JPS5820182B2 - Subscriber frequency meter circuit tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a subscriber circuit of an automatic exchange, and in particular tests the disconnection and crosstalk of a subscriber relay and a subscriber frequency meter circuit that constitute the subscriber circuit, and provides the test results. The present invention relates to a subscriber frequency meter circuit tester that visually displays .

In conventional subscriber circuit disconnection/crosstalk testing methods, the subscriber relay is tested by a tester, and the subscriber frequency meter circuit is tested by a tester between the frequency meter and the rectifier. Considering that it is a series circuit, determine in advance a value that simulates the DC resistance of the frequency meter and the rectifier, use this as a reference value, compare this reference value with the actual value of the DC resistance, and calculate the relative value. The method used was to test by having the meter indicate this, that is, by using a C line checker tester.

However, when using this test method, (1) there are differences in relays, frequency meters, rectifiers, etc. used in subscriber circuits due to variations in the characteristics of the components;
Based on differences in the subscriber circuits to be tested or due to variations in characteristics between component parts of the same subscriber circuit, the subscriber circuit and the subscriber circuit must meet the specified standard conditions. (2) Also,
The subscriber circuit is composed of a subscriber relay and a subscriber frequency meter circuit, and the subscriber relay side is connected to the negative power supply, and the subscriber frequency meter circuit side is connected to the earth. When testing the frequency meter for disconnection or crosstalk, the subscriber relay and the subscriber frequency meter circuit may interact with each other, making it impossible to conduct a sufficient test. When testing subscriber circuit relays and frequency meters for disconnection and cross-contact, it becomes necessary to add a test function for this purpose.
As a result, it is expected that the equipment will become larger and the test operations will become more complicated, resulting in an expensive equipment.

Therefore, portable small-capacity exchanges such as the CI type and C2 type automatic telephone exchanges have the disadvantage that they cannot mount components for the additional test function because there is no mounting space.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and its purpose is to normally consist of a subscriber relay and a subscriber frequency meter circuit, with the subscriber relay side connected to a negative power source. Connecting the subscriber circuit to the device according to the present invention without taking any measures such as cutting or shorting the subscriber circuit connected to the subscriber frequency meter circuit side or to the earth. , to detect disconnections and crosstalk in subscriber relays and subscriber frequency meters, and to facilitate maintenance testing of switching equipment.

That is, the present invention is a subscriber frequency meter circuit tester for testing disconnection and crosstalk between a subscriber relay and a subscriber frequency meter circuit that constitute a subscriber circuit, and which is a device having the same value as the subscriber circuit. a reference equivalent circuit section 2 having an impedance whose value can be variably set; a detection section A3 installed corresponding to the subscriber circuit; a detection section B4 installed corresponding to the reference equivalent circuit section 2; Detection part C
5 are connected in series; a detector A6 that detects the difference in the voltage drops respectively detected by the detection unit A3 and the detection unit B4; Detector B detects the difference in voltage drop
7; Discriminating the combination of presence/absence of the output of the detector A6 and the detector B7, and based on the determination result, displaying disconnection or crosstalk of the subscriber relay and the subscriber frequency meter of the subscriber circuit 10. and a judgment display control section 9: the subscriber circuit 10;
Reference equivalent circuit section 2, detection section C5, detection section B4, detection section A
3 are sequentially connected to form a loop circuit, and the detection section is connected between the connection point between the subscriber circuit 10 and the detection section A3 and the connection point between the detection section B4 and the detection section C5 related to the loop circuit. The connection point between the subscriber circuit 10 and the detection section A3 and the connection point between the reference equivalent circuit section 2 and the detection section C5 are bridged by the detector B7. The present invention is characterized in that the disconnection/crosstalk is tested by detecting balance.

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

FIG. 1 is a block circuit diagram showing an embodiment, and FIG. 2 is an embodiment showing a busy detection section of the subscriber circuit in FIG.

The busy detection unit 1 is for testing whether the subscriber circuit under test 10 is in a busy state, and is used to detect whether the subscriber circuit 10 under test is in a busy state or not. It should also be used as an introduction test section before starting the disconnection/interference test of the frequency meter.

In Figure 2, TO is an input terminal, T1 is an output terminal, and T
RO is a transistor, RO to R2 are resistors, and ZD is a constant voltage diode.

As shown in FIG. 1, the subscriber circuit under test 10 is connected to the input terminal TO via the telephone key SBY.
When it is vacant, D is connected via the contact between the subscriber relay and the telephone key SBY.
C-48V is connected.

One of the resistors RO and R1 is connected to the input terminal TO, the base of the transistor TRO is connected to the other of the resistor R1, the collector of the transistor TRO is connected to the output terminal T1, and the transistor TRO is connected to the output terminal T1.
The emitter of RO is connected to the - side of the resistor 5R2 and the anode side of the constant voltage diode ZD, and the other side of the resistors RO and R2 is connected to the DC side.
-48V and the cathode side of the constant voltage diode ZD are connected to the earth.

If the potentials with respect to the earth at the emitter of the transistor TRO and the input terminal TO are EO and El, respectively, then E
The voltage at O becomes a positive constant voltage by a voltage dividing circuit including a constant voltage diode ZD and a resistor R2.

When the subscriber circuit under test 10 is empty, the resistor RO and the subscriber relay are connected in parallel to the input terminal TO, so the relationship between EO and El becomes EO<El, and the base of the transistor TRO Current flows through the transistor TR
O turns on.

When the transistor TRO turns on, its collector current flows between the output terminal T1 and the terminal T of the judgment display control section 8 shown in FIG.
2, the transistor TR2 is ONL, and the ignition diode SBY is ignited.

Furthermore, when the subscriber circuit under test 10 is busy, the input terminal TO is at ground level, so the relationship between EO and El is E
O>El, and the transistor TRO cannot be turned on.

The reference equivalent circuit section 2 is configured to perform a test on the exchanger under test.
In addition to taking into account that there may be differences between the winding resistance values of the subscriber relay of the subscriber circuit under test 10, the rectifier of the subscriber frequency meter circuit, and the winding resistance values of the subscriber frequency meter circuit, Considering all the differences in variation, etc., selector switches MET, L, EX, etc. are used to set the reference value for the disconnection/interference test applied to the subscriber circuit under test 10, and an appropriate number of switches to be used as the reference value. It is composed of a resistor consisting of a fixed part and a variable part.

The detection section A3, the detection section B4, and the detection section C5 are each configured with an appropriate number of resistance values (not shown).

Detector A6 and detector B7 are differential amplifiers using well-known transistors, and FIG. 3 shows a circuit according to an embodiment thereof.

TO is a power supply terminal, T1 and T2 are input terminals, T3 is an output terminal, TRO to TR3 are transistors, RO to R2 are resistors, and ZD is a constant voltage diode.

The power applied to the power supply terminal TO is the earth when testing subscriber relays for disconnection or cross-circuiting, and the positive potential supplied from the power supply section 9 when testing subscriber frequency meters for disconnection or cross-circuiting. .

The power supply terminal TO is connected to the collector of the transistor TRO, one of the resistors RO and the emitter of the transistor TR3, the base of the transistor TR3 is connected to the other side of the resistor RO and the collector of the transistor TR1, and the input terminal T1 is connected to the transistor T
to the base of KO, the input terminal T2 to the base of the transistor TRI, the output terminal T3 to the collector of the transistor TR3, the emitters of the transistors TRO and TR1 to the collector of the transistor TR2, the emitter of the transistor TR2 to one of the resistors R2, The base of the transistor TR2 is connected to one side of the resistor R1 and the cathode side of the voltage regulator diode ZD.
The other one is connected to the earth.

If the collector currents of the transistors TRO, TR1, and TR2 are respectively ICo j ICt 5 IC2 in the example circuit of the detector A6 and the detector B7 in FIG. be.

If the potentials of input terminals T1 and T2 with respect to DC-48V are El and E2, respectively, when El>E2, IC0-I
C2, IC1=0 and transistor TR3 is turned off
Then, when El<E2, ■.

1-IC2, I co = O, current flows to the base of transistor TR3, and transistor TR3 is turned on.
L. Accordingly, an output appears at the output terminal T3.

The connection relationship between the detector A6 and other components of the detector B7 is as shown in FIG.
is between the detection section B4 and the detection section C5, its input terminal T2 is between the detection section A3 and the subscriber circuit under test 10, and its output terminal T
3 are respectively connected to the input terminals TO of the judgment display control section 10, and the detector BT has its input terminal T1 connected between the detection section A3 and the subscriber circuit under test 10, and its input terminal T2 connected to the detection section C5 and the reference equivalent. The output terminals T3 of the circuit sections 2 are connected to the input terminals T1 of the judgment display control section 80, respectively.

In such a connection relationship, the detector A6 is connected to the detection unit A
The voltage drops detected by the transistor TR3 and the detector B4 are received and compared by the input terminals T1 and T2, and the magnitude of the voltage drop is determined by turning on or off the transistor TR3.

In addition, the detector B7 receives the voltage drop caused by the detecting section A3 and the voltage drop detected by the mixed detecting section in which the detecting section B4 and the detecting section C5 are connected in series, respectively, at its input terminals T1 and T.
2 and compare them, and use the method described above to convert the transistor TR3.
The magnitude of the voltage drop is determined by turning on or off.

The comparison results of the voltage drops in the detector A6 and the detector B7 are respectively outputted to the determination display control section 8 from the output terminal T3.

The judgment display control unit 8 displays the disconnection or crosstalk of the subscriber relay or the subscriber frequency meter circuit based on the comparison result between the detector A6 and the detector BT, and controls the overall test according to the present invention. A circuit according to one practical example is shown.

In the same figure, TO~T2 are input terminals, CO is a capacitor, RO~R17 is a resistor, DO~D2 is a diode,
TRO~TR5 are transistors, CM, BAL, SB
Y.

XM is the light emitting diode, 5BY0, SBY' is the contact of the non-lock electric key SBY, TSTo is the contact of the non-lock electric key TST, MET, L, EX are the lock electric key, TST
, TSTA is the relay, tstO to tst5 and tst
a0 to tsta' are contact points between the relays TST and TSTA, and T is a test terminal.

The MET is the rectifier type (silicon or selenium) of the subscriber frequency meter circuit, the above is the subscriber type (single, joint A, or joint color), and the EX is an electric key for setting the exchange type.

The power supply unit 9 is for supplying stabilized power to each of the above-mentioned components.

FIG. 4 shows a circuit of one embodiment.

In the figure, TO is an output terminal, T1 is a feedback circuit terminal, T2 is a +50V DC power input terminal, TRO and TR1 are transistors, RO to R4 are resistors, and ZD is a constant voltage diode.

The output terminal TO is the emitter of the transistor TRO, the feedback circuit terminal T1 is one of the resistors R3, and the +50V DC power input terminal T2 is the resistor RO.

The base of the transistor TRO is connected to the collector of the transistor TR1 and the other of the resistor R1, the collector of the transistor TRO is connected to the other of the resistor RO, and the base of the transistor TRI is connected to the other of the resistor R3 and the other of the resistors R1 and R2. The emitter of the transistor TRI is connected to one side of the resistor R4, the emitter of the transistor TRI is connected to the other side of the resistor 6R2, the cathode side of the constant voltage diode ZD, and the anode side of the constant voltage diode ZD and the resistor R
The other end of 4 is connected to the earth.

DC +50V input power supply is resistor RO, transistor T
It becomes a constant voltage positive power source through the R01 output terminal TO, and is supplied to the detection section A.3 and the detection section B.4 through the contact tst' of the relay TST as shown in Fig. A current flows between the reference equivalent circuit section 10 and the reference equivalent circuit section 2.

Further, the constant voltage positive power source is dropped at the detection section A.3, fed back to the feedback circuit terminal T1, divided by resistors R3 and R4, and compared with the reference voltage of the constant voltage diode ZD.

However, at this time, the voltage dropped by the detection section A.3 is amplified by an amplifier composed of a transistor TR1 and a resistor R1, and applied to the base of the transistor TRO to control the emitter potential.

Since the reference voltage is held constant by the constant voltage diode ZD, the voltage at the output terminal TO also becomes constant.

Next, the operation of the present invention during testing will be explained with reference to the drawings.

FIG. 5 is a general circuit diagram according to an embodiment of the present invention, and FIGS. 6 to 10 are explanatory diagrams of the subscriber circuit 10 in normal or abnormal conditions, and L and L' are subscriber relays. ,D
and go are the rectifiers of the subscriber frequency meter circuit, and M and y are the frequency meters of the subscriber frequency meter circuit.

The test according to the present invention is started by connecting the test terminal T shown in FIG. 5 and the terminal C shown in FIGS. Tests include a cross-wire test, and a disconnection test for subscriber frequency meters.

The test operation procedure is as shown in the flowchart of FIG.

Note that the disconnection and cross-circuit tests for subscriber relays and subscriber frequency meters are the same, so they will be described below as common tests.

However, it is assumed that the electric keys EXL and MET are installed at the positions shown in FIG.

The circuit conditions in this case are (1) Let the winding resistance values of the subscriber relay and the subscriber frequency meter M be RL and RM, and let the maximum and minimum values of the allowable ranges of RL and RM be RL and RM, respectively.
(G)? RL (L) and RM (G) J RM (
L), variable resistor RV and resistors R13 and R1
The relationship between 5 and R17 is RL(G)72<R17<RL(L) RL(G)<R17+RV RM(G)/2<R15<RM(L) RM(G)<R13.

(2) The detector A6 and the detector B7 compare the potentials of the X point and the Y point, and the X point and the Z point with respect to DC-48V, respectively.

Assuming that the potentials of the X, Y, and Z points relative to DC-48V are Ex, EY, and R2, respectively, the outputs of the detector A6 and the detector B7 are as follows.

(10 The output of detector A6 appears on terminal T3 and EX>EY
0N when EX<870 OFF (b) The output of detector B7 appears on terminal T3 and EX>Ez
When O: 0FF When EX<E2: ON However, ON in this case means resistor RO or resistor R1
The output state, OF, which drives the transistor TRO through
F indicates a state in which the transistor TRO is not driven.

Further, the relationship between the set resistance values of the detection section A3, the detection section B4, and the detection section C5 is as follows: detection section C<detection section A-detection section B.

A current flows from the power supply applied to the intermediate point between the detection unit A3 and the detection unit B4 to the subscriber circuit 10 via the detection unit A3, and a current flows to the reference equivalent circuit unit 2 via the detection unit B4 and detection unit C5. Considering, the comparison of the potentials of EX and EY and EX and Ez is as follows:
3, the detection part B4, and the detection part C5 are selected such that the relationship between the detection part A-detection part B=detection part B+detection part C is ℃・
Therefore, the DC impedances of the subscriber circuit 10 and the reference equivalent circuit section 2 are compared.

DC a of subscriber circuit 10 and reference equivalent circuit section 2;

Letting the impedances be ZL and Zs, respectively, EX and E
The relationship between Y and Ez is when EY > EY > EZ, zL > zs, and when B y > E z > E z, zL = zsEY
>EZ>EX, zL<zs.

Based on the establishment of the above relationship, the following describes subscriber circuit tests during normal conditions and abnormalities.

Detection operations for subscriber frequency meter circuit cross-wire testing, subscriber frequency meter circuit disconnection test, subscriber relay kneading test, and subscriber relay disconnection test will be explained with reference to the drawings.

(1) Subscriber circuit test under normal conditions (Figures 5 and 6) The test circuit is connected to the earth via contact tst 1 of relay TST - relay electrical contact tst ' - detection unit A - telephone key SBY
Contact 5BY0 - Test terminal T - Subscriber circuit terminal C - Current flowing through the circuit of the subscriber relay battery (CD-48■)
Hereinafter, it will be referred to as "■1".

), earth to relay contact tst l - detection part B - detection part C - variable resistor RV - resistor R17 - battery (DC-4
8V) current flowing through the circuit (hereinafter referred to as "■2").

), a voltage drop occurs in the IIX detection section A, I2X detection section B, and I2X detection section C.

Now, in the initial stage when the resistance value of the variable resistor RV is gradually increased from the minimum value to the maximum value (Rv + R17
), BL, EX, EY, and EZ with respect to the respective potentials are examined as follows.

BL> (RV+R17), I KI 2, EX>EY
>EZ Therefore, in this relationship, the outputs of the detector A6 and the detector BT are ON (present) in the detector A and 0FF (absent) in the detector B.

Therefore, a current flows to the base of the transistor TRO by the output of the detector A, turning the transistor TRO ON and turning the transistor TR1 OFF, so that the light emitting diode BAL cannot be ignited.

However, in the transient stage when the variable resistance value is further increased, the current in ■2 decreases as the resistance value increases, and Ex
, EY, and EZ with respect to their respective potentials are EY>EX>Ez.

As a result, detector A and detector B do not show any output and are ON.
Transistor TRO in state 0FFL, resistor R2
A current flows through the base of the transistor TRI due to the ground air passing through the relay contact tst'', and the light emitting diode BAL is ignited.

Ignition of the light emitting diode BAL means that the resistance value of the subscriber relay has become equal to the resistance value of the reference equivalent circuit section (RV+R17).

Hereinafter, this state will be referred to as "equilibrium." If the equilibrium point is found, the disconnection/crosstalk test of the subscriber relay will be satisfactory due to the relationship RL(G)72<R17<RL(L) as defined in the above explanation.

When the resistance value of the variable resistor RV is further increased, the current in (2) decreases as the resistance value increases, and EX, E
The correlation between the potentials of Y and EZ is E y > E z > E

In this test, since the light emitting diode BAL ignited, it was judged that the subscriber relay, that is, the subscriber relay disconnection/crosstalk test was successful. When proceeding to the test for wire breakage or crosstalk, the variable resistor RV fixes the resistance value at the position where the light emitting diode BAL lights, and operates the telephone key TST while maintaining the balance between the subscriber relay and the reference equivalent circuit section 2. to operate the relay TST, detecting section A3 and detecting section B.
4. Switch the power supply supplied to the detector A6 and the detector B7 from the earth to the positive voltage generated by the power supply section 9.

Here, to explain the above-mentioned "equilibrium", the resistance value of the variable resistor RV is changed and the resistance value is increased.
・The relationship between EX, EY, and EZ changes as follows.

(1) EX>EY>EZ...RL>Rv+R2
1 (2) EY>EX>EZ・・・R,=RV+R
21(3) EY>EZ>EX・・・RL<R
V+R21 (1) to (2) and light emitting diode B
Immediately after the AL ignites, and immediately before the variable resistor RV is further increased and the process shifts from (2) to (3), the equilibrium conditions are different and an error occurs.

Now, if the resistance value of the variable resistor RV immediately after the light emitting diode BAL ignites is RVI, the resistance value immediately before it goes out is RM2, and its increase is △R■ (=RV2-RV1), the subscriber relay winding resistance RL and (RV+R of the reference equivalent circuit section 2)
17) is ΔRV at the maximum, but the resistance value of the detection section C5 is a sufficiently small value compared to the detection section B7 and the subscriber relay winding resistance RL, so the error does not affect the test accuracy much.

However, since the resistance value of the detection part C5 determines the ignition range of the light emitting diode BAL with respect to the change in the resistance value of the variable resistor RV, if the resistance value of the detection part C5 is too small, the resistance value of the variable resistor RV A slight change in the resistance value of the light emitting diode BAL causes the light emitting diode BAL to change from lighting to extinguishing.

Therefore, balancing operation is not easy.

On the other hand, if it is thick, it is easy to perform the balancing operation, but the error increases.

The decision was made with these considerations in mind.

As described above, when balance is achieved with the variable resistor RV and the normality of the subscriber relay is confirmed, the telephone key TST is operated.

The relay TST is operated by operating the electric key TST, and the output of the detector A6 is connected to the transistor T at the contact point tst2 of this relay.
It is disconnected from the base of the RO, leaving only detector B7.

The collector of the transistor TRO is the relay contact tst 3
and tsta2, and are connected to the base of the transistor TR3 via a resistor R4 and a diode D2.

On the other hand, the output circuit of the power supply section 9 is connected to the detection section A6 and the detection section B7 by the relay contact tst'.

Further, the point X is connected to the feedback circuit of the power supply unit 9 via the relay contact tstO, and has a constant potential.

At this time, the above-mentioned error becomes the difference between the winding resistance RL of the subscriber relay and the resistance (RV+R17) of the reference equivalent circuit section 2, which affects the comparison between the winding resistance RM of the subscriber frequency meter and the resistor R15. , the resistance value of the detection part C5 is suppressed to such an extent that it does not affect this comparison.

Now, assuming that the subscriber circuit 10 is normal, RM>
R15 Therefore, EX > E z and no output appears on detector B7, and resistors R2 and R4 and capacitor CO
After a certain period of time, the transistor TR3 is
The base current flows through the transistors TR3 and TR4, which indicates that the ONL subscriber power meter circuit cross-wire test is good.The light emitting diode Move on to circuit disconnection test 1.

When relay TSTA operates, relay contact tsta0. tstal disconnects detector B7 from the base of transistor TRO and connects detector A6 instead.
is connected to the base of transistor TRO, and EX and EY
Compare the potentials of

Further, the reference resistance is switched from R15 to R13 by relay contact tsta3.

As in the case of the subscriber frequency meter circuit cross-wire test, it is assumed that the subscriber frequency meter circuit is normal, so RM<R13 Therefore, EX
<EY, so no output appears on detector A, and transistor TRO is 0FFL. Current flows to the base of transistor TR5 via resistor R2, relay contact tsta2, and resistor R11, and transistor TR5 conducts ONL subscriber frequency meter circuit disconnection test. The light emitting diode CM, which means good, lights up.

This completes all normal tests for the subscriber circuit.

(2) During the subscriber frequency meter circuit cross-wire test (Figures 5 and 9), the winding resistance of the subscriber frequency meter is RM, the winding resistance of the other subscriber frequency meter that has been crossed is RM', and the above RM is If the resistance value of the composite winding resistance of RM' is RXM, and the maximum and minimum values of RM are RM(G) and JRM(L), respectively, then RXM is RM(L)/2<RXM<RM(G)/2 becomes.

In the case of this test, the subscriber relay is normal, so the balanced operation by the variable resistor RV and the operation of the telephone key TST are (1).
Since this is the same as the previous section, it will be omitted, and only the detection and determination operations will be explained.

When the combined resistance value RXM of the winding resistance of the subscriber frequency meter is compared with the reference resistance R15, the relationship RXM<RM(G)72<R15 is established, so E.sub.X<E.sub.z.

Therefore, as can be seen from the above description, the output of the detector B is ON and the transistor TR4 is OFF, so the light emitting diode XM cannot be ignited and the subscriber frequency meter circuit is cross-wired.

Also, because the l transistor TR4 is OFF, the relay TST
Since A cannot operate, the light emitting diode CM does not ignite.

Therefore, if the light emitting diodes CM and XM are not ignited after approximately 500 m5 has elapsed after the key TST was operated, it is determined that the subscriber frequency meter circuit is cross-wired, and the test is terminated.

(3) During subscriber frequency meter circuit disconnection test (Figures 5 and 10) The winding resistance of the subscriber frequency meter becomes infinite.

In the case of this test, the subscriber relay is normal, so the balanced operation by variable resistor RV is the same as in section (1), and R
Since CM>R15, in the subscriber frequency meter circuit cross-wire test, EX>Ez, and the light emitting diode XM ignites.

In this case, the relay TSTA also operates and the subscriber frequency meter circuit disconnection test is started.

Since the relationship between RCM and R15 is RcM>R15, EX
>EY, an output appears on detector A, and transistor T
R5 is turned OFF.

Therefore, the light emitting diode CM does not ignite.

Therefore, when the light emitting diode XM ignites approximately 500 m5 after the key TST is operated and the CM does not ignite, it is determined that the subscriber frequency meter circuit is disconnected and the test is terminated.

(4) At the time of subscriber relay cross-wire test (Figures 5 and 7), the winding resistance of the subscriber relay is RL, the winding resistance of the other subscriber relay that has been crossed is RL, and the combined winding of the above RL and Rb2 If the resistance value of the resistor is RXL, and the maximum and minimum values of RL are RL(G)tRL(L), then RXL is RL(L)/2 < RXL < RL(G)/2, and the subscriber relay is balanced. In the operation that takes RXL<R17≦
It becomes R17+RV.

Further, the relationship among EX, EY, and R2 is always EX<EY<EZ.

Therefore, the outputs of detector A6 and detector B7 are OF
F, ON, even if the variable resistor RV is varied from the minimum value to the maximum value, the light emitting diode BAL cannot be ignited, and it is determined that there is a subscriber relay cross-circuit fault.

(5) During the subscriber relay disconnection test (Fig. 5, Fig. 8) The winding resistance of the subscriber relay becomes infinite, and the variable resistor is
Even if the angle is varied, E
, becomes OFF.

Therefore, the light emitting diode BAL cannot be ignited, and it is determined that the subscriber relay is disconnected.

The above explanation is based on a type of exchange in which a subscriber relay and a subscriber frequency meter circuit are normally connected.

In exchanges in which the subscriber relay and subscriber frequency meter circuits are separated during normal times, only the subscriber frequency meter is subject to testing, so there is no need to perform balanced operation, which is a test of the subscriber relay, and the power key is turned off. Set on the side.

In addition, the subscriber relay type and the subscriber frequency meter circuit rectifier type can be selected using the electric keys EX and MET, respectively, and the detection operations etc. in that case are described in (1) to (5) above.
is exactly the same.

As explained above, the present invention is a tester that performs a detection test for disconnection and cross-wire faults in subscriber relays and subscriber frequency meter circuits in subscriber circuits of automatic exchanges. The impedance of the circuit and the reference equivalent circuit section equivalent to the subscriber circuit of the exchange are compared, and the comparison results are visually displayed using light emitting diodes, so when determining the test result from the reading of the meter using a conventional tester etc. It has higher judgment accuracy and is easier to operate than the conventional tester, and can also be used to test switching systems in which the subscriber relay and subscriber frequency meter circuit are connected during normal operation, as well as testing the relay itself. There are advantages such as being able to

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of the present invention, FIG. 2 is an embodiment of a busy detection section of a subscriber circuit, FIG. 3 is a detection circuit of an embodiment of the detector, and FIG. 4 is a block circuit diagram of an embodiment of the present invention. A circuit diagram of an embodiment of the power supply section, FIG. 5 is a general circuit diagram of an embodiment of the present invention, and FIGS.
FIG. 10 shows a state transition circuit of the subscriber circuit, and FIG. 11 shows a flowchart showing one embodiment of the test order. In the figure, 1 is a busy detection section, 2 is a reference equivalent circuit section, and 3 is a busy detection section.
is the detection part A, 4 is the detection part B, 5 is the detection part C16...
...Detector A, 7 is detector B, 8 is judgment display control section, 9
1 represents a power supply unit, and 10 represents a subscriber circuit.

Claims (1)

[Claims] 1. A subscriber frequency meter circuit tester that tests disconnection and crosstalk between the subscriber relay and the subscriber frequency meter circuit that constitute the subscriber circuit, which has an impedance equivalent to that of the subscriber circuit, and whose value A reference equivalent circuit section 2 capable of variably setting; a detection section A3 installed corresponding to the subscriber circuit; a detection section B4 and a detection section C5 installed corresponding to the reference equivalent circuit section 2 are connected in series. a mixing detection section; the detection section A3;
and a detector A6 that detects the difference between the voltage drops respectively detected by the detection unit B4; a detector B7 that detects the difference between the voltage drops respectively detected by the detection unit A3 and the mixed detection unit; the detector A6 and a determination display control section 9 that determines the combination of the presence or absence of the output of the detector B7 and, based on the determination result, displays disconnection or crosstalk of the subscriber relay and the subscriber frequency meter of the subscriber circuit 10. Provision; the subscriber circuit 10
, the reference equivalent circuit section 2, the detection section C5, the detection section B4, and the detection section A3 are sequentially connected to form a loop circuit, and the connection point between the subscriber circuit 10 and the detection section A3 related to the loop circuit is The connection between the detection section B4 and the detection section C5 is connected by the detector A6, and between the subscriber circuit 10 and the detection section A3.
The connection point between the reference equivalent circuit section 2 and the detection section C5 is bridged by the detector B7, and the disconnection/crosstalk is tested by detecting unbalance of the bridge. A subscriber frequency meter circuit tester characterized in that: