JPH0621927A - Data transmission system - Google Patents

Abstract

PURPOSE:To unnecessitate the detour circuit that is added in a full double communication mode by carrying out the transmission of data after switching the full double communication mode to a semidouble communication mode against a transmission fault that causes the break of data. CONSTITUTION:A received data break detecting circuit 103 detects the break of the received data and controls a break information inserting/switching circuit 105 to send the break information received from a received data break information generating circuit 104 to a called station A. Then the circuit 103 controls a transfer system switching circuit 106 to switch the communication of a transmission line 120 to a semidouble communication mode via a semidouble communication control circuit 107. Thus the data to be inputted to a station B 102 are sent to the station A via the line 120 in the semidouble communication mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system which is used in a data transmission system and performs data transmission by switching from full-duplex to half-duplex to a data failure communication failure.

[0002]

2. Description of the Related Art Conventionally, in a data transmission system, data transmission is performed in full duplex by providing a bypass line different from the working line. Then, when a communication failure due to data transmission interruption occurs, the data transmission can be continued using the bypass line.

[0003]

As described above, the conventional data transmission system has a problem that it is necessary to provide a detour line in addition to the normal line, assuming a communication failure due to a data transmission interruption.

The present invention solves the problems in the prior art as described above, and it is possible to switch from full-duplex to half-duplex to a communication failure of data loss to perform data transmission. An object of the present invention is to provide a data transmission method that can eliminate the need for a bypass line additionally provided.

[0005]

In order to achieve the above object, the present invention is directed to two full-duplex transmission lines connected to each other, and when one transmission line fails in transmission data disconnection, the other transmission line. In a data transmission method for performing half-duplex data transmission by using, reception data loss detection means for detecting disconnection of received data from two transmission paths, and reception data for notifying the opposite station of the reception data loss Reception data disconnection information generating / sending means for generating disconnection information and transmitting from the other transmission line when a failure occurs, and disconnection information detecting means for detecting reception data disconnection information generating / sending means in the opposite station And a transmission method switching means that is connected to two transmission paths and switches the transmission method from full-duplex to half-duplex according to an input switching control signal, and a reception data disconnection detection means detects disconnection of received data, and , Disconnect information A half-duplex communication control means for sending a switching control signal to the transmission method switching means when the detection means detects the reception data disconnection information is provided. Further, the reception data disconnection information generating / sending unit is configured to include a disconnection information insertion switching unit for inserting the generated reception data disconnection information into the input data.

[0006]

According to the data transmission method of the present invention having the above structure, the transmission method is switched from full duplex to half duplex when the disconnection of the received data is detected and the received data disconnection information is detected. Therefore, it is possible to switch from full-duplex transmission status to a data failure communication failure to half-duplex and continue data transmission, eliminating the need for an additional bypass line for full-duplex. Become.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the data transmission system of the present invention will be described with reference to the drawings. FIG. 1 shows the configuration of the embodiment. In FIG. 1, this example includes a station (A) 101 and a station (B) 102, and the station (A) 101 and the station (B) 1
02 is connected to a transmission line 119 and a transmission line 120, and data transmission is performed by one-way transmission using the transmission line 119 and the transmission line 120.

The station (A) 101 has a disconnection information detection circuit 108 for detecting the reception data disconnection information transmitted from the station (B) 102 to the transmission line 120, and transmission for switching to half-duplex transmission on the transmission line 120. The system switching circuit 109, a half-duplex communication control circuit 110, and a reception data loss detection circuit 111 that detects a reception data loss on the transmission path 120 are included.
Furthermore, by detecting the reception data disconnection on the transmission path 120,
Reception data break information generation circuit 112 for transmitting the reception data break information to the station (B) 102 through the transmission line 119.
And a disconnection information insertion switching circuit 113 for switching to insert the reception data disconnection information into the input data, and a transmission method switching circuit 114 for switching between full-duplex and half-duplex transmission.
And a half-duplex communication control circuit 115.

The station (B) 102 has a reception data disconnection detection circuit 103, which operates in the same manner as the station (A) 101, a reception data disconnection information generation circuit 104, and a disconnection information insertion switching circuit 10.
5, a transmission system switching circuit 106, and a half-duplex communication control circuit 107. Furthermore, the disconnection information detection circuit 1
16, a transmission system switching circuit 117, and a half-duplex communication control circuit 118. Next, the operation of the configuration in this embodiment will be described. When there is no communication failure, the input data to the station (A) 101 is the disconnection information insertion switching circuit 113, the transmission method switching circuit 114,
It is transmitted to the station (B) 102 through the transmission line 119. The station (B) 102 sends the data as output data through the transmission system switching circuit 117. Input data to the station (B) 102 is transmitted to the station (A) 101 through the disconnection information insertion switching circuit 105, the transmission system switching circuit 106, and the transmission path 120. The station (A) 101 sends it as output data through the transmission system switching circuit 109.

Next, a case where a failure of transmission data interruption occurs on the transmission paths 119 and 120 will be described. Here, it is assumed that the transmission line 119 has a fault of reception data disconnection due to a transmission fault. First, when the reception data disconnection detection circuit 103 in the station (B) 102 detects the reception data disconnection, it controls the disconnection information insertion switching circuit 105 to transmit the disconnection information from the reception data disconnection information generation circuit 104 to the opposite station ( A) Send to 101. Further, the reception data loss detection circuit 103 in the station (B) 102 controls the transmission method switching circuit 106 to change the transmission method on the transmission path 120 to the half-duplex communication control circuit 1.
Switch to half-duplex transmission according to 07. After that, station (B) 1
The input data to 02 is transmitted to the station (A) 101 by half-duplex using the transmission line 120.

On the other hand, in the station (A) 101, the disconnection information detection circuit 108 detects disconnection information from the station (B) 102,
The transmission line switching circuit 109 is controlled to control the transmission line 120.
The transmission is switched to the half-duplex transmission method by the half-duplex communication control circuit 110. Through the above operation, the transmission line 120
Half-duplex transmission in is established. Note that, even when data interruption occurs due to a transmission failure on the transmission line 120, half-duplex transmission is performed on the transmission line 119 by the same operation.

[0012]

As described above, the data transmission system of the present invention switches the transmission system from full-duplex to half-duplex when the reception data disconnection is detected and the reception data disconnection information is detected. Therefore, it is possible to switch from full-duplex transmission status to communication failure of data loss to half-duplex and continue data transmission, and in the case of full-duplex, an additional bypass line is provided. It has the effect of being unnecessary.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a station A in an embodiment of a data transmission system of the present invention.

FIG. 2 is a block diagram showing a configuration of a B station in the embodiment of the data transmission system of the present invention.

[Explanation of symbols]

 101 station (A) 102 station (B) 103 reception data disconnection detection circuit 104 reception data disconnection information generation circuit 105 disconnection information insertion switching circuit 106 transmission system switching circuit 107 half-duplex communication control circuit 108 disconnection information detection circuit 109 transmission system switching Circuit 110 Half-duplex communication control circuit 111 Received data disconnection detection circuit 112 Received data disconnection information generation circuit 113 Disconnection information insertion switching circuit 114 Transmission method switching circuit 115 Half-duplex communication control circuit 116 Disconnection information detection circuit 117 Transmission method switching circuit 118 Half-duplex communication control circuit Transmission line 119,120 Transmission line

Claims (2)

[Claims] 1. A data transmission system in which two full-duplex transmission lines are connected and when the transmission data disconnection failure occurs in one of the transmission lines, the other transmission line is used to perform half-duplex data transmission. In this case, a reception data disconnection detecting means for detecting disconnection of the reception data from the two transmission paths, and reception data disconnection information for notifying the opposite station of the reception data disconnection, and the other of them when a failure occurs Connected to the above two transmission lines, a reception data disconnection information generation / transmission means for transmitting from the transmission line, a disconnection information detection means for detecting reception data disconnection information from the reception data disconnection information generation / transmission means in the opposite station, Transmission mode switching means for switching the transmission method from full-duplex to half-duplex by an input switching control signal, and the reception data disconnection detection means detects disconnection of the reception data,
And a half-duplex communication control means for sending the switching control signal to the transmission method switching means when the disconnection information detecting means detects the reception data disconnection information. 2. The data transmission system according to claim 1, wherein the reception data disconnection information generating / transmitting means comprises a disconnection information insertion switching unit for inserting the generated reception data disconnection information into the input data.