JP2689955B2 - Line switching device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line switching device, and more particularly to a wireless communication line switching device.

[0002]

2. Description of the Related Art Conventionally, a line switching device for switching a working transmission line and a backup transmission line by an atypical switching system is disclosed in, for example, Japanese Patent Laid-Open No. 4-291521.
FIG. 6 shows the configuration. The conventional line switching device 1 includes a line switching unit 3 that switches between the working transmission line 2a and the backup transmission line 2b, and an atypical position switching control unit 4 that controls switching of the line switching unit 3. Line switching unit 3
The transmission line output 7 that has passed through is input to the line monitoring control device 5 through the transmission line 8 and the line monitoring information is extracted. A control signal is input from the line supervisory control device 5 to the non-localization switching control unit 4 via the active system control line 9a and the standby system control line 9b. Working transmission line 2a
The backup transmission line 2b and the backup transmission line 2b are respectively connected to the alarm detector 1
The presence or absence of an alarm is detected by 0a and 10b, and when there is an alarm, the alarm signals 11a and 11b are input to the non-stereoscopic switching control unit 4.

In such a system, when switching from the working transmission line 2a to the protection transmission line 2b by remote control, for example, a remote switching signal from a geographically distant monitoring station (not shown) is used as the working transmission line 2a.
Alternatively, it is transmitted through the backup transmission line 2b. When this remote switching signal is detected from the transmission line output 7 by the line monitoring control device 5, the line monitoring control device 5 outputs a remote control signal to the non-localization switching control unit 4 through the control lines 9a and 9b, and the non-localization is performed. The switching control unit 4 outputs the line switching signal 13 to the line switching unit 3, and the line switching unit 3 causes the working transmission line 2 a to the backup transmission line 2 to be switched.
Switched to b. Further, when an alarm is detected by the alarm detection unit 10a or 10b, the atypical position switching control unit 4 outputs the line switching signal 13 to automatically switch the line switching unit 3. Here, the switching logic adopts a non-localization control logic so that unnecessary switching (failback due to alarm recovery) does not occur. In addition, the non-localization switching control unit 4 adopts a switching control method that prioritizes automatic control over remote control to prevent erroneous operation. That is, remote control is enabled only when both the working transmission line 2a and the standby transmission line 2b are normal, and a transmission line in which signal transmission is disabled due to an alarm is selected, This prevents the problem that the remote switching signal for switching back to the original normal line cannot be transmitted.

[0004]

However, in this conventional line switching device, since automatic control is prioritized over remote control, the transmission line in which the alarm has occurred is intentionally selected and the alarm in which it occurs. It was not possible to ascertain whether or not the signal transmission is actually a hindrance, or whether the signal transmission is actually possible due to an abnormality in the alarm detection system.

An object of the present invention is to enable remote selection of the transmission line side in which an alarm is occurring, and whether the transmission line on the alarm side is in a state in which signal transmission is impossible,
An object of the present invention is to provide a line switching device that can confirm whether or not a signal can be actually transmitted.

[0006]

A line switching device according to the present invention has a basic configuration that has been used in the past, that is, a line switching unit for switching between a working transmission line and a backup transmission line, and a remote control from a line monitoring control device. The line switching unit is switched by remote control by a signal, and the line switching unit is automatically controlled by an alarm signal related to the alarm detection of the working transmission line and the standby transmission line. Equipped with a remote control detector that converts a control signal into a control pulse signal of a fixed time width and inputs it to the atypical position switching control unit.The atypical position switching control unit prioritizes remote control switching over automatic control switching. It uses a control method. That is, the non-localization switching control unit has a priority of remote control that prioritizes switching by remote control over switching by automatic control, and once the control pulse signal is input from the remote control detection unit, the standby transmission line is temporarily selected. Output a line switching signal to the line switching unit, forcibly switching from the working transmission line to the backup transmission line, and after a certain period of time, if the backup transmission line is normal, leave the backup transmission line selected, When the standby transmission line is in an alarming state, the line switching unit is controlled to automatically switch back to the working transmission line.

The line switching device according to the present invention further determines the presence / absence of the forced fixation signal from the line supervisory control device, and outputs the output of the remote control detection unit when the forced fixation signal is present.
A forced switching determination unit for returning the control pulse signal to the original remote control signal can be provided.

[0008]

When performing remote switching from the working transmission line to the protection transmission line, the remote switching signal from the monitoring station is transmitted through the working transmission line or the protection transmission line and detected by the line supervisory controller from the transmission line output. Then, a remote control signal of, for example, NRZ (Non-Return-to-Zero) format is output from this line supervisory control device to the non-localization switching control unit, and this remote control signal is controlled by the remote control detection unit with a constant time width. It is converted into a pulse and input to the ataxic switching control unit. Since the non-localization switching control unit has priority over remote control, the non-localization switching control unit always outputs a line switching signal that always selects the backup transmission line, forcing the transmission line to the backup transmission line. Can be switched. Then, after a certain period of time, if the backup transmission line is normal, the backup transmission line remains selected because of the non-stereo switching method,
When the backup transmission line is in an alarm state, it is switched back to the working transmission line by the automatic switching function.

If it is found that the transmission line for which an alarm has been generated is in a state in which signals can be transmitted and it is desired to forcibly fix the transmission line by remote control,
A forced fixation signal is output from the line supervisory control device, and the output of the remote control detection unit is returned from the control pulse signal to the original NRZ format signal, whereby the forced fixation by remote control is realized.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a first embodiment of the present invention. The line switching device 1A includes a line switching unit 3 for switching between the working transmission line 2a and the backup transmission line 2b as in the conventional case,
In addition to having a non-localization switching control unit 4 that controls switching of the line switching unit 3, a remote control detection unit 6 is further provided between the line monitoring controller 5 and the non-localization switching control unit 4.

Transmission line output 7 passing through the line switching unit 3
Is input to the line monitoring controller 5 through the transmission line 8 as in the conventional case. When there is a remote switching signal in the transmission line output 7, the line supervisory control device 5 converts this into a NRZ format remote control signal for each of the working system and the standby system, as shown in FIG. It is output to the remote control detection unit 6 through the active system control line 9a and the standby system control line 9b. The active transmission line 2a and the standby transmission line 2b are respectively provided with an alarm detector 10
The presence / absence of an alarm is detected by a. 10b, and if there is an alarm, the alarm signals 11a, 11b are input to the non-stereoscopic switching control unit 4.

The remote control detector 6 converts the input remote control signals of the NRZ format of the working system and the standby system into control pulse signals of a constant time width τ as shown in FIG. It is output to the non-stereoscopic switching control unit 4 through the lines 12a and 12b. Contrary to the conventional method, the atypical position switching control unit 4 adopts a switching control system that prioritizes remote control over automatic control.

In such a system, when remote switching is now performed from the working transmission line 2a to the protection transmission line 2b, a remote switching signal from a monitoring station (not shown) is transmitted to the working transmission line 2a or the protection transmission line. 2b
And is detected by the line switching control device 5. The line switching control device 5 converts this remote switching signal into a remote control signal in the NRZ format as shown in FIG. 2 and outputs it to the remote control detection unit 6 through the control line 9b. The remote control detection unit 6 converts this remote control signal into a control pulse signal having a constant time width τ as shown in FIG. 2, and the atypical position switching control unit 4 through the control line 12b.
Output to Here, since the non-positional switching control unit 4 is given priority to the remote control, when the control pulse signal is input from the control line 12b, the line switching that always selects the standby transmission line 2b as shown in FIG. Signal 13
To the line switching unit 3.

The line switching section 3 to which the line switching signal 13 has been input is changed from the working transmission line 2a to the backup transmission line 2
Switch to b. When the standby transmission line 2b is normal after the elapse of a certain time τ, the standby transmission line 2b remains selected because the non-localization switching method is used, and when the standby transmission line 2b is in the alarm generation state, The automatic switching function automatically switches back to the working transmission line 2a.
Therefore, even if an alarm occurs in the backup transmission line 2b, it is possible to switch to the backup transmission line 2b once, and even if the backup transmission line 2b is in a state in which signal transmission is impossible, the normal side is reached after a certain time τ. Since it is switched back to (the working transmission line 2a in this case), transmission of various control signals including the remote switching signal and the supervisory signal is not disabled.

Next, FIG. 3 shows a second embodiment of the present invention.
This line switching device 1B has the configuration shown in FIG. 1 with a forced switching determination unit 14 added. Forced switching determination unit 14
The control signal from the line monitoring controller 5 is obtained by branching the control lines 9a and 9b from the line monitoring controller 5 to the remote control detecting unit 6 as shown in FIG. 4A or 4B. Is branched and input. Then, when the control signal from the line supervisory controller 5 is a forced fixed signal including a pulse component, the forced switching determination unit 14 controls the control signal conversion unit 15 in the remote control detection unit 6 to perform remote control. The output from the detector 6 is changed to a remote control signal in the NRZ format.

The operation of the second embodiment will be described. As described in the first embodiment above, after switching from the active transmission line 2a to the backup transmission line 2b by remote control, it is found that the transmission line in which an alarm has occurred is in a signal transmittable state, and the transmission When the line is to be forcibly fixed by remote control, the monitoring station transmits a forcibly fixed signal containing a pulse component by intermittently connecting the line several times in a fixed time through the working transmission line 2a or the backup transmission line 2b.

FIG. 5 shows a case where a forced fixation signal for forcibly fixing the backup transmission line 2b is detected by the line supervisory control device 5, and the detected forced fixation signal is controlled by the line supervisory control device 5. It is input to the remote control detection unit 6 and the forced switching determination unit 14 through the line 9b. As shown in FIG. 5, the forced switching determination unit 14 outputs the NRZ format signal to the control signal conversion unit 15 of the remote control detection unit 6 after a predetermined number of pulses of the forced fixed signal are input,
The control signal converter 15 which receives this converts the control pulse signal having the constant time width τ shown in FIG. 2 into the original remote control signal in the NRZ format, and restores the original remote control signal to the control line 12a. The backup transmission line 2b is forcibly fixed by outputting from 12b to the non-stereoscopic switching control unit 4.

[0018]

As described above, according to the present invention, an alarm is generated even when switching from the working transmission line to the protection transmission line by remote control or conversely from the protection transmission line to the working transmission line. However, since it is possible to remotely select the alarm side, it may be because the transmission line in which the alarm is occurring is in a state in which signal transmission is not possible, or due to false alarm detection, etc. It is possible to confirm whether or not it is possible. According to the second aspect, after performing the above confirmation, the normal transmission line can be forcibly fixed by remote control.

[Brief description of the drawings]

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

FIG. 2 is a timing chart of a switching operation according to the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of the present invention.

FIG. 4 is a block diagram showing a relationship between a remote control detection unit and a forced switching determination unit in FIG. 3 for two examples (A) and (B).

FIG. 5 is a timing chart of a forced fixing operation according to the second embodiment.

FIG. 6 is a block diagram of a conventional example.

[Explanation of symbols]

 1A / 1B line switching device 2a working transmission line 2b backup transmission line 3 line switching unit 4 non-stereo switching control unit 5 line monitoring control unit 6 remote control detection unit 7 transmission line output 8 transmission line 9a / 9b control line 10a / 10b alarm Detection unit 11a / 11b Alarm signal 12a / 12b Control line 13 Line switching signal 14 Forced switching determination unit 15 Control signal conversion unit

Claims (2)

(57) [Claims] 1. A line switching unit for switching between an active transmission line and a backup transmission line, and a remote control signal from a line supervisory control device for switching the line switching unit by remote control to alarm the active transmission line and the backup transmission line. In a line switching device having a non-stereoscopic switching control unit that switches the line switching unit by automatic control according to an alarm signal related to detection, the remote control signal from the line monitoring control device is converted into a control pulse signal of a constant time width. A remote control detection unit for inputting to the non-localization switching control unit, and the non-localization switching control unit has a remote control priority that prioritizes switching by remote control over switching by automatic control. By inputting, a line switching signal for selecting the backup transmission line is temporarily sent. Output to the line switching unit, forcibly switching from the working transmission line to the backup transmission line, and after a certain period of time, if the backup transmission line is normal, the backup transmission line remains selected and backup transmission is performed. When the line is in an alarm state, the line switching unit is controlled so as to automatically switch back to the working transmission line. 2. A forced switching judgment for judging whether or not there is a forced fixation signal from the line supervisory control device and for returning the output of the remote control detection unit from the control pulse signal to the original remote control signal when the forced fixation signal is present. The line switching device according to claim 1, further comprising a section.