication error. A retransmission method for facsimile communication, characterized in that the time from the time of disconnection to the time of starting the retransmission is set to at least two different times.