JPH0383430A - Monitoring system for multiplexer - Google Patents

Abstract

PURPOSE:To execute the operation of switching from a living multiplexer to a spare multiplexer without fail by providing a deciding line to decide whether a line is connected or not to a branching circuit to branch a test signal from the living multiplexer to the spare multiplexer. CONSTITUTION:A low-order group line L11 is branched, connected by high monitor in a branching circuit 4 and applied to one input of a testing device 3. On the other hand, a high-order group line H1 is connected through the branching circuit 4 samely as a high-order group line H4 in the spare multiplexer 2. The low-order group line L41 of the spare multiplexer 2 corresponding to the L11 is connected to the other input of the testing device. Accordingly, the low-order group line signal of the L11 in the living multiplexer can be obtained even in the low-order group line L41. By comparing and collating these two signals in a comparing part CMP, it is decided whether multiplexing processing concerning the low-order group line L11 is normal or not. Accordingly, there is no miss in switching from the living multiplexer to the spare multiplexer.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention provides a multiplexer in which a backup multiplexer in a standby state monitors whether or not the operation of a multiplexer in an active state is normal. This relates to a system for monitoring equipment.

[Conventional technology]

The conventional monitoring method for this type of equipment is
As disclosed in Japanese Patent No. 190736, the operation of the active multiplex device is monitored by a standby device and a test device that are in an idle state.

In this case, the test signal from the working multiplexer is branched and added to the backup multiplexer, and the signals to be compared from each of the working multiplexer and the backup equipment are added to the test equipment and compared and verified. ′! The operating state at position A is determined.

[Problem to be solved by the invention]

Up to now, the operating state of the current multiplexer has been determined by comparing and collating the low-order inter-group line signals in the current and backup windings, and using the results of the comparison and verification.

If an abnormality occurs in the active multiplexer, the active multiplexer is switched to the standby multiplexer, but normal judgment is made based on the results of the comparison and verification.

Here, the input/output of the active multiplexer is connected to the external line, but if, for example, the output line of the higher order group is disconnected due to some abnormality and is not connected to the line, the multiplexer will Matching between circuit lines becomes impossible, and the output waveform of the current multiplexer is distorted. Since this waveform is applied to the backup multiplexer, the comparison and verification becomes abnormal, and there is a problem in that the system is switched to the backup multiplexer as if a device error had occurred.

It is an object of the present invention to provide a monitoring system that eliminates the switching from a working multiplexer to a protection multiplexer.

[Means for solving the problem] In order to achieve the above object, a judgment circuit is provided for determining whether or not a line is connected to a branch circuit that branches a test signal from a working multiplexer to a standby multiplexer. This was realized in a similar way.

[Effect]

The test signal is branched from the working multiplexer and added to the backup multiplexer, but the line to the working multiplexer is connected to this branch circuit at t2.
By adding a determination circuit that determines whether or not the line is connected, the connection state of the line can be determined.

By adding the output of this judgment circuit to the comparison and verification circuit of the test equipment, the comparison and verification results can be made valid only when the line is connected. Malfunctions can be prevented.

〔Example〕

The present invention will be explained below with reference to FIG. 1, taking a stuff multiplexing device as an example.

FIG. 1 shows an example of a connection state when one of a plurality of active multiplex devices is monitored by a test device 3 via a standby multiplex device 2. In FIG.

If a failure of some kind occurs in any of the multiple active multiplexers, the multiplexer associated with the failure is replaced with a standby multiplexer 2 of the same configuration.
During normal times, this backup multiplexer 2 is used to monitor the operation of each of the active multiplexers 1.

Now, in the current multiplex converter 1, the low-order group line L lt
'-L PCM signal from each L3 (e.g. 32°06
4M41z) is bipolar. After being converted into a unipolar signal by the unipolar switching circuit BU.

The signal is multiplexed by a multiplexing unit MUX with a built-in buffer circuit, and is then converted into a unipolar high-order group line signal (for example, 97728MI(z)) and sent onto the high-order inter-group line I11 via a bipolar conversion circuit UB.

- The next group line signal is received on H8, and conversely to the above, it is demultiplexed by the demultiplexer DMUX, and the high order group signal is sent to the low order group line L! A low-order group line signal corresponding to L''' L mm is separated.

The same applies to other working multiplexing devices, and the same applies when the backup multiplexing device 2 is used as a working multiplexing device.

The general operation processing in the current multiplexer 1 has been explained above, but for example, whether or not to multiplex the low-order group line signal corresponding to the low-order inter-group line Ltt is determined as follows. are now being monitored.

That is, for the low-order group line L+t+, the high monitor is connected in the branch circuit 4 as shown by the dotted line, and in addition to one input of the test device 3, for the -power line group line 1 (, Similarly, it is connected to the high-order inter-group IA H4 in the backup multiplexer 2 via the branch circuit 4. Also, the low-order group line L 4 L of the backup multiplexer 2 corresponding to □ is connected to the other one of the test equipment. Connect to the input.By connecting in this way, the low-order group line signal of L1□ of the current multiplexer becomes the low-order
can also be obtained on line L4L, and these two signals are connected to each input of test equipment 3, with a ratio of 1
If you compare and match with shark part CMP, the difference between lower order groups is 1 dA L 1
It is determined whether the multiplexing process for t is normal or not, but in the branch circuit 4, a determination circuit output for determining the connection state of the line is applied to the comparison unit CMP in the test device. Therefore, the configuration is such that comparison and verification are enabled when the connection status is normal. The current multiplex'! If the switch is made from the A location to the standby multiplex device, there will be no possibility of an erroneous switching operation.

Although the monitoring of the multiplexing section has been described above in detail, the same applies to the demultiplexing section.

The determination circuit that determines the connection status of the line built in the branch circuit can be made by detecting that the output level is large when matching cannot be achieved, and the output level detection circuit can be implemented using a known circuit. A 41iI board can be created with a simple circuit.

〔Effect of the invention〕

As described above, according to the present invention, by providing a relatively simple determination circuit, the switching operation from the active multiplexer to the standby multiplexer can be reliably realized.

[Brief explanation of drawings]

FIG. 1 shows an example of a connection state when a working multiplex device is monitored by a test device via a standby multiplex device. Engineering: Current multiplexer, 2: Backup multiplexer, 3: Trial! gA device, 4... Branch device, BU... Bipolar/unipolar conversion circuit, UB...
- Unipolar-Hohler conversion circuit, MUX...multiplexing section, DMUX...demultiplexing section. CMP...Comparison and verification section.

Claims (1)

[Claims] 1. Equipped with a working multiplexer that demultiplexes signals of a plurality of low-order group lines and multiplexes them into signals of a high-order group line, and a backup multiplexer and a test device having the same configuration as the multiplexer,
selectively branching and connecting the low-order group line of the working multiplexer and the low-order group line of the protection multiplexer to the test equipment, and also the high-order group line of the working multiplexer and the high-order group line of the protection multiplexer; In a monitoring method for a multiplex converter that selectively branches and connects and compares and checks signals of a low-order group line in the test equipment by a comparison unit, from the current multiplexer,
As a circuit configuration of a branch circuit for branching low-order group and high-order group signals to a backup multiplexer as test signals, this is used to determine whether or not the used line is connected to both the low-order group and high-order group of the active multiplexer. A multiplex device monitoring system characterized in that a judgment circuit is provided in a branch circuit.