JPS6232741A - Loopback control system for loop transmission equipment - Google Patents

Abstract

PURPOSE:To prevent the titled system from breaking down by looping back a remote station cascade-connected with a reverse circular line from its adjacent remote station when the former remote station detects the abnormality of the transmission signal. CONSTITUTION:The remote stations 2-6 are connected to a synchronizing station 1 through reverse circular line 7, 8 to transmit signals. When lines 7, 8 are failed at points 9A, 9B, the line 7, 8 are looped back. If the lines 7, 8 are disconnected at points (a), (b), no input is applied to repeating parts 31, 42 in the remote stations 3, 4 and synchronization error and carrier disconnection are generated in respective systems, so that repeaters 41, 51, 61 and 32, 22 are turned to the error state. By-pass control parts built in the remote stations 3, 4 are actuated to disconnect the remote stations 3, 4 from the circuits and the line 7, 8 are looped back by the remote stations 2, 5. Consequently, the system can be prevented from breaking down.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application'] The present invention relates to a loopback control method for a loop transmission device.

[Conventional technology]

FIG. 2 is a block diagram of a conventional loop transmission device 69. In the figure, 1 is a synchronization station and 2 to 6 HIJ mote stations. 7 is an I-system transmission line, 8 is a II-system transmission line, and 9 A+ 9 B is a disconnection location.

The synchronization station 1 is a synchronization control section 11 of the I non-transmission path 7.
, a synchronization control section 12 for the transmission line 8, and a monitoring control section 10 for each transmission line 7.8.

Each of the remote stations 2 to 6 has one relay section 21.31.41.51.61 of the I non-transmission path 7 and one relay section 22.32.42, 52.62 of the i-system transmission path 8. Configured with the necessary features.

FIG. 3 is a detailed diagram of the remote station, taking remote station 4 as an example, and receivers 411, 4.
12, drivers 421, 422. Selector 431, 43
2 and a loopback control section 43.

Next, the operation will be explained. The operation when disconnection points 9A and 9B shown by x marks in FIG. 2 occur will be described.

In the mountain transmission line 7, the relay section 4 of the remote station 4
When the station 1 detects a carrier disconnection, the information is passed through the remote stations 5 and 6 and detected as a synchronization error by the synchronization control section 11 of the synchronization station 1. On the other hand, regarding the n-system transmission line 8 as well.

Similarly, when the relay section 32 of the remote station 3 detects the carrier lfr, the information is transmitted via the remote station 2 and detected as a synchronization error by the synchronization control section 12 of the synchronization station 1.

When the synchronization station 1 detects a synchronization error in both the mountain transmission line 7 and the mountain transmission line 8, the supervisory control unit 10 transmits a loopback command to all remote stations 2 to 6.

Next, the operation when the remote station receives a loopback command will be explained with reference to FIG. At the remote station, the roof hack command t, the loopback control unit 4
I pass with 3. At that time, if carrier disconnection is detected in the receivers 411 and 412 of the mountain transmission line 7 or the n-line transmission line 8, the loopback control unit 43 outputs a switching command to the selectors 431 and 432. Then, the selectors 431 and 432 select the B side, and the received signal on the mountain transmission line 7 is sent to the receiver 411 and the selector 43.
2. The receiving layer signal of the mountain transmission line 8 is sent to the mountain transmission line 8 via the driver 422, and is sent to the receiver 412, selector 431.
Each detour is made to the 1-system transmission line 7 via the driver 421.

The above operation is performed only at remote stations 4 and 3 that have detected carrier disconnection, and signals are not diverted from other remote stations because they have not detected carrier disconnection. In this way, a loop bank is established.

[Problem that the invention seeks to solve]

Since the loopback control method of the conventional loop transmission device is performed as described above, for example, as shown in points a and b in FIG.
In the case of a disconnection at a location, the loopback command from the synchronization station 1 would not reach the remote stations 3 and 4, resulting in a problem that the loopback could not be established and the entire system would go down.

This invention was made to solve the above-mentioned problem, and by making it possible to establish a loopback even in the event of a disconnection at different points between remote stations, it is possible to prevent the entire system from going down. The purpose of this study is to obtain a loopback control method for a loop transmission device that does not have a loop transmission device.

[Means for solving the problem] □The loopback control method of the loop transmission device according to the present invention is capable of detecting an abnormality (synchronization error or carrier disconnection) in both the i-system transmission line and the ■-system transmission line at the remote station. etc. is detected,
It is designed to degenerate by bypassing the image transmission path.

[For production]

In the loopback control method of the loop transmission device in this invention, a remote station that detects an abnormality in both the I system transmission line and the mountain transmission line bypasses each transmission line and degenerates. Loopback is established.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 411.412, 421.422°4
31, 432, and 43 are the same as the conventional ones, and 44 is a bypass control unit that detects an abnormality in both the mountain transmission lines 7 and 8 and outputs a bypass command.
Reference numerals 45 and 46 designate bypass switches that disconnect the remote station from the loop of image transmission lines 7 and 8 in response to this bypass command.

Next, its operation will be explained. Points a and b in Figure 2
When a disconnection occurs at two points, the bypass control units 44 of the remote stations 3 and 4 detect a one-system synchronization error, a carrier disconnection in the other system, or a two-system abnormality. That is, due to the disconnection at point a of the 1st transmission line 7, the drying station 3
Then, the carrier from the HIJ mote station 2 is no longer input, and the carrier of the mountain transmission line 7 is cut off. Also,
The remote stations 4, 5, and 6 no longer receive the synchronization word from the synchronization station 1, and a synchronization error occurs in the n-system transmission line 7, respectively. Similarly, a disconnection at point b of the n-system transmission line 8 causes a carrier disconnection on the n-system transmission line 8 at the remote station 4, and a synchronization error on the (2)-system transmission line 8 at the remote stations 2 and 3, respectively. Therefore, in remote stations 3 and 4, one system synchronization error and the other system carrier disconnection occur, respectively. When this state is detected, the bypass control section 44 outputs a bypass command to the bypass switches 45 and 46. Bypass switch 45.46 is
The state shown by the dotted line in Figure 1 is reached, and the remote station 3,
4 is separated from the loop.

As a result of the above operation, carrier disconnection is detected at the receiving section of the remote station 2 and the receiving section of the remote station 5, respectively. On the other hand, since the loopback command from synchronization station 1 has reached remote stations 2 and 5, loopback is established.

In the above embodiment, relays are used as the bypass switches 45 and 46, but optical switches may be used in the case of optical fiber transmission.

In addition, although only the case of abnormality in both systems was mentioned as the cause of commands to the bypass switch, other factors such as remote station abnormality, power supply abnormality, command from manual switch, etc.
It may also include commands from the synchronization station.

〔Effect of the invention〕

As described above, according to the present invention, only the remote station that detects an abnormality in both systems is degenerated and a loopback is established with the remote station adjacent to the remote station, so that the entire system does not go down. This has the effect of increasing the system operating rate.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a loopback and bypass control section used in a loopback control method of a loop transmission device according to an embodiment of the present invention, Fig. 2 is a block diagram of a loop transmission system, and Fig. 3 is a block diagram of a conventional loopback control system. It is a block diagram of a control part. 1 is a synchronization station, 2 to 6 are remote stations, 7 is an I system transmission line, 8 is a ■ system transmission line, and 9A. 9B, Todoroki, b is the disconnection point, 10 is the monitoring control section, 11゜1
2 is a synchronous control unit, 21.22.31,32,41°42
．． 51.52.81.82 is a relay unit, 43 is a loopback control unit, 44 is a bypass control g, 45°46 is a bypass switch, 411.412U receiver, 421.42
2 is a driver, 431.432 is a selector. In addition, in FIG. 1, the same reference numerals indicate the same or equivalent parts. Patent applicant Mitsubishi Electric Co., Ltd. agent Patent attorney 1) Hiroshi Sawa (and 2 others) Amendment to sub-procedure (voluntary) Date: 1985♀11

Claims (1)

[Claims] In a loop transmission device in which a synchronization station having a supervisory control unit and a plurality of remote stations that perform loopback control based on loopback commands from the supervisory control unit are cascaded through an I-system transmission line and a II-system transmission line. In a loopback control method of a loop transmission device that performs loopback control when the transmission line at an arbitrary position is disconnected, an abnormality, etc. is detected in both the transmission lines of the I-system transmission line and the II-system transmission line. A loopback control method for a loop transmission device, characterized in that the remote station is bypassed from each transmission path to establish a loopback at the remote station adjacent to the remote station.