JP3486147B2 - Medium test auxiliary device for repeater and medium test method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to testing a subscriber line, and more particularly to testing a subscriber line in which a repeater is inserted.

[0002]

2. Description of the Related Art In the ISDN digital communication system, subscriber line signaling (TTC JT-G961 "Digital Transmission S
ystem on Meta11ic Local Line for ISDN Basic Route
Access ”) measures the conductor resistance and insulation resistance of the network terminator and the subscriber line by the direct current flowing through the network terminator and the subscriber line.

FIG. 1 shows a DC equivalent circuit of a network terminating device and a subscriber line. The network terminator consists of a diode DNT, a resistor RNT, and a capacitor C. DC open for positive polarity (L1> L2) and DC resistance RNT for inverted polarity (L1 <L2).
Becomes The subscriber line is composed of a subscriber line resistance RL and a subscriber line resistance Rnor. If the subscriber line has no insulation failure including short circuit, Rnor >> RL and Rnor >> RNT are established.

FIG. 2 shows the steps during the medium test.

The line terminator is disconnected from the subscriber line and the media tester is connected to the subscriber line. When measuring the insulation resistance between L1 and L2, the medium tester connects a constant voltage source (voltage V) with positive polarity (L1> L2) (Fig. 2 (1)).

At this time, the subscriber line resistance RL,
The current I1 flows through the subscriber line resistance Rnor. The medium tester calculates the insulation resistance between L1 and L2 from the current value I1 and the voltage value of the constant voltage source. In this case, V / I1 = Rnor + 2 x RL ≈ Rnor, so the media tester uses this value as the insulation resistance R between L1 and L2.
Recognized as _NOR (Fig. 2 (2)).

When measuring the conductor resistance between L1 and L2, the medium tester connects a constant current source (current value I2) with reverse polarity (L1 <L2). At this time, a current I2 flows through the subscriber line through the line resistance RL and the network terminating device internal resistance RNT. The medium tester calculates the conductor resistance from the current value I2 and the voltage value V1 between the subscriber lines. In this case, V1 / I2 = 2 × RL + RNT, so this value is recognized by the medium tester as the conductor resistance R _REV between L1 and L2 (FIG. 2 (3)).

When the test is completed, the medium tester is disconnected from the subscriber line and the line terminator is connected to the subscriber line with positive polarity (FIG. 2 (4)).

On the other hand, at present, a repeater 1 and a repeater 2 having the following functions are being studied for the purpose of extending the service application range. FIG. 3 shows a connection form example of the line terminating device, the relay 1, the relay 2, and the network terminating device.

The repeater 1 includes a network terminating unit 1 and a line terminating unit 1.
It is composed of

The repeater 2 includes a network terminating unit 2 and a line terminating unit 2.
It is composed of

The repeater 1 is installed on the side of the line terminating device on the subscriber line, and the line terminating device and the network terminating unit 1 are connected by the subscriber line 1. The interface between the line terminating equipment and the network terminating unit 1 complies with JT-G961. The line terminating unit 1 is connected to the network terminating device 2 by a subscriber line 2. The interface between the line terminating unit 1 and the network terminating device 2 has a wider service range than JT-G961.

The repeater 2 is installed on the side of the network terminating device on the subscriber line, and the line terminating unit 2 is connected to the network terminating device by the subscriber line 3. The interface between the line terminating unit 2 and the network terminating equipment complies with JT-G961.

Therefore, by inserting the repeater 1 and the repeater 2 into the subscriber line, it is possible to expand the service application range while using the conventional line terminating equipment and network terminating equipment.

[0015]

As described above, in the TTC JT-G961 system, in the prior art, the medium tester determines the insulation resistance by changing the current value flowing through the subscriber line through the network terminator to the subscriber line. And the conductor resistance is being measured, the media tester will perform a test between the media tester and the network end in the repeater if the repeater with the network end is connected to the subscriber line. It is impossible to carry out a media test between the media tester and the network terminating equipment.

FIG. 4 shows the steps during the medium test.

The line terminator is disconnected from the subscriber line and the media tester is connected to the subscriber line 1. In order to measure the insulation resistance between L1 and L2, the medium tester connects a constant voltage source with positive polarity (L1> L2). At this time, the current I3 flows through the subscriber line resistance RL1 and the subscriber line resistance Rnor1.
The medium tester calculates the insulation resistance between L1 and L2 from the current value I3 and the voltage value of the constant voltage source. In this case, V / I3 = Rnor1 + 2 x RL
Since 1 ≈ Rnor1, this value Rnor1 is L1-L2 for the media tester.
It is recognized as the insulation resistance R _NOR between them (Fig. 4 (1)).

Next, in order to measure the conductor resistance between L1 and L2,
Medium tester has constant polarity (current value I2) with reverse polarity (L1 <L2)
Connect. At this time, a current I2 flows through the subscriber line through the line resistance RL1 and the network end 1 internal resistance RNT1. The medium tester calculates the conductor resistance from the current value I2 and the voltage value V2 between the subscriber lines. In this case, V2 / I2 = 2 × RL1 + RNT1 is established, so the medium tester recognizes this value 2 × RL1 + RNT1 as the conductor resistance R _REV between L1 and L2 (FIG. 4 (2)).

When the test is completed, the medium tester is disconnected from the subscriber line and the line terminator is connected to the subscriber line with positive polarity.

As shown in FIGS. 4 (1) and 2 (2), when a medium test is performed on a subscriber line in which the repeater 1 and the repeater 2 are installed, the testable section is the medium tester and the repeater 1. It is understood that it is a section up to. However, the section in which the medium test is originally desired is the section in which the subscriber line 1, the subscriber line 2, and the subscriber line 3 are combined, that is, the section from the medium tester to the network terminator.

The present invention has been made in view of such circumstances, and an object thereof is to use a conventional medium tester for a subscriber line in which the repeaters 1 and 2 are inserted. SUMMARY OF THE INVENTION It is an object of the present invention to provide a medium test auxiliary device for a repeater and a medium test method capable of performing a test using a subscriber line and a network terminating device as a medium as usual.

[0022]

According to the present invention, each repeater is connected to a subscriber line via a repeater medium test auxiliary device (FIG. 5).

A feature of the present invention is that a medium tester is connected to one end of a subscriber line in an ISDN digital communication system in which at least one repeater is inserted, and the repeater is used to test the subscriber line. In the relay medium test auxiliary device according to claim 1, a switching unit that switches the relay to one of a communication mode and a test mode, a first positive polarity detection circuit that detects a positive voltage of the subscriber line in the communication mode, An inversion polarity detection circuit that detects an inversion polarity voltage of the subscriber line in the communication mode, a second positive polarity detection circuit that detects a positive polarity voltage of the subscriber line in the test mode, and each of the detection circuits. And a test control unit for controlling the switching unit according to the output, and a medium test auxiliary device for a repeater.

Preferably, the test control unit instructs the switching unit when all outputs of the first positive polarity detection circuit, the second positive polarity detection circuit and the inversion polarity detection circuit are turned off. Outputs a switching signal to switch to test mode.

According to another feature of the present invention, there is provided a media test method for testing a subscriber line by connecting a media tester to one end of a subscriber line in an ISDN digital communication system in which at least one repeater is inserted. , By detecting the voltage of the subscriber line to each of the repeaters ,
Direct connection between the communication mode to be connected and the input and output of the repeater.
Earned relay dexterity medium test assisting device to switch to one of the connection TEST mode, when testing the subscriber line is the absolute value than a predetermined threshold voltage to said pressurized <br/> subscriber line is small test Apply a voltage to switch the repeater to the test mode for testing, and after the test is completed, disconnect the subscriber line from the specified threshold voltage.
Switching the relay the communication mode by applying a voltage in the communication pair value is large.

Preferably, in the medium test, at least one test of an insulation resistance test of the subscriber line, a capacitance test of the subscriber line, and an external voltage test of the subscriber line is performed twice.

Preferably, the input and output of the repeater are directly connected when in test mode.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION A medium test auxiliary device for a repeater according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 6 is a block diagram showing the structure of a repeater medium test auxiliary device.

The repeater medium test auxiliary device 10 of the present invention is 12
The positive polarity detection circuit 1 and the positive polarity detection circuit 2 and the reverse polarity detection circuit 1 and the test control unit 18 and the switching unit 20. 30 is a repeater.

The positive polarity detection circuit 1 is a Zener diode Dz
1 (zener voltage Vz0), resistor Rn1, diode Dn1, and photocoupler PCn1.

The positive polarity detection circuit 2 is a Zener diode Dz
2 (zener voltage Vz0), resistor Rn2, diode Dn2, and photocoupler PCn2.

The reverse polarity detection circuit 1 is composed of a resistor Rr1, a diode Dr1, and a photocoupler PCr1.

The changeover unit is composed of a changeover switch Swt. Swt is connected to the contact Ptst by the polarity change judgment unit when the positive polarity detection signal 1 of PCn1, the positive polarity detection signal 2 of PCn2 and the inverted polarity detection signal 1 of PCr1 are all OFF, otherwise it is connected to the contact Pcom. To be done.

In the initial state, the switching unit is connected to the contact Pcom.

A case where a line terminating device is connected to the subscriber line 1 as shown in FIG. 5 will be described. At this time, the line terminating device and the line terminating unit 1 of the repeater 1
Respectively connect the power source Vc to the subscriber lines 1 and 2 with positive polarity (L1> L2) or reverse polarity (L1 <L2). The voltage value of the power source is not constant because it depends on the usage status of the subscriber line and the network terminating device, but Vc> Vz0 is a guaranteed value.
At this time, the positive polarity detection signal 1 of the photocoupler PCn1 of the positive polarity detection circuit 1 or the photocoupler PC of the reverse polarity detection circuit 1
One of the reverse polarity detection signals 1 of r1 turns ON. As a result, the test control unit holds the switching unit Swt at the contact Pcom to enter the communication mode.

The operation during the medium test will be described. 7,8,
The steps of the operation are shown in 9, 10, 11, and 12. During the medium test, the line terminating equipment connected to the subscriber line is disconnected from the subscriber line, and the medium tester is connected to the subscriber line 1 to enter the test mode (FIG. 7).

At this time, the medium tester conducts a medium test by connecting a constant voltage source (voltage V <Vz0) with a positive polarity (L1> L2) to the subscriber line polarity. The test performed here may be any of an insulation resistance test, a capacity test, and an external voltage test, but the insulation resistance test is performed here as an example.

By carrying out these tests (here, the insulation resistance test), first, the positive polarity detection signal 1 of the photocoupler PCn1 of the positive polarity detection circuit 1 of the repeater medium test auxiliary device 1,
The positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuit 2 and the reverse polarity detection signal 1 of the photocoupler PCr1 of the reverse polarity detection circuit 1 are all 0FF. As a result, the test control unit switches the Swt of the switching unit from the contact Pcom to Ptst (FIG. 8).

Next, the positive polarity detection signal 1 of the photocoupler PCn1 of the positive polarity detection circuit 1 and the positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuit 2 of the medium test auxiliary device 2 for repeater.
Also, the reverse polarity detection signal 1 of the photocoupler PCr1 of the reverse polarity detection circuit 1 is all turned off. As a result, the test control unit switches the Swt of the switching unit from the contact Pcom to Ptst (FIG. 9).

After the insulation resistance measurement is completed, the insulation resistance test is conducted again. This is because the insulation resistance of the network terminator and the subscriber line cannot be accurately measured in the first insulation resistance test because the switching operation of the switching unit is included in the test. During the second insulation resistance test, the positive polarity detection signal 1 of the photocoupler PCn1 of the positive polarity detection circuit 1, the positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuit 2 and the photocoupler PCr1 of the reverse polarity detection circuit 1 Since the inversion polarity detection signal 1 of 1 remains OFF, the test control unit holds the switching unit Swt at the contact Ptst.

At this time, for the subscriber line, the line resistance RL1 of the subscriber line 1, the line resistance Rnor1 of the subscriber line 1, and the subscriber line 2
Line resistance RL2, subscriber line 2 line resistance Rnor2, subscriber line 3 line resistance RL3, subscriber line 3 line resistance Rnor3,
A current I4 flows through. The medium tester calculates the insulation resistance between L1 and L2 from the current value I4 and the voltage value of the constant voltage source. In this case, V / I4 = 1 / (1 / Rnor1 ＋ 1 / Rnor2 ＋ 1 / Rnor3) ＋ 2 × (RL1
+ RL2 + RL3) ≒ 1 / (1 / Rnor1 + 1 / Rnor2 + 1 / Rnor3), so the media tester uses this value 1 / (1 / Rnor1 + 1 / Rnor2 + 1 / Rnor
3) is recognized as the insulation resistance R _NOR between L1 and L2 (Fig. 10).

Next, in order to measure the conductor resistance between L1 and L2,
Medium tester has constant polarity (current value I2) with reverse polarity (L1 <L2)
Connect.

At this time, the photocoupler of the positive polarity detection circuit 1
Since the positive polarity detection signal 1 of PCn1, the positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuit 2 and the reverse polarity detection signal 1 of the photocoupler PCr1 of the reverse polarity detection circuit 1 are all 0FF, the test controller Holds the switching part Swt at the contact Ptst. In addition, for the subscriber line, the line resistance RL of the subscriber line 1
1. The current I2 flows through the line resistance RL2 of the subscriber line 2, the line resistance RL3 of the subscriber line 3, and the network termination device internal resistance RNT. At this time, the line resistance RL1 for the subscriber line and the network termination unit 1
A current I2 flows through the internal resistance RNT1. The medium tester calculates the conductor resistance from the current value I2 and the voltage value V3 across the subscriber line. In this case, V3 / I2 = 2 × (RL1 + RL2 + RL3) + RNT, so this value 2 × (RL1 + RL2 + RL3) + RNT is recognized as the conductor resistance R _REV between L1 and L2 by the medium tester (FIG. 11).

As a disconnecting method, the medium tester is switched to the line terminating device. At this time, the line terminating device has a positive polarity (L1> L
Connect the power supply Vc (> VzO) at 2). As a result, the positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuits 2 of the repeater medium test auxiliary devices 1 and 2 is turned ON, and the test control unit switches the switch unit Swt from the contact point Ptst to Pcom. At this time, the positive polarity detection circuit 1 of the repeater medium test auxiliary device 1
The positive polarity detection signal 1 of the photocoupler PCn1 of 0 is 0N, the positive polarity detection signal 2 of the photocoupler PCn2 of the positive polarity detection circuit 2 and the reverse polarity detection signal 1 of the photocoupler PCr1 of the reverse polarity detection circuit 1 are OFF. The control unit switches the Swt of the switching unit to the contact Pc
Hold on om.

At this time, the repeater medium test auxiliary device 2 is connected to the line terminating portion 1 by the subscriber line 2. The line termination unit 1 has positive polarity (L1> L2) or reverse polarity
Connect the power supply Vc (> VzO) at (L1 <L2). At this time, either the positive polarity detection signal 1 of the photocoupler PCn1 of the positive polarity detection circuit 1 of the repeater medium test auxiliary device 2 or the reverse polarity detection signal 1 of the photocoupler PCr1 of the reverse polarity detection circuit 1 is turned ON.
Becomes Therefore, the test control unit switches the Swt of the switching unit to the contact Pcom.
(Fig. 12).

[0047]

According to the present invention, it is possible to perform a media test on a subscriber line in which the repeaters 1 and 2 are inserted.

[Brief description of drawings]

FIG. 1 is a DC equivalent circuit of a subscriber line and a network terminator.

FIG. 2 shows a process of media testing.

FIG. 3 shows a layout of relays.

FIG. 4 shows a test of a subscriber line in which a repeater is arranged in the prior art.

FIG. 5 shows a connection form of each device in the present invention.

FIG. 6 illustrates a media testing aid according to the present invention.

FIG. 7 illustrates switching from line terminator to media tester.

FIG. 8 shows the operation of the repeater 1 during an insulation resistance test.

FIG. 9 shows the operation of the repeater 2 during an insulation resistance test.

FIG. 10 shows a measurement mode of insulation resistance according to the present invention.

FIG. 11 shows a measurement mode of conductor resistance according to the present invention.

FIG. 12 shows the operation of the repeater when switching from the medium tester to the line terminating device.

[Explanation of symbols]

10 Media test auxiliary device 12 Positive polarity detection circuit 1 14 Positive polarity detection circuit 2 16 Reversed polarity detection circuit 1 18 Test control unit 20 Switching unit 30 repeater

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-60-16033 (JP, A) JP-A-2000-307571 (JP, A) JP-A-9-69879 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H04B 3/46-3/48 H04M 3/22-3/36 H04M 1/24-1/253

Claims (4)

(57) [Claims] 1. A relay tester for connecting a medium tester to one end of a subscriber line in an ISDN digital communication system, in which at least one relay is inserted, and which is provided in the relay station for testing the subscriber line. In the medium test auxiliary device, a switching unit that switches the repeater to one of a communication mode and a test mode, a first positive polarity detection circuit that detects a positive polarity voltage of a subscriber line in the communication mode, and a communication mode An inversion polarity detection circuit for detecting the inversion polarity voltage of the subscriber line, a second positive polarity detection circuit for detecting the positive polarity voltage of the subscriber line in the test mode, and the switching unit according to the output of each detection circuit. And a test control unit for controlling the medium, and a medium test auxiliary device for a repeater. 2. The test control unit tests the switching unit when all outputs of the first positive polarity detection circuit, the second positive polarity detection circuit and the inversion polarity detection circuit are turned off. The repeater medium test auxiliary device according to claim 1, wherein a mode switching signal is output. 3. At least one repeater is inserted
In a medium testing method for testing a subscriber line by connecting a medium tester to one end of the subscriber line in the ISDN digital communication system, the repeater is detected by detecting the voltage of the subscriber line in each of the repeaters. Is equipped with a repeater medium test auxiliary device for switching to one of a communication mode in which the relay is normally connected and a test mode in which the input and output of the repeater are directly connected, and the subscriber line is tested when the subscriber line is tested. , A test voltage with an absolute value smaller than the specified threshold voltage is applied to switch the repeater to the test mode for testing, and after the test is completed, the absolute value on the subscriber line is larger than the specified threshold voltage. A medium testing method, characterized in that a voltage during communication is applied to switch the repeater to a communication mode. 4. Repeater input and output in test mode
4. The medium testing method according to claim 3, wherein is directly connected.