JPH0229260B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a station device for a duplex ring type transmission system having a loop back function.

[Prior art]

Conventionally, there has been a device of this type as shown in FIG. In the figure, 1 is a synchronization station (second station) of a ring type transmission system, 2,
3,...n are remote stations (first station), LL and LR are transmission lines connecting the synchronization station 1 and remote stations 2 to n with the same configuration in a series ring, respectively.
Configure the system.

Synchronization station 1 is synchronization section 1 of transmission line LL.
2. Transmission line LR synchronization unit 13 and monitoring control unit 11
It consists of Further, the remote station 2 has a configuration as shown in FIG. 2, and the remote stations 3 to n also have a similar configuration. And remote station 2~
For example, the station n has a self-running clock and is of a regenerative relay type that reproduces data from the received signal and transmits this data again to the next station.

Here, an example of the operation when a disconnection occurs at a location marked with an x will be described. In the system, remote station 3
The relay section 32 detects the absence of the carrier. Then, in the case of a regenerative repeating station, the remote station 3 transmits the carrier of abnormal data to the next station. A carrier with abnormal data reaches the synchronization section 12 of the synchronization station 1 via the relay section 22 of the remote station 2, where it is detected as a synchronization error.

Similarly, the relay section 43 of the remote station 4 detects the absence of a carrier,
The carrier with incorrect data is sent to synchronization station 1 via remote stations 5 and n.
, and a synchronization error is detected here.

, when a synchronization error occurs in the system, the supervisory control unit 1
1 is activated, and the monitoring control unit 11 controls all remote
Loop back control commands COMA and COMB (shown in FIG. 3) are transmitted to stations 2 to n.

FIG. 2 is a block diagram showing the configuration of the remote station 2. As shown in FIG. In the figure, RCA and RCB are receivers for transmission lines LL and LR, SA and SB are loop back relay switches, and TA and TB are transmitters. At remote station 2, the loop back control commands COMA and COMB are sent to the receiver RCA,
The command receiving unit 21 receives the command via the RCB.
The command detection unit CDB shown in Figure 3 is a loop
Upon detection of the back control command COMB, the detection output CDOB is input to the flip-flop FFB and the timer circuit TMB. This allows the flip
Flop FFB is set and loop back control signal LBB is output to toggle switch SA. Timer TMB is a loop back control command
Since it outputs high after time T from activation of COMB, if the carrier detection signal CYA of the system is present at that time, AND gate AB opens and the flip
The flop FFB is reset and the loop back is released (see Figure 4).

The behavior of the system is similar to that of the system.
In Figure 3, CYA is the carrier detection signal, AA is the AND gate, TMA is the timer, and FFA is the flip signal.
The flop, CDA, is a command detection section and generates a detection output CDOB. COMA is a loop back control command, and LBA is a loop back control signal.

Through this operation, a final loop back is established at remote stations 3 and 4,
Ring reconfiguration is established.

Conventional station devices are configured as described above, so even if the wire breaks again after entering the loop-back state (in most cases, the wire will not break due to an intentional wire breakage when repairing the cause of the loop-back, etc.). ), it is difficult to start the loop back again because a joint error does not occur in both systems, and normally the entire system will be brought down.

In addition, in conventional station devices, each station is once looped back during the switching operation to loop back, so the system may become pseudo-normal, which has the disadvantage of making it difficult to determine whether loop back has been established. It was hot.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional system. During loop back, the loop back control command is constantly sent to all remote stations, and each remote station By executing loop back when the loop back control command is present and the carrier is absent, the loop
It is an object of the present invention to provide a station device for a duplex ring type transmission system that can easily perform re-loop-back in a back-up state and can reliably determine whether loop-back is established.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. In Figure 5, the same symbols as in Figure 3 indicate the same parts, ANA and ANB are AND gates, IA,
IB is an integrating circuit that generates integral outputs IOA and IOB.

The overall configuration of the ring and the configuration of remote stations 2-n are shown in FIGS. 1 and 2.

If a disconnection occurs at the location marked with an x in FIG. 1, the synchronization station 1 detects a synchronization error in both systems and activates the supervisory control section 11.

Command receiving unit 2 of remote station 2
1, the command detection unit CDB receives a continuous loop back control command COMB from the transmission line LR.
The detection output CDOB is generated (see Figure 6). At this time, the regenerative relay type remote station 3
Since a carrier with abnormal data is being sent from the system, the system's carrier detection signal CYA is present and the integral output IOA is high, so the AND gate ANB is closed and the loop back control signal LBB is output. There isn't.

On the other hand, at remote stations 3 and 4 related to the disconnection, the carrier detection signal CYA (or
CYB), so the AND gate ANB
(or ANA) is opened and the loop back control signal LBB (or LBA) is output.

Therefore, since the remote stations 2, 5, and n detect the carrier detection signal CYA or (CYB), loop back is not performed, but is performed only at the remote stations 3 and 4 related to the disconnection. As a result, a pseudo loop does not occur, and synchronization station 1
It is possible to easily determine whether a buck has been established.

In addition, the loop cross control command COMA,
Since the COBM detection outputs CDOA and CDOB are constantly output, for example, in the loop back state shown in Figure 1, the transmission line between remote stations 2 and 3
When LL and LR are removed, the relay section 22 of the remote station 2 immediately outputs the carrier detection signals CYA,
Loop back control can be performed by pulling CYB low.

In the above embodiment, whether or not to execute loop back is determined based on the presence or absence of a carrier detection signal, but this is not limited to the detection of a carrier detection signal as long as it indicates a break in the transmission line. Furthermore, although the loop/back switching is shown as a relay contact, even if it is a semiconductor switch, the same effect as in the above embodiment can be achieved.

〔Effect of the invention〕

As described above, according to the present invention, the loop-back control circuit can be simplified, automatic re-loop-back can be performed immediately, and it is possible to easily determine whether loop-back is established.

[Brief explanation of drawings]

Figure 1 is a connection diagram of a duplex ring type transmission system, Figure 2 is a block diagram of a relay transmission section of a remote station, Figure 3 is a block diagram of a conventional remote station command reception section, and Figure 3 is a block diagram of a conventional remote station command reception section. 4 is a timing diagram showing the operation of the command receiving section in FIG. 3, FIG. 5 is a block diagram of the command receiving section according to an embodiment of the present invention, and FIG. 6 is a timing diagram showing the operation of the command receiving section in FIG. 5. FIG. 1...Synchronization station, 2,3-n...Remote station, 21...Command receiving unit,
CDA, CDB...Command detection unit, IA, IB...Integrator, SA, SB...Switch. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A duplex ring type transmission system in which a plurality of regenerative repeater first stations that transmit and receive data via a duplex ring type transmission path and a second station for synchronizing the first stations are connected in series. In the above, the second station includes a monitoring control unit that continuously sends out a command for loop-back to the transmission path, and each of the first stations detects the command from the transmission path, and the first station detects the command from the transmission path, and A redundant system characterized by comprising a command receiving section that loops back the system that received the command when the carrier for conveying the data is not received from a system different from the system that received the command. Ring type transmission system.