JPH04138728A - Active and reserve changeover system - Google Patents

Abstract

PURPOSE:To change over the active and the reserve circuit without causing momentary interruption of a data by generating an active/reserve changeover control signal based on a generated reference clock and latching the changeover control signal with the reference clock so as to select the active circuit or the reserve circuit. CONSTITUTION:A timing clock 11 from a unified clock source 2 is fed respectively to a changeover control circuit 1, an active circuit 3 and a reserve circuit 4. When the active/reserve changeover is implemented by a prescribed method, the changeover control circuit 1 generates set signals 12, 14 synchronously with a falling point A of the timing clock 11 to output them to the active circuit 3 and the reserve circuit 4 respectively. The active circuit 3 and the reserve circuit 4 latch the set signals 12, 14 respectively at a succeeding rising point B of the timing clock and the active circuit 3 is switched to the reserve side and the reserve circuit 4 is respectively simultaneously changed to the active side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a working/standby switching circuit for a digital transmission device.

[Conventional technology]

Conventionally, the working/standby switching method of digital transmission equipment that has a fully duplex redundant configuration and switches multiple working/standby circuits at the same time is synchronized with the timing clock provided in the switching control circuit that sends the working/standby switching control signal. A switching signal was generated and sent to multiple working and backup circuits to be switched.

[Problem to be solved by the invention]

In this conventional working/protection switching method, the switching control signal generated by the switching control circuit and the frame synchronization of the data handled by the working/protection circuit are asynchronous, so instantaneous data interruption occurs when switching between the working and protection circuits. There was a drawback.

An object of the present invention is to provide a working/standby switching system that does not cause instantaneous data interruption.

[Means to solve the problem]

The working/protection switching method of the present invention generates a working/backup switching control signal based on the generated reference clock, and latches this switching control signal with the reference clock to switch between the working circuit and the protection circuit. a reference clock generating means for generating a reference clock; a switching control signal generating means for receiving the reference clock outputted by the reference clock generating means and generating a working/standby switching control signal; The circuit includes working/standby switching means that receives the switching control signal and the reference clock, latches the switching control signal using the reference clock, and switches between the working circuit and the standby circuit at that timing.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a time chart showing a switching operation. Current use in Figure 1
In the backup switching method, a switching control circuit 1 outputs a working/standby switching means signal, and a unified clock synchronized with data handled by the working circuit 3 and the protection circuit 4 is used in the switching control circuit 1. Current circuit 3. It consists of a unified clock source 2 that sends out to a backup circuit 4.

Here, it is assumed that the current circuit 3 is switched to the backup circuit and the backup circuit 4 is switched to the current circuit.

In FIG. 2, a timing clock 11 is supplied from a unified clock source 2 to a switching control circuit 1. It is supplied to the current circuit 3 and the backup circuit 4, respectively. When the working/standby switching operation is performed in a predetermined manner, the switching control circuit 1 switches to the timing clock 1.
Set signals 12 and 14 synchronized with falling point A of 1
is generated and output to the current circuit 3 and backup circuit 4, respectively. The current circuit 3 and the backup circuit 4 receive set signals 12 and 14 at the next rising edge of the timing clock at point B.
are latched, and the working circuit 3 is switched to the standby side, and the standby circuit 4 is switched to the working side at the same time.

〔Effect of the invention〕

As explained above, the present invention has the effect that the Mal signal for switching between the working and backup circuits is in the same phase as the frame head of the data handled, so that the switching between the working and backup circuits can be performed without causing a momentary data interruption. be.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG. 2 is a flow chart showing its operation. 1-...Switching control circuit, 2...Unified clock source, 3-...
- Working circuit, 4... Reserve circuit.

Claims (1)

[Claims] 1. In a working/standby switching system for a digital transmission device with a fully duplex redundant configuration, a working/standby switching control signal is generated based on the generated reference clock, and this switching control signal is A working/standby switching method characterized in that the working circuit and the standby circuit are switched by latching the signal with the reference clock. 2. a reference clock generation means for generating a reference clock;
A switching control signal generating means receives a reference clock output from the reference clock generating means and generates a working/standby switching control signal; 2. The working/standby switching system according to claim 1, further comprising working/standby switching means for latching the switching control signal using a clock and switching between the working circuit and the standby circuit at that timing.