JPH04157857A - Subscriber line test system - Google Patents

Abstract

PURPOSE:To shorten the time of a test of a subscriber line by a line testing device by providing a means which disconnects plural subscriber lines from corresponding subscriber circuits and connects the disconnected subscriber lines to the same test line. CONSTITUTION:The subscriber circuits 11a-11n are provided with switches 12a-12n which disconnect function parts 14a-14n from the subscriber lines 15a-15n and connect them to a circuit-side testing device 16 and switches 13a-13n which disconnect the subscriber lines 15a-15n from the function parts 14a-14n and connect them to a line-side testing device 17. When the subscriber lines 15a-15n are tested, plural switches among the switches 13a-13n are connected to the side of the test line 19 at the same time and the subscriber lines 15a-15n are connected to the line-side testing device 17 in parallel. Therefore, many subscriber lines can be tested efficiently by one or a small number of testing devices.

Description

[Detailed Description of the Invention] [Summary] Regarding a subscriber line testing method for checking whether there is a failure in a subscriber line, the purpose is to shorten the time required for testing subscriber lines using a line testing device, and to test multiple subscriber lines. a switch means for disconnecting a plurality of subscriber lines from corresponding subscriber circuits and connecting the separated plurality of subscriber lines to the same test line; and simultaneously measuring the electrical characteristics of the plurality of subscriber lines connected to the test line by the switch means. The system includes a test device that measures the subscriber line to determine whether there is a failure or not, and when a failure is detected, tests each subscriber line one by one to identify the failure line.

[Industrial Field of Application] The present invention relates to a subscriber line testing method for checking whether there is a failure in a subscriber line.

[Prior Art] In general, digital exchanges use BOR5CI, which supplies telephone current to telephones and protects them from overvoltage and overcurrent.
An IT circuit (subscriber circuit) is provided for each subscriber. These subscriber circuits and subscriber lines can be separated using a switch installed in the subscriber circuit, and each subscriber circuit and subscriber line can be tested independently to determine if the subscriber circuit is malfunctioning. , it is now possible to isolate whether it is a failure of the subscriber line.

[Problem to be solved by the invention]

By the way, the above-mentioned test equipment for testing subscriber circuits and subscriber lines is generally provided with one testing equipment for a large number of subscribers, for example, for testing several thousand subscribers. One test device is provided. In the conventional subscriber line testing method, the test is carried out on a subscriber-by-subscriber basis, so there is a problem in that it takes a long time to complete the test for all subscribers.

An object of the present invention is to shorten the time required for testing subscriber lines by a line testing device.

[Means to solve the problem] FIG. 1 is a diagram explaining the principle of the present invention.

In the figure, the switch means 1 includes a plurality of subscriber lines (
For example, multiple lines among subscriber lines 19a to 19n)
are separated from the corresponding subscriber circuits 11a to 11n, and the separated plurality of subscriber lines are connected to the same test line 2.
Connect to.

The test device 3 simultaneously tests the electrical characteristics of a plurality of subscriber circuits connected to the test line 2 by the switch means 1, such as line-to-line and ground-to-ground resistance, voltage, or capacitance. Determine whether there is a line failure. Further, when the device detects a failure as a result of the test, it sequentially tests the plurality of subscriber lines one by one to find out which subscriber line is in failure.

[For production]

In the subscriber line testing method of the present invention, a plurality of subscriber lines can be connected to the same test line 2 and their electrical characteristics can be tested at the same time. Therefore, when testing a large number of subscriber lines with a small number of test devices, the total test time can be shortened.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 2 is a diagram showing a connection state between a subscriber circuit, a subscriber line, and a test device that tests them.

In the figure, each subscriber circuit 11a to 11n includes switches 12a to 12a that disconnect the functional units 14a to 14n from the subscriber lines 15a to 15n and connect them to the circuit side testing device 16.
12n and subscriber lines 15a to 15n to the functional unit 14.
Switches 13a to 13n are provided which are disconnected from the circuits a to 14n and connected to the line side test equipment 17.

Each subscriber line 15a to 15n has a telephone 18.
a to 18n are connected.

Under normal conditions, switches 12a to 12n, 13a to 1
3n is in the state shown in FIG. 2, and the subscriber circuit 1
1a to lln and corresponding subscriber lines 15a to 15
n is connected.

When testing the subscriber circuits 11a-lln, the switches 12a-12n are connected to the circuit-side testing device 16 in sequence.

In addition, when testing subscriber lines 15a to 15n,
A plurality of switches among the switches 13a to 13n are simultaneously connected to the test line 19 side, and a plurality of subscriber lines 15a to 13n are connected to the test line 19 side at the same time.
15n are connected in parallel to the line side test device 17.

Here, the subscriber circuits 11a-lln will be explained with reference to FIG.

Each subscriber circuit 11a-lln has a telephone set 18a-1.
Overvoltage/overvoltage to protect 8n circuits from overvoltage and overcurrent
Overcurrent protection circuit 20 and a power supply circuit (battery feed) that supplies call current to the telephones 18a to 18n.
21, a supervisory circuit (Supervision) that monitors loop on/off of the subscriber line; and a ringing signal sending circuit (Ringing) that sends a ringing signal etc. to the telephone set.
) 23, a 2-wire/4-wire conversion circuit 24 for converting a 2-wire subscriber line into a 4-wire digital communication path, and a codec circuit 25 for converting an analog signal into a digital signal. These circuits form the functional section 14 in FIG.
Corresponds to a to 14n.

Further, the test switch 26 connects the subscriber circuits 11a to 11n or the subscriber lines 19a to 19n to the circuit side testing device 16 or the line side testing device 17, and is similar to the switches 12a to 12n, 13a in FIG. Corresponds to ~13n.

Next, the configuration of the line side testing device 17 based on the subscriber line testing method of the present invention will be explained with reference to FIG.

This figure shows the configuration of a test device that tests the line-to-line and ground-to-ground resistance, voltage, and capacity of a plurality of subscriber lines.

Test lines 19A and 19B to which a plurality of subscriber lines are connected in parallel by the switches 13a to 13n described above are connected to resistance test circuits 30 and 19B via switches 27A and 27B, switches 28A and 28B, and switches 29A and 29B, respectively. A voltage test circuit 31 and a capacity test circuit 32 are connected.

When testing multiple subscriber lines at the same time, first, switches 27A and 27B are switched to the dashed line side in FIG. 4, test lines 19A and 19B are connected to resistance test circuit 30, and the resistance between the lines and between be measured. Next, switches 27A, 27B are returned to their original positions, and switches 28A, 2
8B is switched to the dashed line side (Figure 4), and test line 19
A and 19B are connected to the voltage test circuit 31, and a voltage test is performed. Furthermore, the switches 29A and 29B are on the dashed line side (
4), the test lines 19A and 19B are connected to the capacity test circuit 32, and a capacity test is performed.

FIG. 5 is a block diagram of the resistance test circuit 30. The resistance test circuit 30 is a line resistance test circuit 30 consisting of a series circuit of a resistor R and a voltage source ■, and a voltage comparison circuit (not shown).
a, a resistance-to-ground test circuit 3 consisting of a series circuit of a resistor R and a voltage source ■, and a voltage comparison circuit, and one end of which is grounded.
0b.

The line resistance test circuit 30a compares the voltage between A and B with a reference value when a constant voltage is applied to the test lines 19A and 19B via the resistor R, and compares the voltage between the lines A and B connected in parallel to the test lines 19A and 19B. It is determined whether the line resistance of the subscriber line is within a predetermined tolerance range. In addition, in the earth-to-ground resistance test circuit 30b, a resistance R is connected to the test line 19A or 19B.
Apply a constant voltage through the test line 19A and measure the voltage between the test line 19A and the ground and between the test line 19B and the ground,
These voltages are compared with a reference value to determine whether the resistance value is within an allowable range. These circuits are switched by switches (not shown), and the test lines 19A,
19B.

The above-mentioned line resistance test circuit 30a and ground resistance test circuit 3
For 0b, for example, the voltage between A and B when two normal subscriber lines are connected in parallel, the voltage between A and B and ground, or A when three subscriber lines are connected in parallel. , voltage between B, voltage between A and B and ground...
etc. are set as a reference voltage, and this reference voltage is compared with the voltage actually measured between A and B, and between A and B and the ground, and the connection connected to the test lines 19A and 19B is compared. It is determined whether the line-to-line resistance and ground-to-ground resistance of the user line are normal. This allows the line-to-line resistance and ground-to-ground resistance of multiple subscriber lines to be tested simultaneously.

FIG. 6 is a block diagram of the voltage test circuit 31. The voltage test circuit 31 includes a line voltage test circuit 31a consisting of a resistor R and a voltage comparison circuit (not shown), and one end of which is grounded.
It consists of a ground voltage test circuit 31b consisting of a resistor R and a voltage comparison circuit (not shown). These circuits are
Test lines 19A and 19B are switched by a switch etc.
It is designed to be connected to.

This line voltage test circuit 31a and ground voltage test circuit 31
In b, the line voltage and ground voltage when multiple normal subscriber lines are connected in parallel are set as reference voltages, and the actually measured line voltage and ground voltage are the reference voltages. It is determined whether the connected Kadai line is normal or not based on whether the line is within a predetermined allowable range.

Next, FIG. 7 is a block diagram of the capacitance test circuit 32.

The capacity test circuit 32 includes a line capacity test circuit 32a that checks the capacity between the test lines 19a and 19b, a test line 19a,
Ground capacitance test circuit 32 to check the capacitance between 19b and the ground
It is composed of b. Each circuit is connected to test lines 19a and 19b via switches (not shown), and by switching these switches, line-to-line or ground-to-ground capacitance is measured.

The line capacitance test circuit 32a includes a parallel circuit of a resistor R and a current source I, and a capacitance comparison circuit (not shown) that calculates the capacitance from the time it takes for the voltage of the resistor R to reach a constant value and compares it with a reference value. It consists of

The ground capacitance test circuit 32b also has the line capacitance test circuit 32a.
The circuit has a similar configuration, except that one end of the parallel circuit of the resistor R and the current source (2) is grounded.

Line capacitance test circuit 32a and ground capacitance test circuit 32b
The time required for the voltage across resistor R to reach a predetermined voltage level when multiple normal subscriber lines are connected in parallel is set as the reference value for line capacitance and ground capacitance, respectively. Whether or not the subscriber line capacity is normal is determined based on whether the actually measured line-to-line capacity and ground capacity are within predetermined tolerance ranges of reference values.

As described above, according to the above subscriber line testing method, multiple subscriber lines are connected to the same test line and the line-to-line and ground-to-ground resistance, voltage, or capacity of those lines is tested simultaneously. I can do it. Therefore, a large number of subscriber lines can be efficiently tested with one or a small number of test devices. In addition, when a line abnormality is detected, by connecting each subscriber line to the test line one by one and testing again, it is possible to find out which subscriber line is malfunctioning among multiple subscriber lines. can.

〔Effect of the invention〕

According to the present invention, the electrical characteristics of a plurality of subscriber lines can be tested simultaneously, so the line testing time can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating the principle of the present invention. FIG. 2 is a diagram showing a subscriber circuit of an embodiment and the connection state between the subscriber line and the test equipment. FIG. 3 is a block diagram of the subscriber circuit. Fig. 4 is a block diagram of the line side test equipment, Fig. 5 is a block diagram of the resistance test circuit, Fig. 6 is a block diagram of the voltage test circuit, and Fig. 7 is a block diagram of the capacity test circuit. . DESCRIPTION OF SYMBOLS 1...Switch means, 2.19A, 19B...Test line, 3...Test device.

Claims (1)

[Scope of Claims] Switching means (1) for disconnecting a plurality of subscriber lines from corresponding subscriber circuits and connecting the disconnected plurality of subscriber lines to the same test line (2); 1), simultaneously measuring the electrical characteristics of a plurality of subscriber lines connected to the test line (2),
A subscriber line testing system characterized by comprising a test device (3) that determines whether or not there is a failure in the subscriber line, and when a failure is detected, tests each subscriber line one by one to identify the failed line.