JPS6022858B2 - Automatic remote fault isolation method using computer control - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a subscriber line transmission system in which terminals are connected to an in-office device via a subscriber line and a terminal device, which is installed in a remote location by computer control from the in-office device. The present invention relates to a transmission device for a subscriber transmission system and a failure point isolation method that automatically isolates failures in subscriber lines.

Currently, in order to isolate failure points in subscriber transmission equipment, subscriber lines, etc., each section is equipped with a loop setting.

This is stipulated by the CCITT recommendation, and each loop setting location is as shown in Figure 1. In FIG. 1, loop 1 indicates a loop setting in which a transmission signal from terminal 1 is looped back as a reception signal of terminal 1 (built-in to the terminal). Loop 2 indicates a loop setting in which the received signal of the terminating device 2 is looped back as a transmission signal of the terminating device 2, and loop 3 indicates a loop setting in which the output signal from the terminating device 2 is looped back as the input signal of the terminating device 2 ( built into the termination device). The loop 4 is between the subscriber line 3 and the termination device 4,
A loop setting is shown that connects the line on the receiving side of the subscriber line 3 and the line on the transmitting side of the subscriber line 3 (in the case of a 4-wire system). 1st
As shown in the figure, a terminal device 2 located remote from an in-office device 4
, subscriber line 3, and terminal device 1, the location of the fault can be identified by using loops 2 and 4. By the way, conventionally, this type of fault location has been isolated using the second method. This was done as shown in Figures and Figure 3.

Fig. 2 is a diagram for explaining a conventional method for forming loop 4, and Fig. 3 is a diagram for explaining a conventional method for forming loop 2. case,
b is the case where there are four subscriber lines. That is, in the case of setting Troop 4, as shown in FIG. After creating the loop resistance of the subscriber line 3, the loop resistance of the subscriber line 3 is measured at the in-office equipment 4 side, and the measured value is compared with the data on the recording paper in which the initial subscriber line loss value is written. 3 failures were identified. Even when setting Loop 2 on the same aircraft, track maintenance personnel go to the terminal device 2 in a remote location and
A loop is created on the terminal device 2 side by separating the terminal device 1 from the terminal device 1, and a failure of the terminal device 2 is determined based on whether a signal from the in-office device 4 can be received via the terminal device 2.
In this way, with conventional fault isolation methods, when a fault occurs, track maintenance personnel must travel to a remote location to carry out work, which increases both labor costs and economic costs. There were drawbacks. In addition, since failure recovery requires manpower, it takes a lot of time and there is a problem in that quick measures cannot be taken. Furthermore, when measuring the initial subscriber line loss setting required to determine subscriber line failure,
As shown in Figure 4 (Figure 4a shows the case where there are two subscriber lines, Figure 4b shows the case where there are four subscriber lines), in the past, track maintenance personnel went to remote areas and After setting up the loop, it was necessary for the station to measure the subscriber line loss using a measuring device and write the value on recording paper. The present invention has been made to solve the above-mentioned drawbacks of the conventional system, and it simplifies maintenance by eliminating the need for track maintainers to go to remote locations each time a test is performed. The objective is to provide a fault isolation system that also automates measurement.

Hereinafter, the present invention will be explained in detail with reference to the drawings. FIG. 5 shows an example of the basic configuration of the in-office device 4 of the present invention, in which 5 is a computer, 6 is a common bus, and 7 is an interface circuit 1, 8
is the loop setting command signal, 9 is the loop 2 setting command signal, 1
0 is a loop setting drive circuit, 11 is a DC current sending signal, 1
1' is a DC current reception signal, 12 is a loop setting completion signal,
13 is interface circuit 0, 14 is loop 2 setting completion signal, 15 is loop 2 confirmation circuit, 16 is interface circuit m, 17 is loop 2 confirmation command signal, 18 is loop 2 confirmation completion signal, 19 is loop 4 setting command signal , 20
is a loop 4 setting completion signal, 21 is an interface circuit W, 22 is a subscriber line loss signal, 23 is a loop 4 confirmation circuit, 24 is a loop 4 confirmation completion signal, 25 is an interface circuit V, 26 is an initial value setting command signal, 27 is a measured value signal, and 28 is an initial value completion signal.

Referring to Figure 5, we will first explain the division of forces.

Under the control of the computer 5 of the in-office device 4, a loop setting command signal 8 is transmitted from the common bus 6 in the computer to the interface circuit 7. The interface circuit 7 determines whether the loop setting command signal 8 is the loop 2 or the loop 4, and if it is the loop 2, turns on the loop 2 setting command signal 9. When this loop 2 setting command signal 9 is turned on, the loop setting drive circuit 10 sends out a DC current sending signal 11 to the subscriber line 3. At this time,
If the subscriber lines are not short-circuited or disconnected, the DC current reception signal 11' can be received, so the loop setting drive circuit 1
A loop setting completion signal 12 is output by converting the received signal into a logic level signal. This signal 12 is transmitted to the interface circuit 13 and transferred to the computer 5 via the common bus 6. Further, the loop setting completion signal 12 is ANDed with the loop 2 setting command signal 9 to generate a loop 2 setting completion signal 14, which is transmitted to the loop 2 confirmation circuit 15. As will be described later, the loop 2 confirmation circuit 15 next confirms loop 2. In the case of data communication, the loop 2 confirmation circuit 15 has the same transmission function as the terminal device that sends out the special pattern, and is capable of receiving the special pattern. It has built-in functions. Next, under control from the computer 5, the interface circuit 16 turns on the loop 2 confirmation command signal 17. This loop 2 confirmation command signal 17 and loop 2 setting completion signal 14
As a result, the loop 2 confirmation circuit 15 is activated and confirms the loop 2. The detailed operation of the loop 2 confirmation circuit 15 will be described later, but the loop 2 confirmation circuit 15 transfers the signal confirming the loop 2, that is, the loop 2 confirmation completion signal 18, to the interface circuit 16.
Then, it is converted into a code that can be passed through the computer, and the confirmation result of loop 2 is transferred to the computer 5 via the common bus 6.
On the other hand, when the loop setting command signal 8 specifies loop 4, the interface circuit 7 outputs the loop 4 setting command signal 1.
Turn on 9.

As a result, the loop setting drive circuit 1 is shorted as described above.
If it is other than a disconnection, the loop setting completion signal 12 is turned on, and the loop 4 setting completion signal 20 is created by this signal 12 and the loop 4 setting command signal 19. On the other hand, the loop setting completion signal 12 is transmitted to the computer 5 via the interface circuit 13 and the common bus 6. As a result, the computer 5 transmits the loop 4 confirmation command to the interface circuit 21, and at the same time reads the initially set subscriber line loss value from the computer memory and transmits the code (computer language) corresponding to this loss value to the interface circuit 21. . As a result, the interface circuit 21 converts the computer language into a digital quantity that is easily converted into an analog quantity. This digital quantity is the same value as the subscriber line loss value described above, and the interface circuit 21 transfers this subscriber line loss signal 22 to the loop 4 confirmation circuit 23. The loop 4 confirmation circuit 23 is activated by the loop subscriber line loss signal 22 and the loop 4 setting completion signal 20, and confirms the loop 4. When the confirmation of loop 4 is completed, a loop 4 confirmation completion signal 24 is sent from the loop 4 confirmation circuit 23 to the interface circuit 25.
The confirmation result is transmitted to the computer 5. Details of the loop 4 confirmation circuit 23 will be described later. Next, the setting of the initial subscriber line loss value will be explained. The subscriber line loss value setting is necessary in the case of loop 4. Therefore, when setting the initial subscriber line loss, the common bus 6 is controlled by the computer 5.
The initial setting command signal 26 together with the loop 4 setting command signal 19 is transferred from the interface circuit 7 to the loop setting drive circuit 10 and the loop 4 confirmation circuit 23 via the loop 4 setting command signal 19 . Then, by completing the setting of loop 4, the free-running oscillator in the loop 4 confirmation circuit 23 is driven, and a signal corresponding to the subscriber line loss value is counted by the counter in the loop 4 confirmation circuit 23. and measure the subscriber line loss value. The detailed operation will be described later. Thereafter, the loop 4 confirmation circuit 23 transfers the measurement value signal 27 and the initial value completion signal 28 to the interface circuit 25 in order to store the measurement result in a memo file in the computer. By adopting the configuration shown in FIG. 5, it becomes possible to check the settings of loop 2 and loop 4 and to measure the initial subscriber line loss value by computer control.

FIG. 6 shows an example of the setting operation of the loop setting drive circuit 10, subscriber line 3, terminating device 2, loop 2, and loop 4 in the in-office equipment when the subscriber line is a 4-wire system. .

Here, 29, 3 river relays, 31, 32 are detectors, 3
3 and 34 are relays, 35 and 36 are photocouplers, 39 is an output signal, four signals are received, and 47 is a sine wave transmission signal. To explain the operation, the relay 29 or 30 is operated by the loop 2 setting command signal 9 or the loop 4 setting command signal 19, and when the contact point is positioned as shown in the figure, the input side of the terminal device 2 is connected via the subscriber line 3. Relays 33 and 34 are driven via detectors 31 and 32 that detect the direct current direction between lines drawn from the midpoint of the transformer, respectively. As a result, loop 2 or loop 4 is connected to relays 33 and 34.
It is possible to form a contact switch using a contact switch. At that time, since the photocoupler 3536 will not operate unless the subscriber line 3 is short-circuited or disconnected, it is known that there is no abnormality, and the loop setting completion signal 12 is transmitted to the interface circuit 13, loop 2 confirmation circuit 15, and loop 4 confirmation circuit 23. do. Figure 7 shows the setting operation of the loop setting drive circuit 10, subscriber line 3, termination device 2, and loop 4 when the subscriber line is a two-wire system. 8 shows an embodiment of the loop 2 confirmation circuit 15 in FIG. 5, in which 37 is a pattern generator;
38 is a transmission circuit, 39 is an output signal, 40 is a received signal, 4
1 is a pattern detector.

In operation, the loop 2 setting completion signal 14 and the loop 2 confirmation command signal 17 are ANDed, and if it is data communication, the pattern generator 37 that generates a special pattern code is activated. The output of the pattern generator 37 is transmitted to a transmission circuit 38 which has the same transmission function as the termination device 2, and this world power signal 39 is transmitted to the subscriber line 3 and the termination terminal via a transformer as shown in FIGS. 6 and 7. propagated to device 2; At this time, "Terminal device 2"
Since the output signal 39 is looped by the loop 2, the output signal 39 is received as a reception signal 40 of the transmission circuit 38 via the termination device 2 and the subscriber line 3. If there is no abnormality in the terminal device 2, the pattern detector 41 detects that the received signal 40 matches the special pattern code sent from the pattern generator 37, and determines whether the received signal is good or bad. A determination is made and the result is communicated to interface circuit 16 as Loop 2 Confirm Complete signal 18. FIG. 9 shows an embodiment of the loop 4 confirmation circuit 23 in FIG. 5, where 42 is a D/A converter, 43 is an analog signal, 44 is a sine wave output signal, and 45 is a multiplier or variable gain control circuit. (AGC circuit), 46 is a buffer amplifier 1, 47 is a sine wave transmission signal, 48 is a sine wave reception signal, 4
9 is a buffer amplifier, 50 is a multiplier or AGC circuit,
51 is a rectifier, 52 is a peak detector, 53 is a bell detector 1, 55 is a running pulse generator output signal, 56 is a binary counter, and 57 is a bell detector 1.

The operation of FIG. 9 is as follows.

In the case of loop 4 division, loop 4 setting completion signal 2
0 and the subscriber line loss signal 22.
A D/A converter 42 converts the digital signal of the subscriber line loss signal 22 into an analog signal. In the case of 4-wire, a multiplier (or AGC circuit) 45 for multiplying the analog signal 43 and the sine wave output signal 44 controls the reception end of the termination device 2 to maintain a constant reception level. .

The output of the multiplier (or AGC circuit) 45 is connected to a buffer amplifier 46 with an output impedance suitable for the subscriber line 3.
A sine wave transmission signal 47 is transmitted to the subscriber line 3 through the . As a result, the sine wave reception signal 48 sent back from the subscriber line 3 via the loop 4 is received by the buffer amplifier 49. The output of this buffer amplifier 49 and the analog signal 43 are multiplied by a multiplier (or AGC circuit) 50 to obtain a constant reception level, and then the received signal is converted to a DC level by a peak detector 52 via a rectifier 51. Then, the level detector 53 determines whether the level is within a specified level range. Then, if it is within the specified level range (range that takes into account line temperature fluctuations), loop 4
The confirmation completion signal 24 is turned on. In the case of two wires, the oscillator 54 (see Fig. 7) provided in the termination device 2 sends out a sine wave signal with a constant sending bell, and the signal level is received by the buffer amplifier 49, as described above. The level is detected, and if the level is normal, the loop 4 confirmation completion signal 24 is turned on.

On the other hand, in the case of initial subscriber line loss value setting, the binary counter 56 is operated by the initial value setting command signal 26 and the free-running pulse generator output 55, and the digital signal of the counted value is sent to the D/A converter 42. When the control signal of the multiplier (or AGC circuit) 50 is varied by converting it into an analog signal, and as a result, the initial setting reception level can be detected by the level detector 57, the output of the binary calculator 56 at this time is The interface circuit 25 uses the binary signal as the subscriber line measurement value signal 27.
Transfer to.

As is clear from the above explanation, the following advantages can be obtained by the computer-controlled automatic remote call separation method of the present invention.

[11] Maintenance becomes easier because line maintenance personnel do not have to go to remote terminal equipment every time they perform a fault test.

[21] Cable loss records at the time of cable installation can be automatically recorded, eliminating the labor of measuring and recording.

[31] Since the location of the failure is determined by computer control, maintenance becomes easier.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the location of each loop to isolate the fault location, Figures 2 and 3 are diagrams explaining the conventional fault isolation method, and Figure 4 is the subscriber line loss. Figure 5 is a basic block diagram of the in-office device of the present invention, and Figure 6 is a diagram illustrating the conventional method for measuring set values. Figure 6 shows the loop setting drive circuit, subscriber line, and termination when there are 4 subscriber lines. A diagram showing a specific configuration example of the device, FIG. 7 is a diagram showing a specific configuration example of the loop setting drive circuit, subscriber line, and termination device when there are two subscriber lines, and FIG. 8 is a diagram showing a specific configuration example of the loop 2 confirmation. Diagram showing one embodiment of the circuit, No. 9
The figure is a diagram showing an embodiment of the loop 4 confirmation circuit. 1... terminal device, 2... terminal device, 3...
...Subscriber line, 4...Internal equipment, 5...Computer, 6...Common bus, 7...Interface circuit 1, 8...Loop Setting command signal, 9... Loop 2 setting command signal, 10...
...Loop setting drive circuit, 11...DC current sending signal, 12...Loop setting completion signal, 13...
...Interface circuit RO, 14...Loop 2 setting completion signal, 15...Loop 2 confirmation circuit, 16...
...Interface circuit m, 17...Loop 2 confirmation command signal, 18...Loop 2 confirmation completion signal, 19...Loop 4 setting command signal, 20...Loop 4 setting completion signal, 21... Interface circuit W, 22...
...Subscriber line loss signal, 23...Loop 4 confirmation circuit, 24...Loop 4 confirmation completion signal, 25...
Interface circuit V, 26...Initial value setting command signal, 27...Measurement value signal, 28...
Initial value completion signal. Figure 1 Figure 2 Figure 3 Figure 4 Figure 8

Claims (1)

[Scope of Claims] 1. In a subscriber line transmission system in which a terminal is connected to an in-office device via a subscriber line and a terminating device, failures in the subscriber line, terminating device, and terminal can be automatically detected by remote control using the in-office device. In order to isolate the fault between the terminal device and the terminal device, a computer is installed in the in-office device, and in response to the loop setting command signal from the computer, a loop 2 (to isolate the fault between the terminating device and the terminal device) (a loop that loops back the received signal of the terminating device as a transmitted signal) or loop 4
(a loop setting drive circuit for applying direct current to the subscriber line in order to set a loop in which the receiving line of the subscriber line is looped back to the transmitting line in order to isolate a fault between the terminating device and the subscriber line); In order to send a loop setting command signal from the computer to the loop setting drive circuit, a first interface circuit is connected directly to the common bus of the computer, and each loop setting completion signal from the loop setting drive circuit is sent to the common bus of the computer. A second interface circuit for transmission and each loop setting completion signal of the loop setting drive circuit are input, and a code or analog signal is sent to the corresponding termination device, and the signal is sent from the corresponding termination device via loop 2. Loop 2 for receiving the returned code or analog signal
a confirmation circuit, and a third circuit for sending a loop confirmation command signal to the loop 2 confirmation circuit and transmitting a loop 2 confirmation completion signal from the loop 2 confirmation circuit to the common bus of the computer.
The interface circuit temporarily stores a value equivalent to the subscriber line loss in the computer's internal memory and the computer control via the common bus, and converts it into a digital quantity that can be easily converted into a subscriber line loss value. a fourth interface circuit to convert, a loop setting completion signal from the loop setting drive circuit and a digital signal that is easy to convert into a subscriber line loss value from the fourth interface circuit;
A loop 4 confirmation completion signal is generated based on the result of measuring the line loss of the subscriber line configured via the loop 4 and comparing the measured value with a line loss value obtained by converting the digital signal from the fourth interface circuit. and a fifth interface circuit for transmitting a loop 4 confirmation completion signal from the loop 4 confirmation circuit to a common bus of a computer. The system is equipped with a detector for detecting the direction of the DC signal applied to the subscriber line from the setting drive circuit, and a loop setting circuit for setting the loop 2 or loop 4 based on the detection result of the detector. Automatic remote fault isolation method using computer control. 2. At the time of initial subscriber line loss setting, the loop 4 setting command signal from the first interface circuit drives the loop 4 setting circuit of the terminating device, and the loop 4 confirmation circuit includes the first interface circuit. A counter for operating the free-running oscillator according to an initial setting command signal from the automatic oscillator and counting the number of pulses of the automatic oscillator; and a counter for counting the number of pulses of the automatic oscillator; a variable gain transmitting/receiving amplifier for controlling the receiving input level of the amplifier, a receiving level detector for measuring the receiving level of the output signal of the amplifier, and an output level of the receiving level detector and the output level of the free-running oscillator having the same value. The computer-controlled automatic remote fault isolation method according to claim 1, further comprising a gate circuit for transferring the counted value of the counter to the fifth interface circuit. .