JPH02285818A - Line changeover device - Google Patents

Abstract

PURPOSE:To discriminate the line quality of a branch route by branching a signal of a receiver side active line with a branching circuit, outputting the signal to a monitor changeover device and inputting the branched signal inputted to a synchronizing changeover circuit to a fault detector before an in-circuit changeover switch. CONSTITUTION:When a synchronization changeover circuit 8 selects an active line 100, a branch signal being a signal of the active line 100 branched from the branch circuit 13 is inputted to the synchronization changeover circuit 8 via a monitor changeover device 14. Then the branch signal inputted to the synchronization changeover circuit 8 is fed to a fault detector 15 before the changeover switch. Thus, the fault detector 15 detects a fault by the branch signal. In this case, since the monitor changeover device 14 is provided near a distribution circuit 7, the quality of a standby line of a distribution route from the distribution circuit 7 up to the synchronization changeover circuit 8 is monitored by the detection of the said fault detector 15.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a line switching device, and particularly to a line switching device that monitors the line quality of a protection line that rescues a working line.

[Prior Art] FIG. 2 shows a circuit block diagram of a conventional line switching device, in which the working line 100 and the protection line 200 are provided with the same circuit. In other words, the transmission system branch circuit l
includes a transmission code conversion circuit 2.2a, a transmission signal processing circuit 3,
3a is provided, and a frame synchronization circuit 4.4a is provided in the receiving system.
, received signal processing circuits 5, 5a, received code conversion circuit 6゜6
A is provided. Further, the protection line 200 includes a distribution circuit 7 that distributes the signal sent to the protection line 200 to the working line 100 when the working line 100 is rescued, and the working line 100 has a distribution circuit 7 that distributes the signal sent to the protection line 200 to the working line 100. 100
A synchronous switching circuit 8 is provided for inputting to the synchronous switching circuit 8.

In order to monitor the occurrence of a failure in the protection line 200, a pilot generation circuit 9 is provided on the transmitting side and a pilot detection circuit IO is provided on the receiving side. Transmission side switching device 11 for switching signals. Reception code conversion circuit 6.6a
A receiving side switching device 12 is provided for switching between a protection line side signal and a working line signal outputted from the receiver.

In the above line switching device, when the working line lOO is selected, on the protection line 200, the pilot signal output from the pilot generation circuit 9 is transmitted to the transmitting side switching device 11, the transmitting code converting circuit 2a, the transmitting processing circuit 3a, the frame synchronization circuit 4a, the received signal processing circuit 5a, the distribution circuit 7, and the receiving side switch 12, and finally input to the pilot detection circuit IO. therefore,
By detecting this pilot signal, failures in the protection line are detected and line quality is monitored.

[Problems to be Solved] However, in the conventional line switching device described above, since no pilot signal is flowing through the distribution route from the distribution circuit 7 to the synchronous switching circuit 8, there is a problem in that failures in the distribution route cannot be detected. there were.

Therefore, if a fault occurs in the distribution route from the 1 distribution circuit 7 to the synchronous switching circuit 8, the working line signal from the transmission side branch circuit 1 is transferred to the protection line 200 by switching the transmission side switching device 11. However, the protection line 200 will not be connected.

The present invention has been made in view of the above problems, and its object is to provide a line switching device that can detect failures in one branch route and completely monitor backup lines.

[Means for solving Problem B] In order to achieve the above object, the present invention includes a distribution circuit that distributes a signal from a protection line to the working line side, and a synchronous switching circuit that switches between the protection line and the working line. In a line switching device for relieving a line with a backup line, there is a branch circuit that branches the signal before the synchronous switching circuit into two directions, and a signal from this branch circuit or a signal from the distribution circuit is selected. and a fault detector connected to the synchronous switching circuit and receiving the output from the monitoring switching circuit to detect a fault in the protection line from the distribution circuit to the synchronous switching circuit. This is the configuration.

[Function] According to the above configuration, the signal of the working line on the receiving side is branched by the branch circuit and output to the monitoring switching device, and by switching the monitoring switching device, the branch signal is connected to the working line side. synchronous switching circuit. The branch signal input to this synchronous switching circuit is then input to a fault detector before the in-circuit changeover switch, and the line quality of the distribution route is determined by this fault detector.

[Example] An example of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a circuit block diagram of the line switching device according to the embodiment, and the circuit from the sending side branch circuit l to the receiving side switching device 12 is the same as that in FIG. 2. .

A characteristic feature of the present invention is that the quality of the backup line of the 1-distribution route is monitored, and for this purpose, a branch circuit 13 is provided between the received signal processing circuit 5 and the synchronization switching circuit 8 in the 1-distribution circuit. 7 and the synchronous switching circuit 8, a monitoring switching device 14 is installed near the distribution circuit 7, and the synchronous switching circuit 8
A fault detector 15 is connected to.

The branch circuit 13 branches the signal of the working line 100 and supplies it to the monitoring switch 14, and the monitoring switch 14 outputs the branch signal to the synchronous switching circuit 8 while the working line is in use. Switch. In addition, the fault detector 15
In the embodiment, it is connected to the protection line side before the changeover switch in the synchronous switching circuit 8, and it is possible to input the above-mentioned branch signal and detect a fault in the line.

According to the above configuration, the synchronous switching circuit 8
When 00 is selected, a branch signal, which is a signal of the working line 100 branched from the 1-branch circuit 13, is input to the synchronous switching circuit 8 via the monitoring switch 14. The branch signal input to the synchronous switching circuit 8 is supplied to the fault detector 15 before the changeover switch, and the fault detector 15 detects a fault using the branch signal (working line signal).

In this case, since the monitoring switch 14 is provided close to the distribution circuit 7, the quality of the backup line on the distribution route from the distribution circuit 7 to the synchronous switching circuit 8 can be monitored by the detection by the fault detector 15. .

[Effects of the Invention] As explained above, according to the present invention, a branch circuit is provided in the working line, a monitoring switch is provided between the 1 distribution circuit and the synchronous switching circuit, and the branch signal from the branch circuit is used for monitoring. Since the branch signal is supplied to the synchronous switching circuit via the switch and inputted to the fault detector to detect line failures, it is possible to create a backup distribution route between the distribution circuit and the synchronous switching circuit when selecting the working line. Line quality can be monitored.

Therefore, the quality of the protection line can be completely monitored, and there is an effect that line disconnection can be avoided when selecting the protection line.

[Brief explanation of drawings]

FIG. 1 is a circuit block diagram showing MaJ& of a line switching device according to an embodiment, and FIG. 2 is a circuit block diagram showing the configuration of a slave line switching device. l: Branch circuit 5, 5a: Received signal imaginary circuit 7: Distribution circuit 8: Synchronous switching circuit 9: Pilot generation circuit circuit lO: Pilot detection ll: Transmitting side switching device 12: Receiving side switching device 13: Branch circuit 14: Monitoring switch 15: Fault detector

Claims (1)

[Claims] A line switching device for relieving the working line with the protection line, which includes a distribution circuit that distributes signals from the protection line to the working line side and a synchronous switching circuit that switches between the protection line and the working line, the synchronous switching circuit as described above. A branch circuit that branches the previous signal into two directions; a monitoring switch that selects and switches between the signal from this branch circuit and the signal from the distribution circuit; What is claimed is: 1. A line switching device comprising: a failure detector which inputs the output from the synchronous switching circuit and detects a failure in a protection line from the distribution circuit to the synchronous switching circuit.