JPH06169299A - Transmission line monitor system - Google Patents

Abstract

PURPOSE:To always monitor the fault of a transmission line by inserting loopback test data to an idle time slot used when a PCM 30 system is converted into a PCM 24 system. CONSTITUTION:A 30CH transmission line is converted into a 24CH transmission line at a 30CH/24CH converter 21. In this case, voice data are not accommodated to a prescribed time slot. Thus, an inserter 22 inserts test data generated from a test data generator 23 to the idle time slot. A comparator 24 compares data generated from the test data generator 23 with test data from the test data generator 23 through the inserter 22, the 24CH transmission line 31, a dropper 11, an inserter 12 and a 24CH transmission line 23. Then coincidence/ dissidence is discriminated. The result is accommodated in a prescribed time slot of the 30CH transmission line sent from the 24CH/30CH converter 26 by an inserter 27 and sent to the main body side equipment.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a PCM24 system and a PC.
The present invention relates to a transmission line monitoring method in a system including a conversion device for the M30 method.

[0002]

2. Description of the Related Art One of the fault monitoring points in a digital switching system is a transmission line between devices. If the expected data is not received, the transmission line between the devices is first tested. A loopback test is one method of this test.

FIG. 3 is a diagram showing a configuration of a conventional circuit of one embodiment, which corresponds to a loopback test when data is sent to a relay line and data is received from the relay line. The conventional loopback test will be described below with reference to FIG.

In FIG. 3, 41 and 42 are relay lines, 50 is a digital terminal (DT) which interfaces with the relay lines 41 and 42, and the DT 50 comprises a dropper 51, a loop switch 52 and an inserter 53.

Reference numeral 60 denotes a digital terminal controller (DTC) for controlling the DT50, which includes a dropper 61 and an inserter 62. Further, 70 is a device on the main body side. Furthermore, 81 and 82 are main body side device 70 and DTC60.
Transmission lines connecting the two, 83 and 84 are transmission lines connecting the DTC 60 and the DT 50, and 85 is a signal line connecting the DTC 60 and the DT 50.

The test of the plurality of transmission lines 81 to 84 is performed in the following procedure. When the main body side device 70 detects a failure which is considered to be caused by the transmission lines 81 to 84, such as a signal disconnection or a fixed high level of the signal, the transmission lines 81 and 82 are first tested. At this time, the test data is sent from the main body side device 70 to the DTC 60.

This data is extracted from the transmission line 81 by the dropper 61, sent to the inserter 62, placed on the transmission line 82 there, and returned to the main body side device 70. In the main unit 70,
Compare the transmitted test data with the received test data. In this case, the test data is contained in a control signal channel other than the voice channel, as will be described later, and the dropper 61 and the inserter 62 act on this specific channel.

If there is no problem with the transmission lines 81 and 82 in this test, the transmission lines 83 and 84 are tested next. At this time,
The loop switch 52 provided in the DT 50 is closed from the main body side device 70, and the dropper 61 and the inserter 62 in the DTC 60 are closed.
A signal that connects the
Sent to 60.

In the DTC 60, the signal is extracted from the transmission line 81 by the dropper 61, and the signal is passed through the signal line 85 to D
It is transmitted to the loop switch 52 in T50. After that, the test data is loaded on the transmission line 81. At this time, the test data must be loaded on a channel other than the specific channel on which the transmission lines 81, 82 were tested, as described later.

The test data placed on the transmission line 81 passes through the dropper 61 and the transmission line 83, is extracted from the transmission line 83 by the dropper 51 in the DT 50, and is sent to the inserter 53 in the DT 50 via the loop switch 52. Then, the test data is placed on the transmission path 84 by the inserter 53, received by the main body side device 70 through the inserter 62 and the transmission path 82, and compared with the transmission data.

The data used for monitoring the transmission line as described above has the structure shown in FIG. 4, and FIG.
It is a figure which shows the data structure in a 0CHx4 transmission line.
In the data configured as described above, the cycle of one frame is 125 microseconds (μs), and the cycle of one bit of data is 488 nanoseconds (ns).

As shown in FIG. 4, the 30CH transmission line has 30
4 transmission lines of CH transmission line # 0 to 30 CH transmission line # 3,
That is, it is composed of 30 CH × 4 transmission lines. 3
32 time slots numbered 0 to 31 are multiplexed in one frame of the 0CH transmission line # 0 to 30CH transmission line # 3.
The 0th control signal time slot of each of the H transmission line # 0 to 30CH transmission line # 3 contains test data for the loopback test and the control signal of each frame.

Further, the control signal of each channel is accommodated in each of the 16th control signal time slots of the 30CH transmission line # 0 to 30CH transmission line # 3. Audio data is stored in the remaining 30 time slots.

[0014]

Therefore, in the conventional transmission line monitoring method, the transmission line between the main body side device and the DTC is first tested, and then the transmission line between the DT and DTC is tested. In addition, there is a problem that the control signal channel cannot be used when testing the transmission line between the DT and the DTC.

An object of the present invention is to provide a transmission line monitoring system capable of constantly monitoring the transmission line between DT and DTC by using the PCM24 system and the PCM30 system.

[0016]

In order to achieve the above object, as shown in FIG. 1, loopback test data is extracted from a transmission line on the forward side into a digital terminal 10 which interfaces with a trunk line. Dropper 11 and
An inserter 12 for mounting the loopback test data from the dropper 11 on the transmission path on the return path side is further provided, and a digital terminal control interfaced with the digital terminal 10 via the transmission path on the outward path side and the transmission path on the return path side. In the device 20, an inserter 22 for mounting the test data generated by the test data generator 23 on the forward transmission path, and a dropper for extracting the test data output from the inserter 12 and mounted on the return transmission path. twenty five
And a comparator 24 that compares the test data from the test data generator 23 with the output of the dropper 25, and is configured to be able to constantly monitor the forward transmission path and the backward transmission path. .

Further, the loopback test data is inserted into an empty time slot when the conversion from the PCM30 system to the PCM24 system is performed.

[0018]

In the first aspect of the present invention, as shown in FIG. 1, a digital terminal 10 for interfacing with a trunk line is provided.
A dropper 11 and an inserter 12 are provided in the dropper 11, the loopback test data is extracted from the transmission path on the forward side in the dropper 11, and the loopback test data from the dropper 11 is placed on the return path in the inserter 12. I have to.

Further, a test data generator 23, an inserter 22, a comparator 24, and a dropper are provided in the digital terminal control device 20 which is interfaced with the digital terminal 10 via the forward transmission path and the return transmission path.
25 and 24CH / 30CH converter 26 and comparison result inserter 27 are provided, and inserter 22 includes a test data generator.
The test data generated in 23 is placed on the forward transmission path, the dropper 25 extracts the test data output from the inserter 12 and placed on the return transmission path, and the comparator 24 generates the test data. The test data from the device 23 and the output of the dropper 25 are compared.

Further, the loopback test data is inserted into an empty time slot when the conversion from the PCM30 system to the PCM24 system is performed. Therefore, it is possible to constantly monitor the transmission path on the outward path and the transmission path on the return path.

[0021]

[Embodiment] In the voice channel multiplexing system in digital exchange, 24 channels (24C) are set in one frame (125 μs).
PCM24 system for multiplexing H) and 30 channels (30C
H) is a PCM30 system. When both types are mixed, 30CH / 24CH conversion is required.

The most efficient method for converting 30CH / 24CH is 30CH × 4 which is the PCM30 system.
Transmission line (equipped with four 30CH transmission lines in parallel) and P
This is a method of mutual exchange with a 24CH × 5 transmission line (which has five 24CH transmission lines in parallel) which is a CM24 system. The conversion method is from the 24CH transmission line to the 30CH transmission line (FIGS. 2 to 4) or from the 30CH transmission line to the 24CH transmission line.
To the CH transmission line (FIG. 4 to FIG. 2).

FIG. 2 is a diagram showing a data structure in the 24CH × 5 transmission line of the present invention. In addition, FIG. 4 shows 30CH ×
It is a figure which shows the data structure in 4 transmission paths, and is the same as the data structure used conventionally.

As shown in FIGS. 2 and 4, in this monitoring system, the period of one frame is 125 μs, and the period of one bit of data is 488 ns. As described in the conventional example of FIG. 4, the 30CH transmission line is 30CH.
It is composed of four transmission lines # 0 to 30CH transmission line # 3, that is, 30CH × 4 transmission lines.

Note that 32 time slots numbered 0 to 31 are multiplexed in one frame of the 30CH transmission line # 0 to 30CH transmission line # 3, and 30CH transmission line # 0 to 30CH transmission line # is included.
Each 0th control signal time slot 3 contains test data for a loopback test and a control signal for each frame.

Further, the control signal of each channel is accommodated in the 16th control signal time slot of each of the 30CH transmission line # 0 to 30CH transmission line # 3. Audio data is stored in the remaining 30 time slots.

On the other hand, as shown in FIG. 2, the 24CH transmission line is composed of 24CH transmission lines # 0 to 24CH transmission line # 4.
Each of the 24CH transmission lines # 0 to 24CH transmission line # 4 is multiplexed with 32 time slots numbered 0 to 34 in one frame (125 μs). Control signal time slots are accommodated in the 16th and 16th time slots, and audio data is accommodated in 24 time slots.

However, from 30CH to 2 in the same frame
In order to convert to 4CH, as shown in FIG.
On the CH transmission lines # 0 to 24, there are eight time slots (indicated by diagonal lines in FIG. 2) in which voice data is not accommodated.

The present invention inserts loopback test data into any of the eight time slots to enable continuous monitoring of the transmission lines 83 and 84 between the DT50 and the DTC60 shown in FIG. It provides a monitoring method. The present invention will be described below with reference to the diagram showing the configuration of the circuit of one embodiment of the present invention in FIG.

In the present invention, the DT 10 comprises a dropper 11 and an inserter 12. Also, DTC20 has 30CH /
24CH converter 21, inserter 22 and test data generator
23, comparator 24, dropper 25, 24CH / 30CH converter
26 and a comparison result inserter 27.

The dropper 11 and the inserter 12 are always connected. Also, the 30CH / 24CH converter 21 has 3
The 0CH × 4 transmission line is input and the 24CH × 5 transmission line is output. Furthermore, the 24CH / 30CH converter 26 has 24
The CH × 5 transmission line is input and the 30CH × 4 transmission line is output. The transmission line monitoring method of the present invention will be described below.

30CH × 4 transmission lines are 30CH / 24CH
In the converter 21, as shown in FIG. 4 to FIG.
Converted to x5 transmission line. In FIG. 2, when the conversion of the transmission line is shown using the 24CH transmission line # 2 as an example, the time slot numbers are "0", "3", "8", "13", "16",
No voice data is accommodated in the time slots corresponding to '19', '24', and '29'.

Therefore, the test data generated by the test data generator 23 is inserted by the inserter 22 into a time slot (indicated by a grid pattern in FIG. 2) corresponding to, for example, the time slot 13 of these time slots.

The test data accommodated in the time slot 13 is extracted from the 24CH transmission line 31 by the dropper 11 and sent to the inserter 12. The inserter 12 inserts the test data into the time slot 13 of the 24CH transmission line 32.

The test data stored in the 24CH transmission line 32 is extracted from the 24CH transmission line 32 by the dropper 25 and sent to the comparator 24. In the comparator 24, the test data generator
Data generated in 23 and inserter 22, 24CH transmission line 3
1, the dropper 11, the inserter 12, and the test data from the test data generator 23 that has passed through the 24CH transmission line 32 are compared to determine whether they match or not.

This judgment result is sent from the 24CH / 30CH converter 26 by the comparison result inserter 27.
It is accommodated in the 0th time slot of a predetermined 30CH transmission line # 0 of the CH × 4 transmission line, for example, and is sent to the main body side device (not shown).

By configuring as described above, the DT
It becomes possible to constantly monitor the transmission line between C and DT,
The failure of the 24CH transmission lines 31, 32 can be immediately notified to the main body side device.

Further, as shown in the DTC 20 of FIG. 1, if the output of the comparator 24 is directly sent to the main body side device without being accommodated in the 30CH transmission line, the transmission line fault will be eliminated. Is it something that occurred between the main unit and DTC 10,
It is possible to immediately discriminate whether it has occurred between DT10 and DTC20.

[0039]

As is apparent from the above description, according to the present invention, (1) it is possible to constantly monitor a transmission line. (2) The accuracy of monitoring can be improved by accommodating different test transmission lines in a plurality of empty channels and judging whether all data match or mismatch. (3) There is an effect such that a portion where a transmission path failure has occurred can be immediately identified.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment circuit of the present invention.

FIG. 2 is a diagram showing a data structure in a 24CH × 5 transmission line of the present invention.

FIG. 3 is a diagram showing a configuration of a conventional example circuit.

FIG. 4 is a diagram showing a data structure in a 30CH × 4 transmission path.

[Explanation of symbols]

 10 is a digital terminal (DT) 11 is a dropper 12 is an inserter 20 is a digital terminal controller (DTC) 21 is a 30CH / 24CH converter 22 is an inserter 23 is a test data generator 24 is a comparator 25 is a dropper 26 is 24CH / 30CH Converter 27 is a comparison result inserter

Claims (2)

[Claims] 1. A dropper (11) for extracting loopback test data from a transmission line on the forward side in a digital terminal (10) that interfaces with a trunk line, and a loopback test from the dropper (11). An inserter (12) for mounting data on the return side transmission path is provided, and further, a digital terminal control device (20) that is interfaced with the digital terminal (10) via the forward side transmission path and the return side transmission path. The inserter (22) that puts the test data generated by the test data generator (23) on the forward transmission path, and the test data that is output from the inserter (12) and that is placed on the return transmission path. A dropper (25) for extracting the test data and a comparator (24) for comparing the test data from the test data generator (23) with the output of the dropper (25) are provided. And transmission path monitoring method being characterized in that to allow continuous monitoring of the return path transmission line. 2. The transmission line monitoring method according to claim 1, wherein the loopback test data is inserted into an empty time slot when the conversion from the PCM30 method to the PCM24 method is performed.