JPS63105535A - Duplex circuit system - Google Patents

Abstract

PURPOSE:To decrease the number of lines required for confounding paths by inserting a tri-state buffer to the confounding path in a changeover means confounding an active system and a standby system. CONSTITUTION:The tri-state buffers 10, 11 in the active system 1 and the standby system 2 are connected respectively to the sending end of pre-stage circuits 3, 4 each and controlled by a switching control signal 7. Outputs of the tri-state buffers 10, 11 are connected multiply and given to switching circuits 8, 9 respectively via a path 12, where a signal flows bidirectionally. Then the output of the tri-state buffer 10 of the active side is enabled when the switching circuits 8, 9 select and pass the signal from the pre-stage circuit 3 of the active system in the tri-state buffers 10, 11 and the output of the tri-state buffer 11 of the standby system is brought into a high impedance. In this case, the bidirectional confounding path 12 is connected from the active to the standby system.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to active/backup switching means for communication equipment.

〔overview〕

The present invention reduces the number of lines required by the confounding path by inserting a 3-state buffer into the confounding path in a switching means that removes the confounding of the working system and the backup system in a duplex configuration of the working system and the backup system. It was made so that it could be done.

[Conventional technology]

An example of the configuration of a conventional switching system of this type is shown in FIG.

This conventional system includes front-stage circuits 16 and 17 and rear-stage circuits 18 and 19 of each of the active system 14 and the backup system 15.
It is inserted between the front stage circuits 16 and 17 and the rear stage circuits 18 and 19, and inputs the output signals from the front stage circuits 16 and 17 and the output signal of the other party which has been deconfounded. A switching control signal 20 is issued to each switching circuit 21 and 22 based on fault information from the switching circuits 21 and 22 that switch to and return to the normal system, and the front stage circuits 16 and 17 of the active system 14 and standby system 15. The switching control signal generating circuit 23 was configured to perform the following steps.

[Problem that the invention seeks to solve]

In such conventional switching means, from the active system to the standby system,
In addition, it is necessary to provide separate signal paths from the backup system to the active system, so in equipment with a large number of signal lines that require switching, the amount of cables required to achieve interlacing becomes a major burden on the equipment configuration. There are drawbacks.

The present invention aims to eliminate such drawbacks and to provide a duplex circuit system that can reduce the amount of cables required for interlacing.

[Means for solving problems]

The present invention provides a first signal circuit that sends out a first signal, a second signal circuit that sends out a second signal equal to the first signal, and a first signal circuit that receives the first and second signals. In a duplex circuit system comprising a first switching circuit and a second switching circuit that select one of the switching circuits, and a control circuit that provides a switching control signal to the first and second switching circuits, inputting the first signal,
A first 3-state buffer whose impedance is controlled by a switching control signal and provides an output to one of the switching circuits, and a second signal is input to which the impedance is controlled by the switching control signal and the output is sent to the switching circuit. a second three-state buffer that provides a first signal to one of the switching circuits; a second electrical path that provides a second signal to the other switching circuit; The present invention is characterized by comprising a third electric path that intertwines the output of the first three-state buffer and the output of the second three-state buffer.

[Effect]

Normally, the output of the first signal circuit goes through the first switching circuit,
Also, assuming that the output of the second signal circuit passes through the second switching circuit, when the first signal circuit becomes in a fault state, the 3-state buffer related to the second signal circuit becomes low impedance, and the output of the second signal circuit reaches the first switching circuit via this three-state buffer. At this time, the three-state buffer associated with the first signal circuit is controlled to be high impedance and does not allow any signal to pass through. That is, the signals passing through the two switching circuits are the outputs of the second signal circuit.

〔Example〕

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a block diagram showing the configuration of this embodiment.

First, the configuration of this embodiment will be explained based on FIG. This embodiment includes an active system 1, a standby system 2, and a switching control signal generation circuit 13, where the active system 1 includes a front-stage circuit 3, a rear-stage circuit 5, a switching circuit 8, and a three-state buffer. 1
Further, the standby system 2 includes a front-stage circuit 4, a rear-stage circuit 6, a switching circuit 9, and a three-state buffer 11.

Next, the operation of this embodiment will be explained based on FIG.

Switching circuits 8 and 9 are inserted between the front stage circuits 3 and 4 and the rear stage circuits 5 and 6 of each of the active system 1 and the backup system 2, and remove confounds with the output signals from the respective front stage circuits 3 and 4. The system inputs the output signal of the other system, and switches to and returns to the normal system based on the switching control signal 7. The 3-state buffers 10 and 11 are connected to the transmitting ends of the respective front-stage circuits 3 and 4, and are controlled by the switching control signal 7.

The outputs of the respective three-state buffers 10 and 11 are multi-connected and input to the respective switching circuits 8 and 9 via intertwined paths 12 through which signals flow in both directions. The switching control signal generation circuit 13 collects fault information of the preceding stage circuits 3 and 4, and determines whether the switching side? Issue H* No. 7. In addition, when the switching circuits 8 and 9 select and pass the signal from the currently used previous stage circuit 3, the 3-state buffers 10 and 11 enable the output of the currently used 3-state buffer 10, The output of the 3-state buffer 11 on the standby side is brought into a high impedance state. At this time, the bidirectional intertwined path 12 is the 0th order flowing from the working to the standby, and the switching circuit 8
and 9 selects and passes the signal from the preliminary front stage circuit 4, the output of the 3-state buffer 11 on the auxiliary side is enabled for output, and the 3-state buffer 11 on the active side
0 output to high impedance state. At this time, the bidirectional intertwined path 12 flows from the standby to the active path.

〔Effect of the invention〕

As explained above, in the present invention, a 3-state buffer is provided at each end of the confounding transmission, so that the confounding route can be made bidirectional. This has the effect of reducing the number of signal lines to one half compared to the case where the signal lines are provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. FIG. 2 is a block diagram showing the configuration of a conventional example. 1.14... Active system, 2.15... Backup system, 3.4
．． 16.17--Previous stage circuit, 5.6.18.19...
・Late stage circuit, 7.20...Switching control signal, 8.9.2
1.22... Switching circuit, 10.11... 3-state buffer, 12... Confounding path, 13.23... Switching control signal generation circuit.

Claims (1)

[Claims] (1) A first signal circuit (3) that sends out a first signal, a second signal circuit (4) that sends out a second signal equal to this first signal, and a A duplex device comprising a first switching circuit (8) and a second switching circuit (9) for inputting the input signal and selecting one of them, and a control circuit (13) for giving a switching control signal to the first and second switching circuits. In the circuit system, a first 3-state buffer (10) is inputted with a first signal, the impedance of which is controlled by a switching control signal, and provides an output to one of the switching circuits, and a second signal is inputted; a second three-state buffer (11) whose impedance is controlled by a switching control signal and provides an output to the other of the switching circuits; a first electric line (25) that provides a first signal to one of the switching circuits; , a second electric line (
26), and a third electric path (12) that intertwines the output of the first 3-state buffer and the output of the second 3-state buffer.
A redundant circuit system characterized by the following.