JPH0497627A - Line changeover device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Summary] Switching to the maintenance line when a service (operation) line fails,
Regarding a line switching device that prohibits switching when a non-service line has a fault, the DC level of each switching control signal is pulled-amplified using a pull-up resistor and received from the line interface section connected to both ends of each of multiple lines, and the DC level is received by a monitoring means. The status of each line is monitored, and if a fault occurs in any one of the lines in service, the faulty line is switched to a maintenance line, and maintenance is carried out on non-service lines or lines that do not have a line interface section. In a line switching device that prohibits switching to a line, maintenance personnel can quickly and automatically switch to a maintenance line without installing a specific switch for a line that is out of service or a line that is not equipped with a line interface. A pull-down resistor that pulls down each switching control signal from the line interface section for the purpose of prohibiting switching to The partial voltage is configured to provide an output level at which the monitoring means prohibits line switching to the maintenance line.

[Industrial application field]

The present invention relates to a line switching device, and particularly to a service (operation)
The present invention relates to a line switching device that switches to a maintenance line when a line fails and prohibits switching when a non-service line fails.

In order to improve the reliability and ensure the quality of operational line networks in PCM multiplex communications, etc., emphasis is placed on increasing the functionality and efficiency of operation and maintenance, and line failures such as disconnections occur in the current lines due to accidents, disasters, etc. In such a case, the line will be automatically switched to the maintenance (backup) line instantly, but the same switching process will be performed pointlessly if a failure occurs on the line that is not in service. Therefore, it is necessary to forcibly prohibit switching to the maintenance line.

[Conventional technology]

Conventional line switching equipment automatically switches to the maintenance line when a service line failure occurs, and prohibits the line from being forcibly switched to the maintenance line by manual operation in the event of a failure on a line that is not in service. ing.

3 and 4 show such a conventional line switching device 1.
0 and a configuration example of a PCM multiplex communication device, L1 to L4 are multiplexed communication lines, and LIUI to LIU4 are connected to both ends of the lines L1 to L4 to monitor the line status. LP is a backup communication line for maintenance, and LIUP is a line interface unit connected to both ends of the maintenance line LP, DLI-DL4 and DL.
P is each line interface section LIUI to LIU4 and L
Separate signal output lines output from the IUP are shown.

In addition, in the line switching device 10, 1 represents each line L1 to
CPU that monitors the status of L4, S2 is a changeover switch that switches lines according to instructions from CPUI, and Sll-314 is C
A disable switch, R1-R4 and R1, generates a disable input that inhibits line switching of PU1.
1 to R14 respectively indicate pull-up resistors connected to the power supply +5V to pull up the switching control signal and the disable input.

In this conventional example, R1-R4 and R11-R14 are both set to 100Ω.

In the operation of such a line switching device 10, first,
As shown in FIG. 3, the CPUI constantly monitors the status of each line L1-L4 by inputting switching control signals from each line interface unit LIUI-LIU4.

For example, when the line L4 is in a service state, if it is in a normal state, the CPU reads the switching control signal with a logical value of "0" sent from the line interface unit LIU4, regardless of the pull-up resistor R4, and the line L4 is in a faulty state. However, if a disconnection fault (indicated by an x mark) occurs, CPU 1
A switching control signal with a logical value of "1" sent from the line L4 is read in a state where it is pulled up by the pull-up resistor R4, and a fault in the line L4 is detected and recognized.

Then, the CPUI instructs the changeover switch S2 to use the maintenance line LP instead of the line L4, and controls the changeover switch S2 to switch to the illustrated position.

As a result, the line interface section LIL14 of the line L4
The separation signal output line DL4 from the selector switch S2
By maintenance AI! It will be replaced by the separation signal output line DLP from the line interface unit LIUP connected to LP, and switching to the maintenance line LP will be performed.

In addition, each line interface section L I U 1 to I-I
The separate signal output lines DLI-DL4 from L14 are actually each connected to a multiplexer (not shown) within the PCM multiplex equipment.

Next, as shown in FIG. 4, the line L4 in the above example is in a non-service state, or the line interface unit LIU
4 is not installed, the line L4 side is considered to be in an oven state and the switching control signal is not sent. Therefore, CPtJl sets +5V to a logical value by the pull-up resistor R4 connected to the power supply +5■. Since it is read as "1", it is detected and recognized as a fault in the line in operation, and as a result, CPU 1 instructs changeover switch S2 to change over to maintenance lines ■ and P. Switching will occur.

However, even after switching to the maintenance line LP,
Since the line L4 is out of service, it is not only wasteful to use it, but also if a failure occurs in another line in service, the maintenance line L4 is used as a backup line for this faulty line. A situation may arise in which the line cannot respond.

Therefore, the maintenance person manually turns on the disable switch 314 and changes the disable input of the CPUI from the logic value "l", which has been set by the pull-up resistor R14, to the logic value "Oj". The switching control signal level corresponding to 1-4 is forcibly regarded as a logical value "0", thereby preventing line failure and, as a result, prohibiting switching to the maintenance line LP.

[Problem to be Solved by the Invention] As described above, in the conventional line switching 1iio, when the line is in a non-service state or a line interface unit is not provided, a maintenance person manually operates the disable switch. This prevents CP IJ 1 from detecting and recognizing a line failure and prohibits switching to the maintenance line.
There is a problem with having to operate a switch.

Therefore, in the present invention, the DC level of each switching control signal is pulled up by a pull amplifier resistor and received from the line interface section connected to both ends of each of the plurality of lines, and the status of each line is monitored by the monitoring means. Line switching that switches the faulty line to a maintenance line when a failure occurs in any one of the lines in service, and prohibits switching to the maintenance line for non-service lines or lines without a line interface unit. The purpose of this system is to quickly and automatically prohibit switching to maintenance lines for lines that are in a non-service state or lines that are not equipped with a line interface part, without the need for maintenance personnel to install a specific switch. shall be.

[Means to solve the problem]

In the line switching device 10 according to the present invention for achieving the above object, as shown in principle in FIG. 1, the line interface unit LIU1. IIU2. LIU3...LI
Pull-down resistors R1', R2', R3'...Rn' pull down each switching control signal from U n, and the pull-up resistor and pull-down resistor are connected except when a failure occurs in the line in service. According to the partial pressure, the monitoring means 1
is provided with an output level that prohibits line switching to the maintenance line LP.

[Function] Each component block shown in principle in FIG.
l, L2. Although only the configuration of the right side portion of L3 to Ln is shown and the configuration of the left side portion is omitted, in reality, the configuration is symmetrical with respect to each line.

As shown in principle in FIG. 1, the monitoring means 1 connects the line interface section LfU1. L[U2 L[l)3...
Pull-down resistors R1'R2', R3'...Rn are pulled down when reading each switching control signal indicating the status of each line LL, L2L3 to Ln sent from LIUn.
If ' is newly provided, n types of series voltage divider circuits made up of pull-amplifier resistors RIR2, R3...Rn and pull-down resistors R1', R2', R3'...Rn' with 'tsv as a reference. will be formed.

Therefore, if the line $1Ln is in a non-service state or the line interface section Ln is not installed (these parts are shown with broken lines in Figure 1), the line Ln will be in an open state and a line switching control signal will be sent. Monitoring means 1
The input is a value obtained by dividing tB■ by the voltage division ratio of pull-up resistor Rn and pull-down resistor Rn', that is, Rn
The DC level of 'V/(R1+Rn') is read as a switching control signal.

At this time, if the monitoring means 1 reads the DC level corresponding to the logical value "0" at the same level as the normal service state by selecting the above-mentioned partial pressure ratio, the monitoring means 1
Regarding n, it is not detected or recognized as a line failure during service, and line switching is not performed.

On the other hand, if line Ln is in the service state and a line failure occurs (these parts are illustrated by solid lines and In this case, the DC level of the switching control signal is superimposed on the DC level value based on the voltage division ratio described above, so the monitoring means 1 reads it as a logical value "1". The line failure of line Ln is recognized and the line is switched to the maintenance line LP.

In this way, by providing pull-up resistors R1, R2, R3, . When not in service or for a line where a line interface unit is not installed, the same level as in normal service status is read, and as a result, the line can be switched to the maintenance line LP without operating a specific switch. will be prohibited.

[Embodiment] FIG. 2 is a diagram showing an embodiment of the line switching device 10 according to the present invention, and also shows an example of the overall configuration of a PCM multiplex communication device, in which R1', R2', R3', R4' indicates a pull-down resistor connected between each of the pull-up resistors R1, R2, R3, and R4 and the ground. Furthermore, in this embodiment, the monitoring means 1 shown in FIG. 100Ω
, the power supply V' is set to +5■, respectively.

Note that the configuration other than these is the same as that of the conventional example shown in FIGS. 3 and 4, and therefore the explanation thereof will be omitted.

The operation of such an embodiment will be described in the case where the line L4 is in a non-service state or the line interface unit LIU4 is not installed, as in the above example.

First, line switching device 1 when the switching control signal is disconnected
The input DC level of CPUI 0 is the value obtained by dividing the power supply +5V by the voltage division ratio of pull-amp resistor R4 and pull-down resistor R4', that is, R4'V/ (R4 + R4')
= approximately 15mV.

At this time, the line L4 is in an open state and no line switching control signal is sent out, so the CPU reads the aforementioned DC level of approximately 15 mV as the switching control signal. When inputting "1" or "0", the value is below the threshold corresponding to the logical value "0", so as a result, the CPU assumes that the logical value "0" has been input, and regarding the line L4. It is not detected or recognized as a line failure during service, that is, it is determined that there is no abnormality in line L4, and line switching is not performed.

That is, there is no need to manually operate the disable switch S14 to forcibly prohibit line switching to the CPU as shown in the conventional example of FIGS. 3 and 4.

In this case, pull-amp resistor R4 and pull-down resistor R4'
Even if the value of is changed from the value given as an example in this example to another value, the value obtained by dividing the voltage of the power supply +5■ (DC level) is
The resistance value is set so as to obtain a voltage division ratio that is sufficiently large within the range of the threshold value that the CPU 1 considers to be the logical value r□.

Further, if a line failure occurs while the line L4 is in service state, the line interface unit LIU4 sends out a switching control signal with a logic value of "1" indicating a line failure, and in this case, the above-mentioned power supply Partial voltage DC level value, approximately 15m
The inflow voltage to the pull-down resistor R4' due to the signal value "1" of the switching control signal is superimposed on V, and the CPU reads it as a level exceeding the dark value of the logic value "L" and connects the line L4.
detects and recognizes line failures in the maintenance line LP.
Switch to

Also, at this time, if the line L4 is in a normal normal state, the line interface unit LIU4 will set the logical value "0" indicating the normal state.
”, and the CPU 1 similarly reads it as a logical value “0”.

The above explanation is exactly the same for the other lines L1 to L3.

In this embodiment, the line &IJIL1 is often always in the service state, and therefore the line L1 and the line interface section LIUI are always in the connected state. Just leave it there.

〔Effect of the invention〕

As explained above, according to the line switching device 10 according to the present invention, each switching control signal from each line interface section is pulled down by the pull-down resistor, and the voltage is divided between the pull-amp resistor and the pull-down resistor except when a service line failure occurs. Since the configuration is configured to prohibit line switching, lines that are in a non-service state or lines that are not equipped with a line interface will not be detected or recognized as a line failure, and maintenance personnel will not be able to switch a specific switch. A line switching device that can quickly and automatically prohibit switching to a maintenance line without any operation will be realized.

[Brief explanation of drawings]

FIG. 1 is a principle block diagram of a line switching device according to the present invention, FIG. 2 is a diagram showing an embodiment of a line switching device according to the present invention, and FIG. 3 is a diagram showing service line switching in a conventional example. FIG. 4 is a diagram showing prohibition of switching of non-service lines in a conventional example. In FIG. 1, IO...Line switching device, 1...Monitoring means, L1-Ln...Line, LIUI-LIUn...Line interface section, LP
...Maintenance line, R1-Rn...Pull amplifier resistor, R1'-Rn'...Pull-down resistor. In the figures, the same reference numerals indicate the same or corresponding parts. Book! ! Figure 1 of the principle of light

Claims (1)

[Claims] A plurality of lines (L1), (L2), (L3), ... (L
line interface unit (LI) connected to both ends of
U1), (LIU2), (LIU3)...(LIUn
) to pull up the DC level of each switching control signal from (
R1), (R2), (R3), . When a fault occurs, the faulty line is switched to a maintenance line (LP), and the maintenance line (LP) is switched to a non-service line or a line where the line interface section is not installed.
In a line switching device that prohibits switching to LP), the line interface units (LIU1), (LIU2),
(LIU3)...Pull-down resistors (R1') and (R2) that pull down each switching control signal from (LIUn)
'), (R3')... (Rn'), except when a fault occurs in the line in service, the monitoring means (1) A line switching device characterized in that the line switching device is provided with a device that provides an output level that prohibits line switching to the maintenance line (LP).