JPH07118692B2 - Data repeater - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a data repeater suitable for a half-duplex communication system that performs bidirectional data transmission by one line.

<< Outline of the Invention >> In the present invention, a plurality of external terminals for relay to which bidirectional single lines from each system are respectively connected are provided,
Each relay external terminal is equipped with a transceiver capable of receiving data from each line and transmitting data to each line, sets all transceivers to receive mode and waits, and receives data with one of the transceivers. In response to this, another transceiver is switched to the transmission mode, and the reception data from the transceiver in the reception mode is transferred to the transceiver in the transmission mode as the transmission data.

<< Prior Art and Its Problems >> Conventionally, when performing duplex communication using two unidirectional data lines, a configuration of a data repeater shown in FIG. 8 (a) is known.

That is, the data from the left side is received by the receiver 1 and transmitted by the driver 2. The data from the right side is received by the receiver 4 and transmitted by the driver 3.

Thus, in this data repeater, double communication can be performed without instructing the direction of data from the outside.

On the other hand, when half-duplex communication is performed using only one bidirectional data line, the structure of the data repeater shown in FIG. 8 (b) is known.

In this configuration, receiver 1a and driver 3a or driver
Since only one of 2a and receiver 4a can be activated, it is necessary to switch the receiver-driver pair in each direction by externally instructing the direction of data in advance, which makes control complicated. was there.

<< Object of the Invention >> An object of the present invention is to use only one bidirectional data line, and without instructing the direction of data from the outside.
It is to provide a data repeater capable of performing half-duplex data communication.

<< Structure and Effect of the Invention >> In order to achieve the above-mentioned object, the present invention has a plurality of relay external terminals to which bidirectional single lines from each system are respectively connected, data reception from each line, and In order to enable data transmission to the line, transceivers provided for each relay external terminal and all transceivers are set to receive mode and stand by, and data is received by either transceiver. In response, another transceiver is switched to the transmission mode, and the control means for transferring the received data from the transceiver in the reception mode to the transceiver in the transmission mode as the transmission data is provided. .

According to such a configuration, there is an effect that only one bidirectional data line is used and half-duplex data communication can be performed without instructing the data direction from the outside.

<< Description of Embodiments >> FIG. 1 is an explanatory view showing an algorithm for switching between transmission and reception of a transceiver in a data repeater according to the present invention, and FIG. 2 is a configuration diagram of the data repeater according to the present invention, FIGS. The figure shows the operation flow. FIG. 5 shows another embodiment according to the present invention.

In Fig. 1 (a), both transceivers are waiting for data.
Both 11 and 12 are in the receiving state and can receive data from either left or right. By receiving the data, the transceiver on the other side is switched to the transmission and the data is transmitted.

In FIG. 1 (b), there are three input / output lines,
While waiting for data, all three transceivers 13, 14 and 15 are in a receiving state. For example, when 13 transceivers receive data, the transceivers 14, 15 are set to the transmit state and then the data is sent out.

FIG. 2 is a block diagram of an embodiment according to the present invention of a data repeater used to achieve the above algorithm. In this case, the single-wire bidirectional optical transmission module 32 is provided with a transmission / reception switching terminal 31, and in the transmission / reception switching algorithm, the same function as the transceiver in FIG. 1 is performed. FIG. 3 shows the flow when the data is now received from the transceiver 21 side.

First, when the power is turned on, both the transceiver 21 and the optical module 32 are set to the receiving state. At this time, the receiver 30 is ON
The driver 29 is in the OFF state. Further, the reception signal gates 23 and 28 are in a gate open state, and are in a data relayable state.

Receiver 30 is always on when data enters transceiver 21
Therefore, the signal is immediately sent to the signal detection circuit 22. Now detect the data and know that it came.

The data then passes through the reception signal gate 23 and enters the signal delay circuit 26. During this time, the transmission / reception direction control circuit 25 switches the optical module 32 to transmission and closes the reception signal gate 28.

The function of the signal delay circuit 28 is to delay the transmission of data until the switching operation is completed in order to prevent the data from being truncated due to the switching time t to the transmission of the optical module 32 and the switching time of the reception signal gate 28. There is a point to let.

Next, the data is E / O converted by the optical module 32 and transmitted.

On the other hand, the signal transmission completion detection circuit 24 knows that the last bit of the data has been transmitted, and notifies the transmission / reception direction control circuit 25. The transmission / reception direction control circuit 25 switches the optical module 32 to the reception state and, at the same time, opens the reception signal gate 28 to return to the initial state.

When data is received from the optical module 32, the flow is as shown in FIG. 4, and is almost the same as that from the transceiver 21.

FIG. 5 shows another embodiment of the present invention.
This is an example of using individually. The data received from the transceiver 21 is transmitted from the two optical modules 32 and 34. The data received from the optical module 34 is transmitted from the optical module 32 and the transceiver 21.

6 and 7 show an example in which the present invention is used in the transmission system of the single-line bidirectional transmission module 32, and FIG. 6 shows an example in which a part of the bus line is converted into an optical system. Since it receives data from both left and right, it can be used in the half-duplex communication system.

FIG. 7 shows an example in which a bus line is composed of optical fibers,
It is composed of two optical modules 32 and a transceiver 21 connected to the secondary station.

[Brief description of drawings]

FIG. 8 (a) is a block diagram showing a conventional example of a data repeater using two unidirectional data lines, and FIG. 8 (b) is a conventional data repeater using two bidirectional data lines. FIG. 1 is a block diagram showing an example, FIG. 1 is a schematic diagram for explaining an algorithm of transmission / reception switching of a transceiver in a data repeater according to the present invention, and FIG. FIG. 4 is a flow chart showing its operation, FIG. 5 is a block diagram showing another embodiment of the present invention, FIG. 6 is a block diagram showing an example in which a part of a bus line is converted to light, and FIG. 7 is an optical fiber. FIG. 3 is a block diagram showing an example in which a bus line is configured with. 1 ... Bidirectional single line 2 ... External terminal for relay 3 ... Transceiver

Claims (1)

[Claims] 1. A plurality of relay external terminals to which bidirectional single lines from each system are respectively connected, and for each relay so that data can be received from each line and data can be transmitted to each line. The transceivers provided for each external terminal and all transceivers are set to receive mode and wait, and in response to data being received by one of the transceivers, other transceivers are switched to transmit mode and receive. A data repeater, comprising: a control unit that transfers received data from a transceiver relating to a mode to the transceiver relating to a transmission mode as transmission data.