JPS6165546A - Transmission line monitor system - Google Patents

Abstract

PURPOSE:To mark a position having troubles by flowing a current in the direction reverse to a supply power current when the function of a basic group PCM relay transmission line is stopped, operating a relay in an intermediate relay, measuring a current value flowed from a constant voltage power source and comparing it with the current value previously measured when the transmission line is normal. CONSTITUTION:When a transmission line is normally functioning, a supply power current flows to a middle point (b) of an output transformer 1-5 from a middle point (a) of an input transformer 1-4. Consequently relays 2-3, 3-3... on each relay board are reversely biased not to act, and nodes 2-4, 3-4... of relays are opened. When the function of the transmission line stops, a current reverse to the supply power current is flowed in the transmission line, but this current will not flow to an upstream part of the point where a main circuit is disconnected. As a result, the relay will not act and the node remains opened. Then, since a current flows from a constant voltage power source 1-3 through a monitor/consultation circuit and the acting relay, the current is measured and compared with a previously measured current; therefore the position having troubles can be easily marked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a transmission path monitoring system for monitoring faults occurring in a transmission path for transmitting basic group PCM signals.

A method using a pulse trio is widely used as a monitoring method for a basic group PCM relay transmission line of 1.544 or 2.048 Mb/s.

In this method, for example, a specific pulse pattern is sent from a terminal repeater, a specified low frequency component is extracted from the output of each intermediate repeater, and the low frequency components are returned to the terminal repeater via a monitoring/meeting line. By comparing the level of the frequency component with the level measured when the transmission line is normal9, for example, at the time of construction, it is possible to locate the location of the fault.

However, in this method, when the cable of the transmission line is disconnected or the intermediate repeater stops functioning, that is, when the transmission line stops functioning, the low frequency components reflected from each intermediate repeater are transmitted to the terminal repeater. Since it does not return, it becomes impossible to locate the faulty part. .

For this reason, for example, maintenance personnel must go to the location of each intermediate repeater and manually connect the transmitting and receiving sections to configure a loopback, and it takes a considerable amount of time to locate the fault location.

Therefore, there is a need for a transmission line monitoring system that can easily locate the faulty location even when the transmission line stops functioning.

[Conventional technology]

Figure 2 (a) is an explanatory diagram of the pulse trio; Figure 2 (bl)
1 shows a block diagram of a conventional example of a transmission path monitoring system.

First, the pulse trio consists of two positive pulses and one negative pulse (
It consists of three pulses: a positive pulse trio (referred to as a positive pulse trio) or two negative pulses and one positive pulse (referred to as a negative pulse trio).

For example, as shown in FIG. 2 (al-■), there are eight types of intervals A between adjacent positive pulse trios, ranging from 11 to 4 bits, but the interval B between consecutive positive pulse trios is (3016/2
) Hz to (1005/2) Hz. There are 24 types.

Of course, the successive intervals of the next negative pulse trio have exactly the same value as the positive pulse trio (Fig. 2(a)-■
reference).

Next, when the pulse trio shown in Fig. 2(a)-■ is added to the repeater, the low frequency cutoff characteristics of the input quadrance etc. will cause the second
As shown in the figure (al-■), 2B low frequency components are obtained.

Therefore, by changing the value of interval B, the frequency can be changed from 1005Hz to 3
This means that 24 types of low frequency components up to 01611z can be obtained.

Next, when a failure occurs in any intermediate repeater of the basic group PCM relay transmission line shown in FIG. 2(b), an alarm is generated in the terminal repeater of station A, for example.

At this stage, the location of the fault has not been determined, so
Input terminal 5-IN of terminal relay device 1 of station A for orientation.
When we add the pulse trio to , it returns through two paths.

The first route is looped back at the intermediate repeaters 2 to 5 and the terminal equipment 6 of the B station, and then returns to the original A through the main line opposite to the previous one.
It is added to the terminating resistor connected to the output terminal R-0UT of the peripheral station equipment.

In the second route, a part of the low frequency components appearing on the output side of each intermediate repeater is transmitted through bandpass filters 2-1...6-1 and 5-2...・・1-2
is added to a level meter (not shown) connected to terminals 1-1 and 1-2 of the terminal equipment 1 of the A station via a monitoring/meeting line, and the reception level is indicated.

Therefore, by looking at the difference between this level and the previously measured level, the degree of deterioration of the intermediate repeater can be determined.

[Problem that the invention seeks to solve]

Locating the fault using this pulse trio is only possible when the transmission line is functioning, that is, when the intermediate repeater is operating, as the low frequency components do not return to the terminal equipment, so the fault cannot be located. .

Therefore, for example, if a disconnection occurs in the main line, monitoring/control line, or repeater and the function as a transmission line stops,
For example, maintenance personnel from the terminal station must go to all the intermediate repeaters, connect transmitters and receivers, and configure loopback circuits one by one to locate the fault. 4.

For this reason, there was a problem in that it took a long time to recover from a failed location.

[Means for solving problems]

The above problem is that when the function of the basic group PCM relay transmission line including the end station repeater and the intermediate repeater stops, the power supply current is reversed from the end office repeater using the main line in the transmission line. The relay in the intermediate repeater is operated by passing a current of This problem can be solved by using the present invention, which locates the fault by comparing it with the current value that was measured at the time.

[Function] According to the present invention, a relay is provided in a relay board that accommodates an intermediate repeater. Since the contacts of this relay are open during pulse trio reception, no current flows from the constant voltage power supply provided in the terminal relay device.

However, when the function of the transmission line stops, the above-mentioned relay is operated by passing a current in the opposite direction to the power supply current through the transmission line.

Therefore, a current flows from a constant voltage power source, and by measuring this current value and comparing it with a previously measured current value, the fault location can be easily located.

〔Example〕

FIG. 1 shows a block diagram of one embodiment of the invention.

Note that the same reference numerals refer to the same objects throughout the plan.

In Figure 1, when the transmission path is functioning normally, the power supply current flows from the midpoint a of the input voltage transformers 1-4 to the output voltage l.
-5, the relays 2-3, 3-3... in each relay board are reverse biased and do not operate, and the relay contacts 2-4, 3-4... is open.

However, when the transmission line stops functioning, a current in the opposite direction to the above-mentioned power supply current flows through the transmission line, but this current does not flow beyond the point where the main line is disconnected, so the relay does not operate and the contact remains open.

Next, current flows from the constant voltage power supply 1-3 through the monitoring/meeting line and the contacts of the operated relay, so by measuring this current value and comparing it with the previously measured current value, the fault location can be easily located. I can do things.

〔Effect of the invention〕

As explained above, in the present invention, when the function of the transmission line stops, the relay in the relay board is operated by flowing a current in the opposite direction to the feeding current, and the monitoring/meeting line and the operated contact are connected from the terminal station. By passing a current through the wire and comparing it with a previously measured value, the point of failure can be easily located.

This has the effect of being able to restore a failed location with less man-hours.

[Brief explanation of drawings]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 (al is an explanatory diagram of a pulse trio; the crest in FIG. 2) is a block diagram of a conventional example of a transmission path monitoring system. In the figure, 1 is a terminal device, 2.3 is an intermediate repeater, 1-3 is a constant voltage power supply, 2-3 and 3-3 are relays, and 2-4.3-4 is a contact point of the relay.

Claims (1)

[Claims] When the function of the basic group PCM relay transmission line including the terminal station repeater and the intermediate repeater stops, a current in the opposite direction to the feeding current is passed from the terminal station repeater using the main line in the transmission line. While operating the relay in the intermediate repeater, measure the current value flowing from the constant voltage power supply through the monitoring/meeting line in the transmission line and the contacts of the relay, and measure it in advance when the transmission line is normal. A transmission line monitoring method characterized by locating fault points by comparing them with current values.