JPH01151338A - System for switching system of digital line termination controller - Google Patents

Abstract

PURPOSE:To shorten a signal stop time by switching a system from a spare system to a normal system autonomously not by a system switching command from a host device when the fault of power disconnection is generated in the normal system. CONSTITUTION:A digital line termination controller is provided with another system monitoring lines 5 and 6 to monitor another system mutually, and its output is inputted to control circuits 11 and 12 via an inverter device, respectively, and monitors the fault of the power disconnection of another system. Assuming that the control circuit 11 is operated as the normal system and the control circuit 12 as the spare system, when the fault of the power disconnection is generated in the normal system, the signal of the another system monitoring line 5 outputs the signal to the control circuit 12 and the negative logic input terminal of an OR device 14, and the control circuit 12 informs the fact to the host device. Meanwhile, the OR device 14 outputs the signal to the control circuit 12, and its own system is switched from the spare system to the normal system autonomously, and simultaneously, a command to input the output of the control circuit 12 is issued to the digital line termination controller. In such a way, it is possible to shorten the signal stop time.

Description

[Detailed description of the invention] Industrial applications TECHNICAL FIELD This invention relates to digital electronic exchanges, and more particularly.

This invention relates to a system switching system for a digital line termination control device that controls digital lines.

2. Description of the Related Art A digital electronic exchange that accommodates digital lines is equipped with a digital line termination device and a digital line termination control device that controls the digital line termination device. Since digital lines generally have a single-layer configuration, the digital line termination device that interfaces with the digital line also has a single-layer configuration.

On the other hand, the digital line termination control equipment has a redundant configuration and is duplexed to ensure high reliability.One side controls the digital line termination equipment as a regular system, and the other is on standby as a standby system, so that when the regular system fails, The protection system and abuse system are switched, and the conventional protection system is switched to the regular system to control the digital line termination equipment. Furthermore, the digital network, which is a host device that controls the digital line termination control device, also has a duplex configuration. Control signals and communication signals between the digital network and the digital line termination control device, and between the digital line termination control device and the digital line termination device are transmitted through the paths shown in Figures 11 and 11.

In other words, control signals and speech signals are transmitted from the digital line termination controller of the regular system to the digital line terminal equipment, and from the digital line terminal equipment, control signals and speech signals are transmitted to the digital line termination controllers of both the regular system and the protection system. is transmitted.

Conventionally, switching between a regular system and a standby system in a digital line termination control device with a duplex configuration has been performed only by a command from a higher-level device.

FIG. 3 shows a switching circuit between an active system and a standby system of a digital line termination control device according to the prior art.

Next, according to FIG. 3, the conventional power supply Ffr!
The system switching operation of the regular system and standby system in the event of a failure will be explained.

In Figure 3, the regular system and standby system are designated by the system designation signal line from the host device! and Ko.

The system designation signal is input to the control circuits /l and l, which determines the regular system and standby system of the digital line termination control device, and which system of digital line termination control IT the digital line termination device should input the signal from. It is outputted to the signal line 3 and the terminal as a system designation signal to be determined, and is inputted to the digital line termination device.

The digital line termination control device has other system monitoring lines YO and 6 which mutually monitor other systems, and their outputs are manually inputted to control circuits //P and /2, respectively, to monitor the power supply@failure of the other system. The signal line YO and 6 are connected from the inverter element to the skin L.
A level signal is being supplied, but if a '1 power-off fault occurs, the output of the inverter element becomes a high-impedance state, and the control circuits // and /co detect this change in other systems, causing the other systems to shut off the power. Sense obstacles.

Signal lines 2 and D are data buses for transmitting control signals p and speech signals from the digital line control device to the host device. Signal lines g and 10 are data buses that transmit control signals and speech signals from the host device to the digital line control device.

When the control circuit // is operating as a regular system and the control circuit / is operating as a standby system, if a failure occurs in which the power supply to the regular system control circuit /l is cut off, the cooking signal line 3 is switched to L.
The level changes from high impedance to high impedance, and due to this change, the standby system control circuit 1 senses a power failure in the main system.

The standby system control circuit/U outputs other system ta failure information to the data bus 9, and notifies the higher-level device of the power-off of the main system. The host device 'it sends a system designation signal &! based on the other system power failure information sent from the control circuit/co. By inverting the signal logics of / and C, and newly outputting a system designation signal that makes the control circuit 12 the regular system and the control circuit // the standby system to the signal lines l and co, the digital line termination control device is implemented. system switching is performed.

Problems to be Solved by the Invention In the system switching system of the conventional digital line termination control device described above, when a power failure occurs in the main system, the failure is detected by the control circuit in the standby system and is notified to the host system as a power failure in another system. After that, system switching between the regular system and standby system of the digital line termination control device is performed in response to a system switching command from the higher-level device, so system switching is actually performed when a source failure occurs in the regular system. Until then, it takes several milliseconds to several seconds for the control circuit to process notifications of power failures in other systems to higher-level devices, analyze the failure information in higher-level devices, and process system switchover commands. . During this time, both systems of the digital line termination control device become standby systems, and the digital line termination device receives control signals 2 and call signals only from the digital line termination control device of the regular system, as shown in Figure 11. , the digital line termination device receives the control signal p from the digital line control device.
It has the disadvantage that it cannot receive call signals and the Isa signal sent to the digital line is temporarily stopped.

The present invention has been made in view of the above-mentioned conventional situation,
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a new system switching system for a digital line termination control device that makes it possible to eliminate the above-mentioned drawbacks inherent in the conventional technology.

Means for Solving the Problems In order to achieve the above object, a system switching system for a digital line and termination control device according to the present invention includes a detection circuit that mutually detects a power-off failure in other systems, and a superordinate A circuit that determines the own system as the regular system based on the logical sum of the regular system command from the device and the other system power failure alarm output from the other system power failure detection circuit is installed in the digital line termination control device of both systems. It is composed of

Embodiment Next, the present invention will be described with reference to a preferred embodiment thereof:
This will be explained in detail with reference to the following.

FIG. 1 is a block diagram showing an embodiment of a regular system/protection system switching circuit of a digital line termination control device according to the present invention. Referring to the gz diagram, designation of the regular system and the standby system is normally performed by system designation signal lines l and ko from the host system rIL (not shown). System designation signal QR element /3h and /
The signal is input manually to the control circuit// and l via the controller, and the digital line termination controller determines the skin system and standby system of the digital line termination controller, and the digital line termination inputs the signal from which system of the digital line termination controller. It is output to system designation signal lines J, D, and Hiro as a system designation signal that determines whether it should be executed.

The signal is input to a digital line termination device (not shown). The digital line termination control device has other system monitors m j D and 6 that mutually monitor other systems, and their outputs are manually operated via the control circuits //h and /-inverter elements, respectively. The OR element/
It is input to 32 and llI, and functions to switch the own system to the active system in the event of a power-off failure in another system.

Signal lines 7 and D are data buses for transmitting control signals P and speech signals from the digital line termination control device to the host device.

Signals I@t and 10 are data buses that transmit control signals 2 and speech signals from the host device to the digital line termination control device.

Here, the control circuit vPl/ now operates as a regular system.

It is assumed that the control circuit/co is operating as a standby system.

A 1L level "signal" is sent to the system designation signal line l from the host device, and a 1H level A/" signal is sent to the system designation signal line - from the host device. Each system designation signal passes through an inverter element, and an "H level" signal is input to the positive logic input terminal of OR element/3.

A 1L level signal is input to the positive logic input terminal of the OR element Lda.When the power supplied to both system digital line control devices is normal, the other system monitoring line 5 and AK output a 1L level signal. and are input to the negative logic input terminals of OR elements /3 and /4 (via inverter elements, respectively).
As a result, the OR element 13 outputs a 1H level'' (common system) signal to the control circuit // as a system designation signal.

OR element /4' outputs a 1L level'' (protection system) signal to control circuit l as a system designation signal.

If a power-off failure occurs in the regular system digital line termination control device, the other system monitoring line! The signal logic changes from an "L level" signal to a high impedance state, and the inverter element connected to signal line j is connected to control circuit lko2 and OR element /q.
An "L level" signal is output to the negative logic input terminal of the terminal. When the control circuit 12 detects a power failure in the regular system, it outputs other system power failure information to the data bus t, and notifies the host device of the power failure in the regular system. On the other hand, the OR element /lI outputs an "H level" (regular system) signal to the control circuit l, autonomously switching its own system from the standby system to the regular system, and at the same time sends a "1L level" signal to the system designation signal line t. output, and instructs the digital line termination device to input the output of the control circuit l.

After that, the host device instructs the digital line termination control device to switch between the regular system and the standby system.

The @H level # signal is output to the system designation line l, and the @L level signal is output to the system designation line.At this time, the positive logic input terminal of the OR element/44 becomes the "H level", but the The output continues to be 1H level'' (regular use) signal to the control circuit/
While outputting to J, the control circuit /λ continues to operate as a regular system.

As described in detail, according to the present invention, both systems of the digital line termination control device are provided with a mutual system power-off failure detection circuit;
By installing a circuit that determines the own system as the regular system based on the logical sum of the regular system command from the host device and the other system power failure alarm output from the other system power failure detection circuit, one of the regular systems In the event of a power failure, the backup system autonomously switches to the working system without relying on system switching commands from higher-level equipment, reducing the time required for system switching and stopping signals sent to the digital line. This has the effect of shortening the time required to do so.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram showing an embodiment of a switching circuit for a regular system and a standby system of a digital line termination control device according to the present invention, and FIG. Figure 3 is a block diagram showing the transmission route (F) of control signals and voice signals from the digital line terminal device to the top rank 1g, FIG. 2 is a block diagram of a switching circuit between a regular system and a standby system of a digital line termination control device according to the prior art. 1. Co... System designated signal line (from the host device to the digital line termination control device), j, 41... System designated signal line (from the digital line termination control device to the digital line termination device), t, 4 ... Other system monitoring line, 7. t. 9.10...Data bus, //, /2...Control circuit, /3. /Hiroshi...Order (OR) element patent applicant Representative of NEC Co., Ltd. Patent attorney Yutabe Kumagai Figure 1 Figure 3

Claims (1)

[Claims] In a digital line termination control device that performs redundant operation with one side as a regular system and the other as a standby system due to a duplex configuration, controls the digital line termination equipment from the regular system, and performs system switching between the regular system and the standby system based on commands from a host device. , a circuit that mutually detects a power outage fault in other systems, a normal system command from the host device, and the other system power outage fault alarm output from the other system power outage fault detection circuit. By equipping both systems with a circuit that determines the current status, in the event of a power outage failure in the regular system, the standby system can autonomously switch to the regular system without receiving system switching commands from the host system, and continue to operate the digital line termination equipment. A system switching system for a digital line termination control device, which is characterized by controlling.