JPS63182932A - Data transfer error control system - Google Patents

Abstract

PURPOSE:To easily attain error control of data transmission by adding a data transmission request of other communication equipment to a reply status signal to one communication equipment from the other communication equipment after a data is transferred from the one communication equipment having priority to the other communication equipment. CONSTITUTION:A communication equipment 1 having priority neglects the transmission request of the communication equipment and transfers the transmission request to await a reply status signal from the communication equipment 4. Moreover, the communication equipment 4 applies processing to the transmission request from the communication equipment 1 with priority and sends a reply status signal of the transmission request to the communication equipment 1. In this case, based on the command from the control means, a transmission request is added to the reply status signal. Thus, the communication equipment 1 awaits the data reception from the communication equipment 4 while sending the reply status signal when the transmission request comes from the communication equipment in receiving the end reply status signal.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a data transfer error control system between two communication devices.

[Prior art] Although the transmission of a signal in either direction is +q HE,
Interchange depending on the nature of the terminal equipment! Transmission is 1 in only one direction in f
+ (In the case of a capable half-duplex transmission system, there is a risk of data collisions unless there is some kind of control. For this reason, in the past, when data was transferred between one communication device, data transmission requests were sent at the same time) When an error occurs, a data transfer error control method is adopted in which either one of the communication devices is given priority in the transmission request, or the other communication device is made to issue the transmission request again at the appropriate timing.

[Problems to be solved] - Among the conventional data transfer error control methods described above, the former control method that gives priority to a communication device is a method in which data transmission requests occur continuously from a communication device with priority. In this case, there is a drawback that a data transmission request from the other communication device that does not have priority cannot be accepted forever. In addition, the latter method of sending transmission requests to each other again requires shifting the retransmission timing for each communication device to prevent transmission requests from colliding again, and has the disadvantage that the retransmission timing of transmission requests differs depending on the system. There is.

The present invention was made in view of the problems of the J2 pair.
Once data transfer from one communication device that has priority is completed, even if there are still data transmission requests from this one communication device, data transmission requests from other communication devices can be transferred, and The purpose of the present invention is to provide a data transfer error control method that does not require re-requesting data transmission at different timings.

[Means for Solving Problems] In order to achieve the J-Ashiguchi principle, the data transfer error control method of the present invention transmits data from one communication device that has priority in a data transfer request to another communication device that does not have priority. The system is equipped with a function that allows the data transmission request from the other communication device to be added to the response status signal sent from the other communication device to the one communication device after the transfer.

Furthermore, in AV terms, the present invention is a data transfer method in which two communication devices are connected via a communication line and data is transferred, and when data transmission requests are received from both communication devices at the same time, the data transmission requests collide. is detected, only the transmission data from one communication device with predetermined transmission priority is transferred to the other communication device, and the end response status signal for the final data transferred from one communication device is sent to the other communication device. This is a method for adding the transmission request from the communication device.

[Example] Next, an example of the present invention will be described with reference to one drawing.

FIG. 1 is a system configuration diagram for implementing the present invention.

In this drawing, 1 is one M made by Tsushin, 2 is a line termination device of the communication device I, 3 is the other communication device, and 4 is 2 made by Tsushin.
13 indicates a line termination device, and 5 indicates a communication line.

The signal from one communication device 1 is converted into a signal format suitable for transmission by the line termination device 2, and then sent to the communication line 5.0 The signal sent from the communication line 5 is sent to the line termination device 3. The signal is received by the communication device 4, converted back to the original signal, and then transmitted to the other communication device 4. Further, signals can also be transmitted from the other communication device 4 to one communication device 1 in the reverse order to the above.

Of one communication device 1 or the other communication device 4, or the line termination device 2 or 3 connected to these,
At least one of them has a built-in control means. This control means detects that the data transmission requests from the communication devices 1 and 4 collide, and when they collide, the transmission request from the upper communication device 211 is given priority, and the transmission request from the other communication device 4 is Processing is performed to ignore the request, and after the final data based on the transmission request from one communication device t has been transmitted, the other communication device ignored when there is a conflict in the completion response status for this data. Processing to add the transmission request from 4 is performed.

Next, the operation of the present invention will be explained in detail.

Transmission data from the communication device 211 is converted by the line termination device 212 into a signal system suitable for transmission, and then sent to the communication line 5. The signal from this communication line 5 is transferred to the line termination equipment 2.
13, converts it back into the same signal as the signal from communication device t, and sends it to the other communication device 4. After checking the normality of the received data, the other communication device 714 responds in the following order: communication device 4 → line termination device 213 → communication line 5 → line termination device 2 → communication device 1. Send status to 1. Further, if the received data is abnormal, an abnormal response status signal indicating a transmission error is sent from the other communication device 4 to the one communication device l in the same order.

FIG. 2 is a sequence diagram for explaining the data transfer error control method of the present invention. This diagram shows one communication device 1
This is an explanatory diagram when a transmission request from the communication device 4 and the other communication device 4 occur at the same time.

That is, since the transmission request from the communication device 1 is given priority in advance according to the command from the control means, one communication device 1 ignores the transmission request from the other communication device 4 and transfers the transmission request, Communication device 4 for this transmission request
It enters a state where it waits for a response status signal from. The other communication device 4 processes the transmission request from one communication device 11 with priority, and sends a response status signal of the transmission request to the one communication device 1. - After all the data is transferred from the communication device 1 on the side Y to the communication device 4 on the other side, the other communication device 4 sends the final r response status signal to 1, but at this time, in response to the command from the first stage of control Jf. Based on this, a transmission request is added to the response status signal.

As a result, when one communication device 1 receives the final response status signal -), if there is a transmission request from the other communication device 4, it sends a response status signal to the transmission request to the communication device 4 and performs communication. It is now waiting for data to be received from the manufacturer η4.

Note that it is of course possible to give priority to transmission to a transmission request from the other communication device.

In this manner, the present invention performs control when transmission requests from both communication devices collide.

[Effects of the Invention] As explained above, when a transmission request occurs at the same time in one communication device and the other communication device connected by a communication line, the communication device that has transmission priority is After transmitting data to the other communication device, it has a function that can add a data transmission request from the other communication device to the response status signal sent from the other communication device to the other communication device.
It is possible to easily control errors in data transmission.
This has the effect of making it possible to use communication lines more effectively and speeding up data transfer.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a system implementing the present invention, and FIG. 2 is a sequence diagram for explaining the present invention in detail. 1.4: Communication device 2, 3: Line termination device 5: Communication line

Claims (1)

[Claims] In a data transfer method that connects two communication devices via a communication line and transfers data, if both communication devices request data transmission at the same time, it is detected that the data transmission requests collide. Only transmission data from one communication device that has transmission priority is transferred to the other communication device, and a completion response status signal from the other communication device is sent to the final data based on the transmission request transferred from one communication device. A data transfer error control method characterized by adding the transmission request.