JPS6040745B2 - fiber optic communication equipment - Google Patents

Description

[Detailed Description of the Invention] This invention connects multiple information generation and reception points with an optical fiber cable that is commonly used for all information transmission, and uses this common optical fiber cable in a time-sharing manner. The present invention relates to an optical fiber communication device for exchanging information between arbitrary information generation and reception points.

An example of this type of device is shown in FIG. 1.

In the figure, 2a, 2b, . . . 2g are optical branching/coupling devices that enable the transmission and reception of signals between any optical fiber cables connected to them, and these are la, lb, . . .
They are connected in cascade by optical fiber cables indicated by lh. Reference numeral 3 designates an optical switch connecting one end of the optical fiber transmission system formed as described above to the end, 4 a synchronization signal generator, and 5 a disconnection detector.

The output of the disconnection detector 5 is led to the optical switch 3 and drives it. 6a, 6b, . . . , 6e are optical information transmission devices provided at each information generation/reception point, and these, a disconnection detector 5, and a synchronization signal generator 4 transmit signals between these and the optical fiber cable system. They are connected to optical fiber cables la, lb, ..., lh via optical branching couplers 2a, 2b, ..., 2g so that they can send and receive information.

Next, the operation of the optical fiber communication device shown in FIG. 1 will be explained.

The synchronization signal generator 4 generates a synchronization signal intermittently, and transmits the synchronization signal to the disconnection detector 5 and the optical information transmission bag counterfeit 6a, 6b, . . .
・, 6e. Each optical information transmission device 6a, 6b, .
. . , 6e transmits its own transmission information intermittently while maintaining a fixed time relationship determined for each optical information transmission device with the synchronization signal reception timing. At this time, each optical information transmission device 6a, 6b is arranged so that the transmission signal sent out by one optical information transmission device does not overlap in time with any signal sent out by the other optical information transmission device or the synchronization signal generator 4. ,...,
The relative relationship between the signal transmission timing of 6e and the synchronization signal reception timing is determined. On the other hand, all the signals sent out in this way are transmitted through optical fiber cables lb, l.
c,..., 1g and optical branch/coupler 2a, 2b,...
, 2g to all optical information transmission devices 6a, 6b, .
..., 6e and the disconnection detector 5 are reached.

Therefore, each optical information transmission device 6a, 6b, ..., 6e utilizes the relative time relationship between the synchronization signal and the received signal, the identification code provided in the received signal, etc. Separate and extract the signal components sent to itself from the received signal. The optical fiber communication device shown in FIG. 1 enables communication between arbitrary optical information transmission devices using the method described above. Optical fiber cable lb, lc,...
, 1g is damaged and disconnected, communication between all or part of the optical information transmission devices becomes impossible.

When such a situation occurs, the disconnection detector 5 detects the occurrence of a disconnection fault by losing part or all of the signal reaching it, and generates a disconnection detection signal. The optical switch 3 receives this disconnection detection signal and changes the normally open state to the open state. By switching the optical switch 3, even after a disconnection fault occurs, normal communication can continue as before the disconnection fault occurs. In addition, when continuing communication with the optical switch 3 in the closed circuit state as described above, in preparation for the occurrence of the next disconnection fault, quickly find the point of failure and place the optical switch 3 in the closed circuit state again to communicate. It is desirable to repair the point of failure so that it can be carried out.
Since conventionally known optical fiber communication equipment is configured as described above, a test signal transmission test is performed between adjacent optical information transmission equipment in order to find the fault point when repairing the fault point. Therefore, testing must be conducted at the locations of a large number of optical information transmission devices that are installed spatially apart, which has the drawback of requiring a great deal of effort and time.

Additionally, there are disadvantages such as the need for special test equipment to conduct transmission tests without interfering with the signals being communicated at the time, or the need to temporarily interrupt normal communication during testing. There was also. This invention was made in order to eliminate the above-mentioned drawbacks, and by providing a wire breakage position detector adjacent to the synchronization signal, when a wire breakage fault occurs, it is possible to determine which optical information transmission device and which optical information transmission device the wire breakage fault is caused by. By displaying whether a problem has occurred with the device, the effort and time required to repair the point of failure can be greatly reduced.
The purpose of this is to provide an optical fiber communication device that is more reliable and easier to maintain. An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2, 2a, 2b, . . . , 2g are optical branching couplers, and these are connected by optical fiber cables indicated as lb, lb, . . . , lh. Reference numeral 3 denotes an optical switch that connects one end of the optical cable transmission system thus formed and the end of the cable.

Further, 4 is a synchronizing signal generator, 5 is a wire breakage detector, and 7 is a wire breakage position detector, which can store and display the reception status of the signal sent through the optical cable transmission system when a wire breakage fault occurs. A wire breakage detection signal output from the wire breakage detector 5 is guided to a wire breakage position detector 7 to activate it. The optical switch drive signal, which is the output of the disconnection position detector 7, is guided to the optical switch 3, and changes the optical switch 3, which is normally open, to a closed state. 6a, 6b, . . . , 6e are spatially distributed optical information transmission devices, and communication, which is the purpose of the entire device, is performed between these optical information transmission devices.

Next, the operation of the embodiment of the present invention shown in FIG. 2 will be explained.

The manner of communication performed between each optical information transmission device is similar to that of the conventional optical fiber communication device described above. That is, each of the optical information transmission devices 6a to 6e sends out its own transmission signal while maintaining a fixed timing relationship with respect to the synchronization signal generated intermittently by the synchronization signal generator 4. At this time, the timing relationship is set so that the transmission signals generated by the plurality of optical information transmission devices 6a to 6e do not overlap in time. Meanwhile, all of the signals generated in this way reach all the optical information transmission devices 6a to 6e through the optical fiber cables la to lh. Each of the optical information transmission devices 6a to 6e separates and extracts the signal component transmitted toward itself from among the signals thus received. If a disconnection fault occurs in the optical fiber cables indicated by lb, lc, ..., 1g while communication is being carried out between multiple optical information transmission devices using the method described above, a disconnection detector will be activated. 5 is a synchronization signal generator 4 and an optical information transmission device 6a,
When all or part of the signals sent from 6b, .
When the disconnection position detector 7 receives the disconnection fault detection signal, it activates the synchronization signal generator 4 and the optical information transmission devices 6a, 6b, . . .
, 6e, and displays the contents. This stored/displayed content is retained until a manual reset operation outside the operator is performed. Following this storage and display of the signal reception state, the disconnection position detector 7 sends a switching signal to the optical switch 3. This switching signal has the effect of switching the optical switch 3, which is normally open, to a closed state. By closing the optical switch 3, the optical fibers lb, l
The optical information transmission devices 6a, 6b, . . . c, .
..., 6e can restore normal communication between all or part of them. On the other hand, the synchronization signal generator 4 and the optical information transmission devices 6a, 6b, . The reception status of the signal sent from 6e is the optical fiber cable lb, lc,
. . . varies depending on which of the 1g a disconnection fault occurs.

For example, when the optical fiber cable lc is disconnected, only the transmission signals from the synchronization signal generator 4 and the optical information transmission device 6a can be received, and when the optical fiber cable ld is disconnected, the synchronization signal generation device 4 and the optical information transmission device 6a can be received. ,6
When the transmission signal b is broken in the optical fiber cable 1g, the synchronization signal generator 4 and the optical information transmission devices 6a, 6b,
..., all of the transmission signals from 6e can be received. In this way, there is a one-to-one correspondence between the optical fiber cable in which the disconnection fault has occurred and the signal reception status stored and displayed by the disconnection position detector.
Conversely, when a breakage fault occurs, the optical fiber cable that caused the breakage fault can be identified from the stored display contents of the breakage position detector. In the above embodiment, the disconnection detector 5 and the synchronizing signal generator 4 are provided to sandwich the optical switch 3, but they may be provided adjacent to each other.

Furthermore, the same effect can be obtained by providing a group of the synchronizing signal generator 4, wire breakage detector 5, and wire breakage position detector 7 not adjacent to the optical switch 3 but between any adjacent optical information transmission devices. . Furthermore, in the previous embodiment, an independent synchronizing signal generator 4 for generating a synchronizing signal is provided, but this can be removed and any one optical information transmitting device selected from the entire optical information transmitting device can be used. The transmitted signal can also be used as a synchronization signal. Furthermore, the content stored by the wire breakage position detector does not necessarily have to be the signal reception state itself, but may be any wire breakage position information that can be derived from the signal reception state itself. As described above, according to the present invention, when a disconnection fault occurs, it is possible to identify the optical fiber cable in which the fault has occurred, so that the fault point can be quickly searched and repaired after the fault occurs. This eliminates the inconvenience of temporarily stopping the normal operation of the system in order to search for failure points and preparing special test equipment. Through these, it is possible to realize an excellent optical fiber communication system with high availability and operational reliability and low maintenance costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the structure of a subordinate optical fiber communication device, and FIG. 2 is a block diagram showing the structure of an optical fiber communication device according to an embodiment of the present invention. la, lb,..., lh...optical fiber cable, 2a,
2b,..., 2g... Optical branching coupler, 3...
... Optical switch, 4 ... Synchronization signal generator, 5 ... Disconnection detector, 6a, 6b, ..., 6
e... Optical information transmission device, 7... Disconnection position detector. Note that the same reference numerals in the figures indicate the same or corresponding parts. Figure 1 Figure 2

Claims (1)

[Claims] 1. An annular optical transmission line formed by cascading a plurality of optical fiber cables and a plurality of optical branching couplers, and connecting the start and end ends of the line with an optical switch that is always open;
A plurality of optical information transmission devices coupled to the annular optical transmission line via the optical branching coupler, and disconnection detection for detecting a disconnection failure occurring in the annular optical transmission line and converting the optical switch to a closed state. In an optical fiber communication device equipped with an optical fiber communication device, when the disconnection fault occurs, the optical switch receives a signal sent through the annular optical transmission line before the disconnection detector switches the optical switch to a closed state. An optical fiber communication device characterized by comprising a disconnection position detector that detects and stores and displays a disconnection fault occurrence part of the optical transmission line based on the state.