JPH04323940A - Blown fuse backup system in subscriber exchange system - Google Patents

Abstract

PURPOSE:To offer the backup system when a fuse is blown to reduce the service-down time by restoring the system automatically without need for a maintenance personnel to visit to a required location of the system and for replacement of a fuse when the power supply fuse to a subscriber circuit is blown due to a transitory cause in the subscriber exchange system. CONSTITUTION:The subscriber exchange system provided with plural subscriber circuits 1-4 operated under the control by a system controller 15, a power supply protection fuse 9 provided corresponding to plural subscriber circuits, a feeder 11 and a means 14 informing interrupt information to the system controller when the power supply protection fuse 9 is blown out is provided newly with a standby system fuse 10 not used when the power supply protection fuse 9 is normal so that the standby system fuse 10 is selected automatically based on the interrupt information 14 when the power supply protection fuse 9 is blown out thereby continuing the service to the subscriber.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup method for preventing a system failure in a subscriber switching system including subscriber circuits when a power supply fuse to the subscriber circuits is blown.

0002

2. Description of the Related Art In a conventional subscriber switching system, as shown in the configuration shown in FIG. 2 and the fuse blown recovery flow shown in FIG. The power supply line 11 and the fuse 9 installed on the power supply line are not duplicated, and when the fuse is blown, the blown information 14 is reported to the maintenance person as a fuse blown alarm, and the maintenance person replaces the fuse ( 305), it was supposed to recover from service interruption due to a blown fuse.

[0003] Regarding this type of device, for example, NTT Research Practical Application Report Vol. 31, No. 11
No. (1982) (pp. 2053-2063), in “Overlay Installation of Digital Subscriber Line Exchange”, p. 2055 “
There are some methods described in Section 2.2 "Internal power supply format", but these do not have duplex fuses.

0004

[Problem to be Solved by the Invention] In the above-mentioned conventional technology, even if the cause of the fuse blowing is a temporary factor such as simultaneous calling by subscribers accommodated in the power supply line, the fuse blows once. Once the fuse has blown, the only way to restore it is for the maintenance person to replace the fuse, so until the maintenance person goes to the system location and replaces the fuse, the subscribers accommodated in the power supply line with the blown fuse will not be able to recover. The problem was that all services were out of service and it took a long time to recover.

[0005] An object of the present invention is to automatically recover when a fuse is blown due to a temporary factor without the need for a maintenance person to go to the location of the system and replace the fuse, thereby shortening the service recovery time. The purpose of this invention is to provide a backup method when a fuse is blown.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention newly provides a standby fuse that is not used when a normal power supply protection fuse is not blown, or
A power supply line that includes this is installed, so that when a normal power supply protection fuse is blown, the service is automatically switched to a backup system fuse based on the blown information, so that service can continue.

[0007] Furthermore, in order to ensure service to important subscribers at the minimum after switching to the standby fuse, and to prevent the standby fuse from being blown due to temporary factors such as making simultaneous calls again, Restricting the service target subscribers to only important subscribers, or setting up a certain number of service allowances n in addition to important subscribers, (number of important subscribers + n)
This system limits the number of subscribers eligible for the service.

Furthermore, in addition to the above, the upper limit of the power supply current for telephone calls from the subscriber circuit to the terminal is limited to a certain current value or less.

[0009]

[Operation] If the normal power supply protection fuse is blown,
Based on the disconnection information, the backup system fuse or
It operates to switch to the power supply line that includes it. As a result, power will be supplied to subscriber circuits housed in the system where the fuse has blown, even if maintenance personnel do not have to replace the blown fuse. Even if a power outage occurs, the service will not be interrupted for a long time and the service can be continuously provided.

[0010] Furthermore, when the backup system fuse is switched, based on that information, the number of subscribers to be served is limited to only important subscribers or important subscribers + non-important subscribers n, so that calls can be made all at once, etc. Since the increase in power supply current flowing through the standby fuse due to temporary factors can be suppressed, the standby fuse is prevented from blowing, and service to important subscribers can be secured with priority.

[0011] Furthermore, based on switching information of the standby fuse, the power supply current flowing through the standby fuse is reduced by limiting the power supply current for telephone calls to the terminal of the subscriber circuit that is supplied with power by the switched fuse. Therefore, it is possible to prevent the backup system fuse from blowing.

0012

[Embodiment] A first embodiment of the present invention will be described below with reference to FIGS. 1 and 4.
This is explained by: FIG. 1 shows the configuration of this embodiment, and FIG. 4 shows the service interruption recovery flow when a fuse blows in this configuration. First, the configuration will be explained. In Figure 1,
1 to 4 are subscriber circuits in the exchange; 5 to 8 are subscriber lines and subscriber terminals accommodated in these subscriber circuits; 11
is the operating current I of the subscriber circuit for subscriber circuits 1 to 4.
Si (i=1 to n) and the supply current ILi to the subscriber terminal
(i = 1 to n) (this embodiment shows an example in which the subscriber circuit operates with one power supply VBB), 2
0 is a line concentrator consisting of a subscriber circuit, a power supply line, and other line concentrator circuits (not shown in FIG. 1); 12
9 is a common power supply device for supplying power VBB to subscriber circuits and other devices; 9 and 10 are fuses to protect the common power supply device from overcurrent on the power supply line 11 side; 10 is a backup fuse that is used when fuse 9 is blown; 13 is a changeover switch for switching to backup fuse 10 when fuse 9 is blown; 14 is a switch that is used when fuse 9 is blown; 15 is a system controller that controls the entire system including call processing and maintenance information, 16 is SLIC control information for controlling the state of subscriber circuits, and 17 is a call path setting. 18 is a highway for transmitting and receiving communication data between the line concentrator 20 and the network 17; 19 is the network 1;
This is network control information for controlling 7. Next, referring to FIG. 4, a method of recovering from a service interruption when a fuse blowout occurs in this embodiment will be described.

In FIG. 1, normal side FUS due to temporary factors such as simultaneous calls by many subscribers in normal service state.
When E0 disconnection occurs (402), FUSE0
The USE disconnection information 14 is sent to the system controller 15 and FU.
The information is sent to the SE changeover switch 13 (403), and the FUSE changeover switch 13 is closed based on the information, and the FUSE changeover switch 13 is closed.
1 is automatically connected, and FUSE0 is replaced with disconnected FUSE0.
The common power supply 12 is operated to be supplied to the subscriber circuits 1 to 4 via USE1 (404). At the same time, the system controller 15 receives FUSE disconnection information and displays it as alarm information on maintenance equipment, etc. (404■)
After confirming this, the maintenance person replaces FUSE0 (405), restores the selector switch 13, and switches the FUSE0
Steps are taken to restore the state to the state before the power failure (406).

According to this embodiment, the service to the subscriber is only momentarily interrupted from when FUSE0 is disconnected until it is switched to FUSE1, and compared to the conventional system in which the service is restored by maintenance personnel replacing the fuse, the service is interrupted. This has the effect that the time required for this can be extremely shortened.

Next, a second embodiment of the present invention will be explained with reference to FIGS. 1 and 5. In this embodiment, in the configuration shown in FIG. 1 explained in the first embodiment, for example, subscriber 1 and subscriber 2 are important subscribers such as police and fire department, and other subscribers 3 to n are non-important subscribers. Assuming the configuration as a subscriber.

A method of recovering from a service interruption when a FUSE0 interruption occurs in this embodiment will be explained with reference to FIG. FUS
When E0 disconnection occurs (502), FUSE0
SE disconnection information 14 is sent to the system controller 15 and FUS.
The information is sent to the E selector switch 13 (503), and the system controller displays the information as alarm information to maintenance equipment, etc. (504■), and also sends the information to the SLIC
According to the control information 16, SLIC1 and SLIC2 that accommodate subscriber 1 and subscriber 2, which are important subscribers, are in the same state as during normal service, and subscribers 3 to 2, which are non-important subscribers, are kept in the same state as during normal service.
For SLIC3 to SLICn that accommodate subscriber n, the call current power supply function to the terminal is stopped, and even if subscriber 3 to subscriber n off-hook terminals 7 to 8 to make a call, IL3 to ILn will not flow. It operates to set the status (504■). Further, the FUSE selector switch 13 is closed by the FUSE disconnection information 14, FUSE1 is automatically connected, and FUSE1 is automatically connected in place of the disconnected FUSE0.
The common power supply 12 is operated to be supplied to the subscriber circuits 1 to 4 via E1 (504). The subsequent procedures and operations are the same as those in the first embodiment, and will therefore be omitted.

According to this embodiment, FUSE0 is disconnected and FUSE0 is disconnected.
While switching to USE1 and providing services,
Since we limit the service target subscribers to only important subscribers and turn off the power supply to non-important subscribers, while the service is being switched to FUSE1, a simultaneous call occurs again and the backup system FUSE1 is switched off. This has the effect of further improving the reliability of the system by preventing disconnections.

Next, a third embodiment of the present invention will be explained with reference to FIGS. 1 and 6. This embodiment has the same configuration as the second embodiment, but differs in operation. Therefore, a description of the configuration will be omitted, and only the differences in operation will be described. In this embodiment, the system controller 15 uses the FUSE 0 disconnection information 14 to control the service target subscribers to 1 important subscribers (in the configuration of this embodiment, 2 subscribers 1 and 2) using the SLIC control information 16. ), and the number of unimportant subscribers allowed to receive service without being interrupted by FUSE1 even if a simultaneous call occurs is k people (the total number of serviceable subscribers allowed without being interrupted by FUSE1 is m people). Then, m = l + k.), important subscribers are always available for service, and non-important subscribers are placed in the order of service requests due to off-hook or incoming calls until the k number of seats are filled. Non-important subscribers are kept in a state where power can be supplied to their terminals, but when the k number of seats are filled, the remaining non-important subscribers who have not received any other service requests are operated to stop the call current power supply function ( 604■).

According to this embodiment, the number of subscribers to be served is limited to a certain number within the range that FUSE 1 cannot cut off, so in addition to the effects of the second embodiment, the number of subscribers to be served can be increased. effective.

Next, a fourth embodiment of the present invention will be explained with reference to FIGS. 1, 7, and 8. In the third embodiment,
By limiting the number of serviceable subscribers or serviceable subscribers, disconnection of the backup system FUSE1 is prevented, but in this embodiment, the amount of communication current to the terminal of the off-hook subscriber is limited. This is to prevent FUSE1 from being disconnected. The configuration is the same as the configuration in FIG. 1 described in the first embodiment. However, SLIC1 to SLICn
The communication current supply characteristics to the terminal have the characteristics shown in FIG. In this embodiment, when FUSE0 is disconnected, the FUSE disconnection information 14 from FUSE0
When the USE changeover switch 13 operates and FUSE1 is connected, the communication current supply characteristics of SLIC1 to SLICn change from a to b in FIG. For subscribers with small subscriber loop resistance, that is, subscribers near the office, the communication current decreases (in the example of subscriber loop resistance R1 in FIG. 8, I1 to I0
decreases to ), and therefore operates to reduce the current flowing through the FUSE 1 installed on the power supply line 11 that supplies it (704■). The other operations are the same as those in the other embodiments, so their explanation will be omitted.

According to this embodiment, the current flowing through FUSE1 is reduced by limiting the call current supplied to the terminal, so FUSE1 can be disconnected without limiting the number of serviceable subscribers or serviceable subscribers. can be prevented.

[0022] In the description of each of the above embodiments, F
Although the USE changeover switch has been described as being switched in response to FUSE0 disconnection information, a configuration in which it is switched in response to FUSE changeover information from the system controller 15 which has received FUSE0 disconnection information is also conceivable. The effect is the same.

[0023]

[Effects of the Invention] According to the present invention, when a fuse for power protection is blown, it is automatically switched to a backup fuse without the need for a maintenance person to replace the fuse. Power supply continues through the system fuse,
This has the effect of providing a backup system in the event of a fuse blowout, which can reduce service down time to an extremely short period of time during fuse switching.

Furthermore, according to the present invention, when service is performed by switching to the standby fuse, the subscribers to be served are limited to only important subscribers, so that if the cause of fuse blowing occurs again, such as when a simultaneous call is made, This has the effect that the backup system fuse does not blow, and it is possible to provide a more reliable backup method for important subscribers only in case of a fuse blowing.

Further, according to the present invention, when the backup system fuse is switched to provide service, the number of subscribers to be served is limited to the number that can be tolerated without blowing the backup system fuse, and important subscribers are always The service will be applied to non-important subscribers in the order of earliest service requests within the remaining number of subscribers, and the other subscribers will have their call current supply function stopped and will not be eligible for the service. This has the effect of providing a fuse blowing backup method that can increase the number of users.

Furthermore, according to the present invention, the current flowing through the protection system fuse is reduced by limiting the call supply current of the subscriber circuit when switching the protection system fuse, thereby limiting the number of serviceable subscribers or serviceable subscribers. This has the effect of providing a highly reliable backup method in the event of a fuse blowout without having to do so.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional configuration.

FIG. 3 is a service interruption recovery flow when a fuse is blown in a conventional configuration.

FIG. 4 is a service interruption recovery flow when a fuse is blown in the first embodiment of the present invention.

FIG. 5 is a service interruption recovery flow when a fuse is blown in a second embodiment of the present invention.

FIG. 6 is a service interruption recovery flow when a fuse is blown in a third embodiment of the present invention.

FIG. 7 is a service interruption recovery flow when a fuse is blown in a fourth embodiment of the present invention.

[Fig. 8] Fig. 8 shows the normal time (FUSE0
FIG. 4 is a diagram showing the characteristics of the supply current ILi during a call when switching the backup system fuse (when using FUSE1) and when switching the standby system fuse (when using FUSE1).

[Explanation of symbols]

1 to 4...Subscriber circuit 15...System controller 9…Power protection fuse 10...Spare fuse 11...Power line 14...FUSE disconnection information 13...Fuse selection switch 16...SLIC control information

Claims (4)

[Claims] Claim 1: Under control from a system controller,
A plurality of subscriber circuits that provide services to subscribers, a power supply protection fuse provided corresponding to the plurality of subscriber circuits, a power supply line that supplies power to the plurality of subscriber circuits via the fuse, and a power supply line that supplies power to the plurality of subscriber circuits via it; In a subscriber exchange system that has means for transmitting disconnection information to the system controller when a power protection fuse is blown, a standby fuse that is not used when the power protection fuse is normal, or a supply that includes it is added. A fuse blown backup system for a subscriber exchange system, characterized in that when an electric wire is installed and the power supply protection fuse is blown, the fuse is automatically switched to a standby fuse based on the blown information to continue the service. [Claim 2] Based on the disconnection information when the power supply protection fuse is disconnected, the system controller limits the subscribers to be served to only important subscribers among the subscribers accommodated in the power supply line where the fuse has disconnected. A fuse blowing backup system for a subscriber switching system according to claim 1, characterized in that: [Claim 3] Based on the disconnection information when the power supply protection fuse is disconnected, the system controller, among the subscribers accommodated in the power supply line where the fuse has disconnected, always treats important subscribers as service target subscribers, and For those who wish to receive service, a certain number of service targets will be set up, and service requests will be accepted from all non-essential subscribers until the specified number of service areas is full. 2. The fuse blowing backup method for a subscriber switching system according to claim 1, wherein non-important subscribers are excluded from service. 4. After switching the backup system fuse, the power supply current for telephone calls from the subscriber circuit accommodated in the power supply line to the terminal is limited to a certain current value or less based on the switching information. A fuse blowing backup system for a subscriber switching system according to claim 1, claim 2, or claim 3.