JPH0279519A - Line switching circuit in transmission line system - Google Patents

Abstract

PURPOSE:To improve the line utilizing efficiency and to facilitate the maintenance by providing a switch means to each of an active transfer panel and a standby transmission panel and switching the line into the standby line if a fault takes place in the switch means for changeover or the active line. CONSTITUTION:A switch 2 acts like whether or not connecting termination resistors 4, 4'. The termination resistor has, e.g., 75 ohms, which matches the impedance at the transmission panel side. Thus, in this case, the signal is sent not only to the active system but also to the standby system. If a fault of the active system is detected by a panel A, it is informed to panels B, C to switch the switch section 3 of each panel. Since the switch sections 2, 3 are provided to both the active and standby systems, the transmission panel is removed together with the switch sections 2, 3 and the transmission line is not interrupted even in maintenance of the switch section.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 4) Means for solving the problems to be solved by the invention (Figure 1) Working examples (Figure 2) , Fig. 3) Effects of the Invention [Summary] The purpose of this invention is to enable line switching even if a failure occurs not only in the line but also in the switching means itself, regarding a line switching circuit in a transmission line system, and with the aim of making it possible to switch the line not only in the line but also in the switching means itself. A working line connected to this working transmission panel, a spare transmission panel, and a spare line connected to this spare transmission panel are provided,
- In a transmission line system in which signal transmission is performed by switching to the other line when a fault occurs on one line, switching means can be provided on each of the active transmission panel and the backup transmission panel, and each can monitor the status of the other line. The system is configured so that when a failure occurs in the current line or switching means, the line is switched to the backup line.

[Industrial Application Field] The present invention relates to a transmission line system having two transmission panels, a working system and a backup system, and particularly relates to a line switching circuit for switching between the working system and the backup system transmission line.

With the increasing demand for data transmission in recent years, there is a demand for highly reliable transmission line systems.For this reason, a spare transmission panel is provided outside the current transmission panel, and in the event of a failure of the current transmission panel, a backup transmission line system is required. A transmission line system with a switching circuit that switches to the panel is used.

[Conventional technology]

FIG. 4 is an example of a conventional transmission line system having a switching circuit for switching between a working transmission line and a protection transmission line.

In the figure, numerals 41 and 44 are switching devices, which switch between two lines, a working line and a protection line, which will be explained later. Reference numerals 42 and 43 are transmission devices, which include active transmission panels 4G and 47, and backup transmission panels 46' and 4, respectively.
Contains 7'.

Reference numerals 4B and 48' indicate transmission lines, which constitute a working transmission line and a protection transmission line, respectively.

The switching circuits 41 and 42 each have contacts a and b, and when some kind of failure occurs in the current line, by switching these, the transmission panel is switched from the current system to the pre-01 system.

This makes it possible to construct a highly reliable transmission line system.

[Problem to be Solved by the Invention] According to the example of Tsuchiya mentioned in (T) above, even if one transmission panel fails, a spare transmission panel is prepared, so the transmission panel can be changed to -rD;η. It can be switched, and reliability can be increased accordingly.

However, if the transmission line switching device itself malfunctions, the transmission signal will not be transmitted to the transmission panel even if the transmission panel is normal, and signal transmission will become impossible until the switching device itself is repaired. It had

[Means to solve the problem]

No. 11a is a diagram of the principle of this invention. In Figure 1, A, [3, A', B' are transmission panels;
constitutes a working transmission line together with transmission line 5,
A' and 13' constitute a backup transmission line together with the transmission line 5'. The transmission panels A, B, A', B' are each provided with a transmission circuit 1, and are further provided with a switch section 2.3 according to the invention.

The switch unit 2 is a switch for terminating or not terminating a manually input transmission signal line, and the switch unit 3 is a switch for outputting or not outputting a received transmission signal. Furthermore, each of the panels A, B, A', and B' is provided with a monitoring section (not shown), which constantly monitors the status of the current and reserved lines through the signal lines 6, 8, and 9.

[Function] In the present invention, the switch unit 2.3 for line switching is housed in each of the working and standby transmission panels, and each panel constantly monitors the line status of the working and standby lines.

Normally, the signal input end is terminated at the working panel, and the output is the signal received by the working panel. However, if some kind of failure occurs in the working system such as the working panel, it becomes a switching signal, and the signal is sent to the spare panel. The signal line is terminated and the receiving system switches to the signal received in reserve.

Therefore, when switching signals, only the backup system transmission equipment is required, and the active system equipment can be freely inserted and removed.
During this time, you can perform maintenance on the failed panel.

〔Example〕

FIG. 2 is an embodiment of the present invention. The same parts as the principle diagram shown in Figure 1 are given the same numbers, so
A detailed explanation of this part will be omitted.

In this embodiment, the switch 2 is configured to determine whether or not to connect the terminating resistor 4.4'. The terminating resistor is, for example, 75
Ω, thereby achieving impedance matching with the transmission panel side.

Therefore, in this case, the signal is transmitted not only to the working system but also to the protection system. The switch unit 3 determines whether to use the active system or the backup system.

Now, when the occurrence of a fault in the active system is detected on panel A, this is transmitted to panels B and C, and the switch units 3 of each panel are switched.

A signal notifying the occurrence of a failure can be sent together with the data signal by providing a bit for this purpose in the data signal, for example.

In this invention, since the switch sections 2.3 are provided in both the active system and the standby system, the transmission panel including the switch sections 2.3 can be removed, and the transmission line can be removed even during maintenance of the switch sections. Never give up.

Dotted lines in FIG. 2 indicate signal transmission paths in the active system.

FIG. 3 shows a state where the active system is switched to the standby system, and the V! of panel A' is shown. The end low resistance 4 is grounded, and the switch section 3 of panel B' is closed. The signal is the third
The data will be transmitted according to the dotted lines in the figure.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to switch between the active system and the backup system even in the event of a failure in the changeover switch section of the transmission line that has two systems, the active system and the backup system, and moreover, the transmission line The transmission line will not be interrupted even during a failure or maintenance of the transmission panel.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention in detail, FIG. 2 is a diagram for explaining the invention in detail, and FIG. 3 is a diagram showing a state in which the switch section is switched in an embodiment of the present invention. , FIG. 4 is a diagram showing a conventional example. 1--Transmission circuit, 2.3-Switch section, 4-Terminal resistor, 5.5'-Transmission line, 6.7.8.9-Switching control signal.

Claims (1)

[Claims] (1) A working transmission panel, a working line connected to this working transmission panel, a spare transmission panel, and a spare line connected to this spare transmission panel are installed, and when a failure occurs in one line, In a transmission line system in which signal transmission is performed by switching to the other line, switch means (2) and (3) are provided on each of the working transmission panel and the standby transmission panel, and the status of the other line can be monitored. A line switching circuit in a transmission line system, characterized in that when a failure occurs in a line or switching means, the line is switched to a spare line.