JPS636925A - Communication equipment - Google Patents

Abstract

PURPOSE:To disconnect an optional transmission/reception equipment and to add it without intermitting the correspondence by using a reception optical fiber and a transmission optical fiber so as to connect plural interface circuits connected in series on the bus line and the transmission/reception equipment thereby preventing the signal reflection. CONSTITUTION:An optical interface 8 is connected to a work station 2. An optical banch cable is formed by optical fibers 13, 14, the work station 2 receives a signal from a trunk cable 3 through the optical fiber 13 and sends a signal to a trunk cable 3 through the optical fiber 14. Even if an optional work station is disconnected during the operation of the system, since the terminals A1, A3 and the terminals B1, B3 of the connector box 4 are connected via the optical interface circuit 7, the connection of the entire system is maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a communication device comprising a plurality of transceivers connected to a common bus line.

[Summary of the invention]

The present invention prevents signal reflection by connecting a plurality of interface circuits connected in series on a bus line and a transceiver using a receiving optical fiber and a transmitting optical fiber, and also prevents communication operations. To provide a communication device in which any transmitter/receiver can be disconnected and added without interrupting communication.

[Conventional technology]

FIG. 2 shows a conventional communication device in which a workstation 2 consisting of a plurality of transmitters and receivers is connected to one main computer 1 via a trunk cable 3. As shown in FIG.

In FIG. 2, the trunk cable 3 is provided with a plurality of connector boxes 4 with terminators, and the main computer 1 and each workstation 2 are connected to the connector box 4 via branch cables 5, and are connected to the trunk cable 3, respectively. are connected in parallel.

Note that 6 is an interface in the workstation 2. Matching resistors RT having a size equal to the impedance of the trunk cable 3 are connected to both ends of the trunk cable 3 to prevent reflection of electrical signals.

According to the above configuration, communication can be performed between the main computer 1 and each workstation 2 using the trunk cable 3 as a common bus line. However, in such a configuration, both ends of the trunk cable 3 are matched, but both ends of the branch cable 5 connecting each connector box 4 and the workstation 2 are not matched. Therefore, the signal branched from the connector box 4 is reflected at the workstation 2, affecting the bus line signal transmitted by the trunk cable 3, and the correct signal transmission may not be performed.

To solve this problem, the configuration shown in FIG. 3 is widely used.

In FIG. 3, terminals A1 and A of the connector box 4,
At the same time as separating B, and B, A, and A3
and interface 6 on workstation 2
Commonly connected to terminal A2 of B.

and B3 are commonly connected to the terminal B2 of the interface 6. That is, A IA Z A 3 transmission line and B
+ Bz B3 transmission line is formed so that each workstation 2 reads directly from the trunk cable 3 in series, thereby preventing signal reflection in the branch cable 5. Also, if you want to disconnect any workstation 2 from the system,
1 and B1 and B.

The entire system is connected by connecting them through jumper connectors.

[Problem that the invention seeks to solve]

Although the configuration shown in Figure 3 can effectively eliminate signal reflections on the trunk cable 3 and branch cable 5, it is possible to replace or repair any part of the workstation 2 while the system shown in Figure 3 is in operation. , when the corresponding connector box 4 is disconnected for movement etc., the above A
1 and A3 and between B1 and 83, system communication will be interrupted.

The present invention aims to solve the above problems.

[Means for solving problems]

In the present invention, a plurality of interface circuits connected in series on a bus line, a first electrical-to-optical converter and a first optical-to-electrical converter provided in the interface circuit, and a plurality of interface circuits connected in series on the bus line; a plurality of transceivers that transmit and receive signals to and from the transceiver, a second optical-to-electrical converter and a second electric-to-optical converter provided in the transmitter-receiver, the first electric-to-optical converter and the above-mentioned A first optical fiber connecting the second optical-to-electrical converter and a second optical fiber connecting the first optical-to-electrical converter and the second electric-to-optical converter. ing.

[Effect]

Since the first and second optical fibers form an optical branch cable having a receiving optical fiber and a transmitting optical fiber, it is possible to prevent signal reflection in the branch cable and to prevent signal reflection during communication operation of the system. It becomes possible to disconnect and add transceivers without interrupting communication.

〔Example〕

In FIG. 1, an optical interface 7 is connected to the connector box 4, and an optical interface 8 is connected to the workstation 2. The connection between the optical interface 7 and the connector box 4 is substantially the same as the connection between the interface 6 and the connector box 4 in FIG. 3 described above. That is, by commonly connecting the terminals A and A3 of the connector box 4 to the terminal A2 of the optical interface 7, and by commonly connecting the terminals B and 83 of the connector box 4 to the terminal B2 of the optical interface 7. A.

A transmission line of Az Ax and a transmission line of B+Bz Bi are formed.

Further, an E10 converter (electrical-optical converter) 9 is provided on the output side of the optical interface 7, and an O/E converter (optical-electrical converter) 10 is provided on the input side. Furthermore, an O/E converter 1 is connected to the input end of the optical interface 8.
1 is provided, and an E10 converter 12 is provided on the output side. And the E10 converter 9 and the O/E converter 11
are connected via an optical fiber 13, and the 0/E converter 10 and the E10 converter 12 are connected via an optical fiber 14.

According to the above configuration, the optical fibers 13 and 14 substantially form an optical branch cable, and the workstation 2 receives signals from the trunk cable 3 through the optical fiber 13 and sends signals to the trunk cable 3 through the optical fiber 14. Can be sent.

Therefore, signal reflection between the workstation 2 and the connector box 4 can be prevented. Also, any workstation 2 while the system is running
Even if the connector box 4 is disconnected, the connections between terminals A1 and A3 and terminals B and B1 of the connector box 4 are maintained via the optical interface 7, so the connection of the entire system can be maintained, so that communication is not interrupted. It can prevent kudzu. Further, the workstation 2 can be newly connected to the vacant connector box 4 while the system is in operation.

Note that the connector box 4 and the optical interface 7 can be directly connected using a connector. Also, if necessary, connect the connector box 4 and the workstation 2 between the main computer 1 and the connector box 4.
An optical branch cable may be formed by providing the same configuration as that between.

〔Effect of the invention〕

According to the present invention, signal reflection in branch cables can be prevented and signals can be transmitted accurately. Further, while the system is in operation, any workstation can be disconnected or newly added without interrupting communication.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing an example of a conventional communication device, and Fig. 3 is a block diagram showing an example of a conventional communication device. It is a block diagram showing an example of a device. In addition, in the symbols used in the drawings, 2--------1----Workstation 3----m=------Trunk cable 4
−・−・・−・−１−−−−−−・−・Connector box? , ----------...-- Optical interface 10.11 --- Optical-to-electrical converter 9.1
2.--Electro-optical converter 13, 14...
...... It is an optical fiber.

Claims (1)

[Scope of Claims] A plurality of interface circuits connected in series on a bus line, a first electrical-optical converter and a first optical-electrical converter provided in the interface circuit, and the bus line. a plurality of transceivers that send and receive signals to and from the transmitter/receiver; a second optical-to-electrical converter and a second electric-to-optical converter provided in the transmitter-receiver; and the first electric-to-optical converter. a first optical fiber that connects the second optical-to-electrical converter; and a second optical fiber that connects the first optical-to-electrical converter and the second electric-to-optical converter. A communication device characterized in that: