JPH0832645A - Data communication controller and checking method for its data transfer - Google Patents

Abstract

PURPOSE:To provide the data communication controller of high versatility by arbitrarily setting control information such as text start information and text end information, which are added to data and constitute a block. CONSTITUTION:An application program 6 is stored in a memory controlled by CPU 4, and it executes a processing for setting various pieces of communication parameter information for a communication control processor 5 before the execution of communication start. The communication control processor 5 transmits data in a block unit to an opposite station 2 based on text data supplied from CPU 4 and communication parameter information, receives data transmitted from the opposite station 2 and communication-controls data supplied to CPU 4. Furthermore, the communication control processor 5 stores communication parameter information supplied from CPU 4, generates data of a transmission block system, to which control information included in communication parameter information is added, and transmits/receives data in the block unit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data communication controller used in a data communication system between computers.

[0002]

2. Description of the Related Art Conventionally, for example, in a distributed data communication system, a data communication control device is provided in each station connected by a data communication line, and a predetermined transmission control procedure (communication procedure) is provided by this data communication control device. Is running. A station is a device that transmits and receives data, and is usually a computer or terminal device.

The transmission control procedure is executed by the communication control processor provided in the data communication control device. There are various types of transmission control procedures, and for example, the basic procedure of JIS standard (basic data transmission control procedure) is well known. This basic procedure includes a communication phase (phase) of establishing a data link (link establishment), transmitting / receiving data (data transfer), closing a communication line or disconnecting a data line (link disconnection).

By the way, in a transmission control procedure such as a basic procedure, information to be transmitted (called an information message) is processed in block units. The transmission block format consists of text data, which is the body of information to be transmitted and received, transmission control characters (hereinafter referred to as control information), and block check characters (BCC). The control information is set by, for example, JIS 7-bit code, and the text start information (STX) and the text end information (ETX).
Etc. The BCC is a check code for detecting a data error in a text block (block containing control information), and is, for example, a CRC (Cyclic Redund).
ancy code).

In addition to STX and ETX, the control information includes transmission end (EOT), inquiry (ENQ), and affirmative response (A).
CK), negative acknowledgment (NAK), etc. Each station executes a transmission control procedure based on these control information. In the transmission control procedure, there are communication parameter information such as various timer values and retry values, which are set in advance by an instruction from the outside (user). For example, in the data transfer phase, when a negative response (NAK) is transmitted from the partner station, the data transfer is retried the number of times corresponding to the set retry value.

[0006]

In the conventional data communication system, start information (STX) and end information (ET) are added to text data by a transmission control procedure such as a basic procedure.
Transmission / reception is performed in block units to which control information such as X) is added. This start information (STX) and end information (E
TX) is fixedly set in advance by a standard such as JIS 7-bit code. Therefore, the data communication between the stations is possible only when the data communication control device supporting the control information by the code according to the standard or the predetermined specific code is used. In other words, the conventional data communication control device does not have general versatility and cannot communicate with a station using the data communication control device supporting the control information of different codes.

Further, in the process of checking the transmitted / received data, only the text block check by BCC is executed. For this reason, even when a text block having an abnormality in the text data part excluding the start information (STX) and the end information (ETX) is received, the check process by the BCC is normal, and therefore an affirmative response may be transmitted. In this case, the station that has received the positive response has a risk of discarding the transmitted information. Normally, when a negative response is received, the information sent is not discarded, so
It is easy to recover and analyze information.

The first object of the present invention is to provide a highly versatile data communication control device by making it possible to arbitrarily set control information such as text start information and text end information which are added to data to form a block. To provide. Second
Another object of the present invention is to provide a data communication control device capable of reliably checking the entire data in block units to be transmitted and received by providing a check function of the control information added to the data.

[0009]

A first object of the present invention is to provide a data communication control device comprising a transmitting means and a receiving means for transmitting / receiving block-unit data to / from a partner station in accordance with a predetermined transmission control procedure. Control information setting means for arbitrarily setting control information including start information and end information from outside, a transmitting means for transmitting data in block units, and a receiving means for receiving data in block units transmitted from the partner station. It is a device.

A second aspect of the present invention is a data communication control device for transmitting / receiving block-unit data to / from a partner station in accordance with a predetermined transmission control procedure, from outside the control information including start information and end information of the data. A control information setting means, a transmission means for transmitting data in block units, and a receiving means for executing a check process based on the added control information when receiving data in block units transmitted from the partner station. It is an equipped device.

[0011]

According to the first aspect of the present invention, the control information setting means arbitrarily sets the control information including the start information and the end information of the data by the instruction of the user when transmitting the data in block units to the partner station. . The transmitting means transmits block-unit data to which the set control information is added to the partner station.
As a result, it is possible to transmit block-unit data according to the control information supported by the partner station.

In the second aspect of the present invention, when transmitting the data in block units to the partner station, the control information setting means arbitrarily sets the control information including the start information and the end information of the data according to an instruction from the user or the like. . The transmitting means transmits block-unit data to which the set control information is added to the partner station. On the other hand, the receiving means receives the data in block units transmitted from the partner station, and executes the checking process based on the control information added to the received data. As a result, it is possible to transmit data in block units according to the control information supported by the partner station, and it is possible to check the control information for an abnormality, so that it is possible to check the entire data.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a data communication system according to the embodiment, FIG. 2 is a conceptual diagram for explaining communication parameter information and data contents according to the embodiment, and FIGS.
Is a flow chart for explaining the operation of the embodiment, and FIG. 5 is a diagram for explaining the transmission control procedure of the embodiment.

In this system, as shown in FIG. 1, the data communication control device 1 of its own station and the partner station are connected via a communication line 3 to send and receive data. Each station is a computer or a terminal device. In this embodiment, for convenience, only data transfer between two stations is assumed. Further, in the present embodiment, it is assumed that the partner station is provided with the same data communication control device 1 as the own station.

The data communication control device 1 is roughly classified into a processor (CPU) that executes an application program.
4 and a communication control processor (CCP) 5. The application program is software stored in the memory 6 controlled by the CPU 4 and for performing processing of setting various communication parameter information to the communication control processor 5 before execution of communication start.

The communication control processor 5 transmits block-unit data to the partner station based on the text data and communication parameter information supplied from the CPU 4,
It also executes data communication control for receiving the data transmitted from the partner station and supplying it to the CPU 4. As will be described later, the communication control processor 5 stores the communication parameter information supplied from the CPU 4, generates the data in the transmission block format to which the control information included in the communication parameter information is added, and performs the predetermined transmission. Data is transmitted and received in block units according to a control procedure (basic procedure, etc.). In data transmission / reception, modem 7 performs modulation / demodulation processing.

Next, the operation of the embodiment will be described. (Transmission Mode) First, in the embodiment, step S1 in FIG.
As shown in, the CPU 4 executes the setting process of the communication parameter information by the application program.
Specifically, the CPU 4 outputs a command including a parameter setting control block according to an instruction from the outside (user). That is, for example, when the user inputs a parameter setting instruction from the input device (keyboard or the like) of the own station, C
PU4 starts the setting process and outputs a command. As shown in FIG. 2A, this command is a block size indicating the size of the parameter information block (see FIG. 2B), identification information indicating that this block is a parameter setting control block, and parameter information. It consists of a block address.

As shown in FIG. 2B, the parameter information block includes start information (ST) and end information (ET) which are control information (transmission control character) indicating the start and end of text data, and each byte. It consists of a number and other parameter information. The other parameter information is, for example, a communication speed or a retry value.

The communication control processor 5 stores the parameter information block supplied by the CPU 4 in the internal memory and starts the data transmission control (step S2). Here, in a transmission control procedure such as a basic procedure, a data link establishment phase (link establishment processing) for establishing a logical transmission / reception path with a partner station is executed (step S3). As a concrete procedure, as shown in FIG. 5A, the communication control processor 5 of the own station
Send a link connection request (ENQ). When an acknowledgment (ACK) is received from the partner station, a link establishment notification is given and the link is established.

When the link is established, the communication control processor 5 starts the data transmission process (YE in step S4).
S). The communication control processor 5 starts the start information (ST) and the end information (ET) from the set parameter information block.
Is read from the internal memory to generate transmission data in the transmission block format (step S5). As shown in FIG. 2C, the transmission block format data includes text data (user data), control information of start information (ST) and end information (ET), and block check character (BCC).
The unit is a text block to which is added. In the information message transmitted, as shown in FIG. 2D, a text block is composed of a plurality of blocks and a header. Here, the end information (E
T) is information indicating the end of block (ETB in JIS)
The end information (ET) of the last text block is information indicating the end of the text (ETX in JIS).

As shown in FIG. 5A, the communication control processor 5 transmits the text block generated in the data transmission phase (data transfer) to the partner station (step S6). When an acknowledgment (ACK) indicating that data has been normally received is transmitted from the partner station, the communication control processor 5 transmits until the end of the text block (YES in step S7, NO in step S8).

Here, when the negative response (NAK) is transmitted from the partner station, the communication control processor 5 executes a predetermined NAK process (NO in step S7, S9). For example, data transmission is retried a number of times according to the retry value of the set parameter information block, and an acknowledgment (ACK) is sent.
If is not obtained, a predetermined transmission error process is executed.

After transmitting up to the last text block, the communication control processor 5 shifts to a phase of terminating the communication line or disconnecting the data line (link disconnection) as shown in FIG. 5 (A). That is, the communication control processor 5 transmits the control information indicating the end of transmission (EOT) to the partner station (YES in step S8). (Reception mode) On the other hand, the reception mode (step S1 of FIG. 4)
In 0), as shown in FIG. 5B, for example, when a link is established from the partner station by a link connection request (ENQ), the communication control processor 5 transmits a reception request to the partner station. Partner station requested data (text block)
Is transmitted (data transfer phase).

Upon receiving the text block transmitted from the partner station, the communication control processor 5 executes a check process by BCC (steps S11 and S12). When an abnormality is detected by this check processing, the communication control processor 5 sends a negative response (NAK) to the partner station (step S17). The partner station executes a predetermined NAK process (retry process or the like) in response to the reception of the negative response.

Here, in the present invention, even if the result of the check processing by BCC is normal, the communication control processor 5
Executes the check processing of the control information of the received text block (step S14). That is, the communication control processor 5 reads the start information (ST) and the end information (ET) from the set parameter information block from the internal memory, and the start information (ST) and the end information (ET) of each received text block. Compare with. Based on the comparison result, it is determined that the control information is normal, and that the control information is abnormal, and the control information is abnormal.

When the result of each check process of BCC and control information is normal, the communication control processor 5 acknowledges that the received text block is normal (AC).
K) is transmitted to the partner station (step S16). When the result of the control information check processing is abnormal, the communication control processor 5 transmits a negative response (NAK) to the partner station (step S17). The partner station executes a predetermined NAK process (retry process or the like) in response to the reception of the negative response.

When the communication control processor 5 receives the last text block, it shifts to the phase of terminating the communication line or disconnecting the data line (link disconnection), as shown in FIG. 5B. That is, the transmission from the partner station ends (EO
When the control information of T) is received, the communication ends (YES in step S18).

In this embodiment, the start information (ST) and end information (ET) of the first text block to be transmitted and received are arbitrarily set as communication parameter information. Therefore, when transmitting a text block, it is possible to set it according to the control information supported by the partner station. Thereby, for example, for the data communication control device of the station which does not use the control information according to the JIS standard code, the compatibility of data transmission / reception is ensured by changing the JIS standard code into the control information of the corresponding code. be able to. In other words, it is possible to establish a communication connection with a data communication control device that employs a special text format transmission block format.

Second, not only the BCC check process but also the control information check process is executed. Accordingly, when the control information is abnormal, the negative acknowledgment (NAK) can be transmitted without transmitting the positive acknowledgment (ACK) to the partner station that transmitted the data. Therefore,
By receiving the negative response (NAK) on the partner station side, predetermined error processing (data recovery etc.) is executed without discarding the transmitted data. In other words, it is possible to prevent a situation in which a positive response (ACK) is transmitted and the data transmitted by the partner station is discarded even though the control information is abnormal.

[0030]

As described in detail above, according to the present invention, first, when a text block to which control information such as start information and end information is added is transmitted and received by a predetermined transmission control procedure, the control information is transmitted. It can be set arbitrarily. Therefore, compatibility of data transmission / reception can be ensured for a station using specific control information, and as a result, versatility can be improved.

Secondly, by providing the check function of the control information added to the text block, the entire data in block units can be surely checked. Therefore,
Even if a text block with abnormal control information is received, without sending an acknowledgment to the sender of the data,
It is possible to reliably send a negative response. This allows
As a result, it is possible to prevent a situation in which abnormal data is mistakenly discarded and to reliably perform recovery or analysis of abnormal data.

[Brief description of drawings]

FIG. 1 is a block diagram showing a data communication system according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram for explaining the contents of communication parameter information and transmission / reception data according to the embodiment.

FIG. 3 is a flowchart for explaining the operation of the embodiment.

FIG. 4 is a flowchart for explaining the operation of the embodiment.

FIG. 5 is a diagram for explaining a transmission control procedure of the embodiment.

[Explanation of symbols]

1 ... Data communication control device, 2 ... Partner station, 3 ... Communication line,
4 ... Processor (CPU), 5 ... Communication control processor,
6 ... Memory for application program, 7 ... Modem.

Claims (6)

[Claims] 1. A data communication control device for transmitting / receiving block unit data to / from a partner station according to a predetermined transmission control procedure, including control including start information and end information of the block unit data in response to an instruction from the outside. Control information setting means for setting information, transmitting means for transmitting the block-unit data added with the control information set by the control information setting means to the partner station at the time of data transmission, and the partner station at the time of data reception A data communication control device, comprising: receiving means for receiving the block-unit data added with the control information transmitted from the device. 2. A data communication control device for transmitting / receiving block unit data to / from a partner station according to a predetermined transmission control procedure, including control including start information and end information of the block unit data in response to an instruction from the outside. Control information setting means for setting information, transmitting means for transmitting the block-unit data added with the control information set by the control information setting means to the partner station at the time of data transmission, and the partner station at the time of data reception A data communication control device, comprising: a receiving unit that receives the block-unit data transmitted from the device and executes a check process of the received data based on the control information added to the received data. . 3. A data communication control device for transmitting / receiving block-unit data to / from a partner station according to a predetermined transmission control procedure, including control including start information and end information of the block-unit data in response to an instruction from the outside. Control information generation means for generating information, storage means for storing the control information generated by the control information generation means, and data in block units to which the control information stored in the storage means at the time of data transmission is added And a means for transmitting to the other station, receiving the block unit data transmitted from the other station at the time of data reception, and performing a check process based on the check information added to the received data,
A data communication control device comprising: a receiving unit that executes a check process based on a comparison result of the control information added to the received data and the control information stored in the storage unit. 4. A data communication control device for transmitting / receiving block-unit data to / from a partner station in accordance with a predetermined transmission control procedure, the control including start information and end information of the block-unit data in response to an instruction from the outside. The step of setting information, the step of receiving the data in block units transmitted from the partner station at the time of data reception, and the control information added to the received data received and the set control information are compared. And a step of transmitting a negative response to the partner station when the comparison result does not match, or a positive response to the partner station when the comparison result matches. Control device data transfer check method. 5. A data communication control device for transmitting / receiving block-unit data to / from a partner station according to a predetermined transmission control procedure, control including start information and end information of the block-unit data in response to an instruction from the outside. Setting information, receiving the block unit data transmitted from the partner station at the time of data reception, and performing a check process based on the check information added to the received data received, A step of comparing the control information set with the control information added to the received data, and when an error is detected by a check process based on the check information or when the comparison result of the control information does not match. And a step of transmitting a negative response to the partner station. Over data transfer check method. 6. A data communication system for transmitting / receiving block unit data between a plurality of stations according to a predetermined transmission control procedure, wherein start information and end of the block unit data are transmitted to each station in response to an instruction from the outside. When data is transmitted from a transmitting side station between control information setting means for setting control information including information and each station where a data link is established, the control information set by the control information setting means is added. The transmitting means for transmitting the data in the block unit and the station on the receiving side between the stations having the data link established receive the data transmitted by the transmitting means and set by the control information setting means. A data communication system comprising: a receiving unit that checks the received data based on control information.