JPH02246549A - Dual switching circuit - Google Patents

Abstract

PURPOSE:To enable a monitor and control board to confirm the connection destination of a line terminating cable automatically by monitoring the switching between 1st and 2nd interface parts where monitor and control boards are arranged successively in parallel by using a signal detected by a carrier detection part. CONSTITUTION:The 1st interface part 12 and 2nd interface part 13 are provided with level converters 1 respectively and the signal from a line terminating device 11 is received and converted into a unipolar signal, which is applied to a carrier detection part 2 to detect and output whether or not the unipolar signal has '1' level. The detection signal of the carrier detection part 2 is sent to the monitor control board 14 through an input/output register 3 to monitor the in-use/stand-by switching between the 1st interface part 12 and 2nd interface part 13 of dual constitution from the monitor control board 14. Consequently, the monitor and control board 14 can confirm the connection destination of the line terminating cable 15.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a supervisory control board that controls data received by a line termination device, and particularly relates to a circuit that switches the redundant interface section from the supervisory control board. The purpose of this system is to enable the supervisory control board to automatically confirm the connection destination of the line termination cable using the synchronization bit included in the received signal of the public communication line, and to transmit data transmitted from the public communication line. A line termination device that outputs a signal received and processed to convert into a bipolar code is connected to one side, and a monitoring control board that controls switching of the received signal from the line termination device is connected to the other side, and the Data from the line termination device is connected to each of a first interface section and a second interface section that are connected in parallel to provide an interface between received signals transmitted and received between the line termination device and the supervisory control board. a level converter that receives and converts it into a unipolar signal of "1' or "0゛ level and outputs it; and when the output of the level converter is 1°, it indicates that the output of "lo" has been detected. A carrier detection unit that outputs a signal and an input/output register that notifies a monitoring control board of the signal detected by the carrier detection unit are provided, and the signal detected by the carrier detection unit and output from the input/output register is used, The monitor control board is configured to monitor switching between the first interface section and the second interface section connected in parallel.

[Industrial application field]

The present invention relates to a supervisory control board that controls data received by a line termination device, and more particularly to a circuit that switches between duplex interface units from the supervisory control board.

[Conventional technology]

FIG. 5 is a diagram showing an example of a conventional circuit configuration.

In the figure, 11 is a line termination device that transmits data including synchronization bits, and 12 is a first interface unit that connects the line termination device 11 with a line termination cable 15.
13 is a second interface section which has the same configuration as the first interface section 12; It is used as a backup side in case of a failure and monitors the received signal. Also 14
is a supervisory control board with a first interface section 12
and one that performs switching control of the second interface section 13,
15 is a line termination cable that connects to the line termination device 11 and transmits received signals; 16 is a redundant cable that connects to the line termination device 11 when the first interface section 12 becomes abnormal; 17 is a data bus that passes the received signal to the second interface section 13; 17 is a data bus that serves as a path for transmission signals; and 18 is a control bus that serves as a path for transmitted control signals. be.

Furthermore, 1.2.4.5 is each unit provided in the first interface section 12 and the second interface section 13, and 1 is the unit that each of the first and second interface sections 12.13 receives. a level converter that converts the level of a received signal including a synchronization bit; 3 an input/output register that connects each of the first interface section 12 and the second interface section 13 with an external device; 4 a relay that drives the relay 5; The driver 5 is a relay, which is connected so that it is in use when contact a is on, and is used as a backup when contact a is on.

In FIG. 5, which shows the circuit configuration of the conventional example, the signal sent from the line termination device 1 is sent to the first interface unit 12 when the first interface unit 12 is currently in use.
It passes through the level converter 1 of the second interface section 13 to reach the data bus 17, and when the second interface section is currently in use, it passes through the level converter 1 of the second interface section 13 and reaches the data bus 17.
Reach 7. The respective signals from the data bus 17 are then received by the terminal device 19.

In the first interface section 12 and the second interface section 13 that perform duplex reception in this way, switching between working and standby is performed in the following procedure.

! , an operator connects the line termination device 11 and the first interface unit 12 using the line termination device 11.

At this time, the first interface section 12 becomes the active side,
The second interface section 13 becomes the standby side. If the line termination device 11 and the second interface section 13 are connected, the second interface section 13 becomes the working side and the first interface section 2 becomes the standby side. The supervisory control board 14 has no knowledge of this information as to whether it is the active side or the backup side, and cannot determine which side is the active side and which is the backup side. That is, at this stage, the two first and second interface sections 1
Since 2 and 13 look the same from the supervisory control board 14, it is impossible to tell which one is currently in use and which one is in reserve.

2. The operator connects the duplex cable 16 between the first interface section 12 and the second interface section 13.

The operator uses the terminal device 19 to control the monitoring and control board 1.
4, information is given to the first interface section 12 and the second interface section 13 as to whether they are on the active side or the standby side. That is, the information that the first interface section 12 is on the active side and the second interface section 13 is on the standby side. Only then can the supervisory control board 14 recognize which side is the active side and which side is the standby side.

3. When the entire device enters the operational state, the monitoring control board 14
drives the relay 5 of the first interface section 12 through the control bus 18 and the relay driver 4 to turn on the contact a. Therefore, the signal from the line termination device 11 is connected to the level converter 1 of the first interface section 12,
The data is sent to the terminal device 19 via the data bus 17. At this time, if an abnormality or failure occurs in the first interface section 12, the supervisory control board 14 turns off the relay driver 4 of the first interface section 12 via the control bus 18. Therefore, the relay 5 of the first interface section 12 falls to the contact point and becomes a standby side, and the signal from the line termination device 11 passes through the duplex cable 16 and is input to the second interface section 13, where it is input to the level converter l. connected to. From this point on, the second interface section 13 replaces the first interface section 12 and becomes the active side for operation. Then, the first interface section 12 is inspected and repaired.

[Problem to be solved by the invention]

Therefore, in the above-mentioned device switching procedure, it becomes necessary for the operator to notify the supervisory control board of the connection information of the line termination cable in advance, resulting in an increase in the operator's workload.

SUMMARY OF THE INVENTION An object of the present invention is to enable the supervisory control board to automatically confirm the connection destination of a line termination cable by using a synchronization bit included in a received signal of a duplexed interface section.

[Means to solve the problem]

In the present invention, a line termination device 11 that receives data transmitted from a public communication line, converts it into a bipolar code, and outputs a signal is connected to one side, and a signal from the line termination device 11 is connected to the other side. A first circuit connected in parallel so as to connect a supervisory control board 14 that controls switching of received signals and to provide an interface between received signals transmitted and received between the line termination device 11 and the supervisory control board 14. Each of the interface section 12 and the second interface section 13 includes a level converter 1 that receives data from the line termination device 11, converts it into a unipolar signal of "lo" or "0" level, and outputs it; When the output of the level converter 1 is "lo", a carrier detection section 2 outputs a signal indicating that the output of "1 degree" is detected, and the signal detected by the carrier detection section 2 is notified to the monitoring control board 14. It is equipped with an input/output register 3 that performs the following operations.

This carrier detection section 2 notifies the detected signal to the supervisory control board 3 via the input/output register 3, and from the supervisory control board 14 to the first interface section 12 and second interface section 13 connected in parallel. Configure so that switching can be monitored.

[For production]

In the present invention, as shown in FIG. 1, the interface units 12 and 13 are connected in parallel to the supervisory control board 4 that controls switching, and one of them is used as the active side and the other as the standby side to monitor the switching. A level converter l is provided in each of the first interface section 12 and the second interface section 13 provided in the above-mentioned manner, and after receiving the signal from the line termination device 11 and converting it into a unipolar signal, the carrier detection section In addition to ``lo'' of the unipolar signal in the carrier detecting section 2,
The presence or absence of the level is detected and output.

Therefore, by notifying the supervisory control board 14 of the signal detected by the carrier detecting section 2 via the input/output register 3, the supervisory control board 14 can switch the redundant first interface section 12 and second interface section 13 from current use to the supervisory control board 14.・
Allows for backup switching and monitoring.

〔Example〕

FIG. 2 is a diagram showing an embodiment using the circuit of the present invention. In FIG. 6, 11 is a line termination device, 12 is a first interface section, 13 is a second interface section, 14 is a supervisory control board, 15 is a line termination cable, 16 is a duplex cable, 17 is a data bus, 18 is a control bus, and 19 is a terminal device. Further, 1, 3, 4, and 5 are provided inside the active interface unit 12 and the spare first interface unit 12 and second interface unit 13, 1 is a level converter, and 3 is an input/output unit. 4 is a register, 4 is a relay driver, and 5 is a relay. The configuration and operation of these components are substantially the same as those of the conventional example. Through these connections, when the first interface section 12 is in active use, the second interface section 13 is made into a spare, and conversely, when the second interface section 13 is in active use, the first interface section 12 is made into a spare. Transmission and reception are performed between the line termination device 11 and the terminal device 19.

In the present invention, instead of the method obtained in the configuration described in the conventional example, in which the monitoring and control board 14 monitors the active/backup based on the information input by the operator at the time of initial connection, As shown in FIG. 2, a carrier detection section 2 is provided between the level converter l of the first interface section 12 and the second interface section 13 and the input/output register 3, respectively. This makes it possible to detect whether the second interface section 13 is in an active or standby operating state (hereinafter referred to as status).

FIG. 3 shows a diagram illustrating the timing of received signals and status according to the present invention. That is, Figure 3 +8
) indicates the format of the signal transmitted from, for example, the line termination device 11, and indicates that the signal is composed of one multiframe signal consisting of the 1st frame to the 12th frame. Also, Figure 3 (part 3) shows the detailed configuration of the signal of each frame shown in Figure 3 (al), which consists of the first frame bit of the frame and a 192-bit transmission signal. It is shown in Figure 3 (
C1 shows the relationship between each frame number and the bit value assigned to the beginning of the frame. For example, the first frame has a bit value of °1°, and the second frame has a bit value of °0°. is standing, and the 12th frame shows that "l" is standing.This (C1
The bit value at the beginning of each frame shown in FIG. added to. Note that each signal in FIG. 3 (Td) is shown as corresponding to each frame in FIG. 3 (al).

This carrier detection section 2 inputs each synchronization bit shown in FIG. 3(d), and the carrier detection section 2
′ is detected, the subsequent constant time T is determined by this “old g
h” level, and this “old gh” level.
If 1'' is not detected while the level is maintained, a so-called status signal, which returns to the ``Low'' level, is output. In this carrier detection section 2, a time constant is selected so that the time T is larger than the time interval of "1" included in the input signal.

Therefore, when the carrier detecting section 2 is currently in use (operating), the carrier detecting section 2 detects this synchronization bit node and
h”, and the status passes through the input/output register 3 to the control bus 18 and is sent to the supervisory control board 1.
4 will be notified. Therefore, the supervisory control board 14 can detect whether the first interface section 12 is currently in use and the second interface section 13 is on standby based on the notified "Ilight" level status.

Note that when the second interface section 13 is currently in use, the supervisory control board 14 receives the old GH level status from the carrier detection section 2 of the second interface section 13, and the second interface section 13 is in current use. It has been detected that there is

FIG. 4 (Part 1) is a circuit diagram of the carrier detection section of the present invention, where ■ is a level converter, and 2 is a multivibrator 21.
3 is an input/output register, and its output is connected to the control bus 18. input to the supervisory control board via FIG. 4 (part 2) is a time chart of the carrier detection section of the present invention. The operation of the carrier detection section will be explained below using FIG. 4 (Part 1) and FIG. 4 (Part 2).

The level converter 1 inputs the bipolar "1° or '0" bipolar signal shown in FIG. 4 (Part 2) (a) and performs level conversion processing. The unipolar “1” or “0” signal shown in part 2) is converted to the so-called TTL level. This signal in FIG. The status, which is a gate signal shown in (C) in Figure 4 (Part 2), is input from terminal Q and has a time width T determined by the time constant determined by resistance R and capacitance C. As shown in Figure 4 (Part 2), the current status is at the "old gh' level, and the time constant should always be set larger than the minimum period of 1° included in the input signal. By doing so, when the carrier detection section 2 is operating, it always operates to maintain the old ghl level.

If it becomes a reserve and is released from active duty, its status will become "Low" level after a certain period of time.

Therefore, by having the input/output register 3 notify the supervisory control board 14 of the status of this "old gh' level or °Low" level, the supervisory control board 14 can communicate with the first interface section 12 and the second interface section 13. It is possible to detect whether the line termination cable 15 is in active use or standby, and therefore it is possible to detect whether the line termination cable 15 is connected to the first line termination cable 12 or the second interface section 13.

Note that the received signal here is the signal shown in ('b) in Figure 3, and it is sufficient if the frame bit, which is the first synchronization bit, always includes 1° during the above-mentioned time interval T. Therefore, even if the received transmission data shown in FIG.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, when the operator connects the line termination cable, the supervisory control board detects the carrier included in the transmitted signal and connects the cable to either the active or standby side. be able to recognize what has been done.

Therefore, there is no need for the operator to provide information to the supervisory control board, and furthermore, it is possible to immediately recognize whether the supervisory control board is currently in use or a standby.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing the principle configuration of the present invention, FIG. 2 is a diagram showing an embodiment using the circuit of the present invention, FIG. 3 is a diagram showing the timing of received signals and status according to the present invention, Figure 4 (Part 1) is a circuit diagram of the carrier detection unit of the present invention, Figure 4 (Part 2) is a tie chart of the carrier detection unit of the present invention, and Figure 5 is a diagram showing the circuit configuration of a conventional example. . In the figure, 1 is a level converter, 2 is a carrier detection section, 3 is an input/output register, 11 is a line termination device, 12 is a first interface section, 13 is a second interface section, 14 is a supervisory control board, show. +Shi5gfi haki ↑Rear J yellow leaf %-CEI 7th l phantom diagram (portrait 1) diagram (kf ha 2)

Claims (1)

[Claims] A line termination device (11) that outputs a signal that receives data transmitted from a public communication line and converts it into a bipolar code is connected to one end, and a line termination device (11) is connected to the other end. A supervisory control board (14) for controlling switching between active and backup signals received from the device (11) is connected, and the line termination device (11) and the supervisory control board (14) are connected to each other.
4) a first interface unit (
12) and the second interface unit (13), receive data from the line termination device (11), and
a level converter (1) that converts it into a unipolar signal of ' or '0' level and outputs it; and when the output of the level converter (1) is '1', the '1'
a carrier detection unit (2) that outputs a signal indicating that the output of the carrier detection unit (2) has been detected, and an input/output register (3) that notifies the supervisory control board (14) of the signal detected by the carrier detection unit (2). The carrier detection unit (2) detects the input/output register (
3) using the signal output from the supervisory control board (1).
4) monitors switching of a first interface section (12) and a second interface section (13) connected in parallel.