JP4470066B2 - Subscriber circuit test method, apparatus and program - Google Patents

Description

  The present invention relates to a test technique for a subscriber circuit, and more particularly to a test method and apparatus for an analog subscriber circuit and a program for controlling the test.

  An analog subscriber circuit of a digital exchange such as a PBX (private branch exchange) or a central office exchange has an interface between a subscriber terminal (analog terminal) such as a telephone and the inside of the digital exchange, for example, a current supply function to a subscriber line , Overvoltage protection function, call signal transmission / response detection function, subscriber line monitoring function such as call detection / end-call monitoring, subscriber line 2-wire signal and 4-wire signal conversion function, subscriber line test It has various functions such as a function to connect to a circuit.

  In order to test the analog subscriber circuit without affecting the subscriber, it is necessary to perform the test while the subscriber's analog terminal is on-hook (ON-HOOK). For this reason, in the analog subscriber circuit test, the normality of the codec function that can operate even when the analog terminal is in the on-hook state has been confirmed.

  As an analog subscriber circuit test technique, for example, Patent Document 1 discloses an encoder / decoder of a circuit device such as a subscriber circuit for accommodating an analog signal subscriber line, a trunk line, or a trunk in a digital exchange. A test scheme is disclosed. This test method is to input a test signal to the subscriber circuit and measure the level of the signal returned from the hybrid. It is a verification test of the functions up to the encoder, decoder, and hybrid. The 2-wire / 4-wire conversion function is not tested.

  Further, in Patent Document 2, in the digital exchange, the power-down state of the subscriber circuit's code decoding circuit can be released from the outside, and the telephone is on-hook and the subscriber circuit's code decoding circuit in the idle state is powered. In this state, the test sound is sent through the communication channel network and returned via the code decoding circuit and the 2-wire / 4-wire conversion circuit, thereby enabling the normality of the code decoding circuit to be confirmed. A test scheme is disclosed. This confirms the normality of the code decoding circuit by confirming that the digital test sound transmitted from the test sound generating circuit is returned to the test receiving circuit.

JP 59-229957 A JP-A-62-210769

  The conventional analog subscriber circuit test has the following problems.

  The first problem is that the DC power supply function and the 2-wire / 4-wire conversion function cannot be tested without affecting the subscriber. That is, in the test of the analog subscriber circuit, normality should be confirmed for the DC power supply function and the 2-wire / 4-wire conversion function, which are functions closer to the subscriber terminal side, but the subscriber terminal (telephone) When the is in the on-hook state, a DC loop is not formed between the analog subscriber circuit and the telephone, so the DC power supply function and the 2-wire / 4-wire conversion function of the analog subscriber circuit do not operate, and normality can be confirmed. Can not. On the other hand, in order to confirm the normality of the analog subscriber circuit DC power supply function and the 2-wire / 4-wire conversion function, it is necessary to connect a test device to the subscriber line, which affects the subscriber. End up.

  The second problem is that the failure detection range of the analog subscriber circuit is narrow due to the first problem. If there is a failure other than the codec function, the failure is known only when the subscriber calls.

  Therefore, a main object of the present invention is to provide a method, an apparatus, and a program capable of confirming the normality of functions closer to the subscriber terminal side in the analog subscriber circuit.

  In order to solve the above-described problems, the invention disclosed in the present application is generally configured as follows.

According to one aspect of the present invention, when a subscriber terminal is in an on-hook state, the DC power supply unit and the 2-wire / 4-wire conversion unit of the analog subscriber circuit corresponding to the subscriber terminal are made operable. Then, a test signal is sent to the analog subscriber circuit,
Determining the level of a return signal (also referred to as an “echo return signal”) that is looped back in the analog subscriber circuit;
Based on the determination result of the level of the return signal, whether or not the functions of the analog subscriber circuit including the DC power feeding unit and the 2-wire / 4-wire conversion unit are normal, and the analog subscriber circuit When the function is not normal, it is possible to identify an abnormal part.

In the method according to the present invention, the level of the return signal is
(A) The test signal sent to the analog subscriber circuit reaches the 2-wire / 4-wire conversion unit and the DC power supply unit in the analog subscriber circuit, and is returned at the DC power supply unit. Return signal level,
(B) The level of a signal obtained by canceling echo in the hybrid part from the test signal,
(C) No return signal level
To determine which of the
In the case of (A), the analog subscriber circuit is normal. In the case of (B), the DC power supply unit or the 2-wire / 4-wire conversion unit in the analog subscriber circuit is faulty. It is determined that the codec unit in the analog subscriber circuit is faulty.

In the method according to the present invention, when the subscriber terminal is in an on-hook state, the DC power supply unit and the 2-wire / 4-wire conversion unit of the analog subscriber circuit corresponding to the subscriber terminal are made operable. Send the signal to the analog subscriber circuit,
The level of the return signal returned in the analog subscriber circuit is detected at a predetermined first level, and if the signal is not detected, it is determined that the codec unit in the analog subscriber circuit is faulty. And
On the other hand, if a signal is detected, send a test signal to the analog subscriber circuit,
The level of the return signal returned in the analog subscriber circuit is detected at a predetermined second level, and when a signal is detected, the DC power supply unit in the analog subscriber circuit and the 2 It is determined that the line / 4-wire conversion unit is faulty,
If no signal is detected, the analog subscriber circuit may be determined to be normal.

  According to another aspect of the present invention, when a subscriber terminal is in an on-hook state, the apparatus controls activation of a DC power feeding unit and a 2-wire / 4-wire conversion unit of an analog subscriber circuit corresponding to the subscriber terminal. A test control unit for controlling the test of the analog subscriber circuit in a state where the terminal is on-hook, a signal transmission unit for transmitting a test signal to the analog subscriber circuit by control from the test control unit, and the analog A level determination unit that determines a level of a return signal that is returned after the test signal transmitted to the subscriber circuit returns in the analog subscriber circuit, and notifies the test control unit of the determination result. The test control unit specifies whether or not the analog subscriber circuit is normal based on the determination result of the level determination unit, and if it is not normal, identifies the location that is not normal.

In the apparatus according to the present invention, the test control unit, based on the determination result of the level of the return signal in the level determination unit, the level of the return signal,
(A) The test signal transmitted to the analog subscriber circuit reaches the 2-wire / 4-wire conversion unit and the DC power supply unit in the analog subscriber circuit and is turned back by the DC power supply unit to be normal. Return signal level, which has returned to
(B) The level of a signal obtained by canceling echo in the hybrid part from the test signal,
(C) No return signal level
To determine which of the
In the case of (A), the analog subscriber circuit is normal. In the case of (B), the DC power supply unit or the 2-wire / 4-wire conversion unit in the analog subscriber circuit is faulty. A configuration may be adopted in which it is determined that the codec unit in the analog subscriber circuit is faulty.

  In the apparatus according to the present invention, when the subscriber terminal is in the on-hook state, the DC power supply unit and the 2-wire / 4-wire conversion unit of the analog subscriber circuit corresponding to the subscriber terminal are activated and controlled. A test control unit that controls the test of the analog subscriber circuit in a state; a signal transmission unit that sends a test signal to the analog subscriber circuit by control from the test control unit; and a control from the test control unit And a signal detection unit in which the signal detection level is variably set, and the signal detection unit detects a return signal returned in the analog subscriber circuit at a set signal detection level, and Based on the presence or absence of signal detection in the signal detection unit, the test control unit determines whether the analog subscriber circuit is normal or not, and if not normal, identifies a location that is not normal Good.

In the apparatus according to the present invention, the test signal is sent to the analog subscriber circuit, and the level of the return signal returned in the analog subscriber circuit is set at a first level predetermined by the signal detector. Detect
When no signal is detected by the signal detection unit, the test control unit determines that the codec unit in the analog subscriber circuit is faulty,
When a signal is detected by the signal detection unit, the test control unit controls the signal transmission unit to send a test signal to the analog subscriber circuit,
A level of a return signal returned in the analog subscriber circuit is detected at a second level by the signal detector;
When no signal is detected by the signal detection unit, the test control unit determines that the DC power supply unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit are faulty,
When no signal is detected by the signal detection unit, the test control unit may determine that the analog subscriber circuit is normal.

In the computer program according to another aspect of the present invention, when the subscriber terminal is in an on-hook state, the DC power supply unit and the 2-wire / 4-wire conversion unit of the analog subscriber circuit corresponding to the subscriber terminal are operable. A process of controlling the analog subscriber circuit to send a test signal from a signal transmission unit;
Function including the DC power supply unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit based on the level determination result in the level determination unit that receives the return signal returned in the analog subscriber circuit And a program for causing the computer of the test control apparatus to execute a process of identifying a location that is not normal.

When the subscriber terminal is in an on-hook state, the computer program according to the present invention puts the DC power supply unit and 2-wire / 4-wire conversion unit of the analog subscriber circuit corresponding to the subscriber terminal into an operable state, A process of setting a predetermined first level and transmitting a test signal from the signal transmission unit to the analog subscriber circuit;
As a result of detecting the level of the return signal returning in the analog subscriber circuit at the first level by the signal detection unit, if the signal is not detected, a failure of the codec unit in the analog subscriber circuit A process of determining,
When a signal is detected, a process of setting a predetermined second level in the signal detection unit and sending a test signal from the signal transmission unit to the analog subscriber circuit;
When a signal is detected as a result of detecting the level of the return signal returning in the analog subscriber circuit at the second level by the signal detection unit, the DC power supply unit in the analog subscriber circuit and The program comprises a program for causing the computer of the test control apparatus to execute a process of determining that the analog subscriber circuit is normal when it is determined that the 2-wire / 4-wire conversion unit has failed and no signal is detected.

  According to the present invention, the test signal is sent to the analog subscriber circuit, and the sent / outgoed test signal is turned back in the analog subscriber circuit to determine whether the test signal is normal / failed. The normality of the function closer to the subscriber terminal side in the analog subscriber circuit (DC power supply unit, 2-wire / 4-wire conversion circuit) can be confirmed. According to the present invention, a failure location can be detected early by widening the failure detection range.

  Embodiments will be described with reference to the accompanying drawings to describe the present invention in more detail. FIG. 1 is a diagram showing the configuration of the first exemplary embodiment of the present invention. First, the operation principle of the present invention will be described.

  The test control unit 1 has a DC power supply unit 11, an activation control function of the 2-wire / 4-wire conversion unit 15, a control monitoring function of the signal transmission unit 2, and a control monitoring function of the level determination unit 4. From the result of the level of the echo return signal received in step 1, the normal / failure determination and the failure location are identified. Under the control of the test control unit 1, the DC power supply unit 11, the 2-wire / 4-wire conversion unit 15 are made operable when the telephone 5 is in an on-hook state, a test signal is sent to the analog subscriber circuit 10, and the analog subscriber The level of the echo return signal returned in the circuit is determined.

  In the present invention, when the telephone 5 is in an on-hook state, the DC power supply unit 11, the 2 wire / 4 wire conversion unit 15 is activated, the test signal is transmitted, and the level of the echo return signal returned in the analog subscriber circuit 10 is set. By determining, the normality of the function at a location closer to the subscriber terminal is confirmed and the failure location is specified. As a result, the failure detection range is expanded and the quality of the analog subscriber circuit is enhanced.

  Referring to FIG. 1, in the first embodiment of the present invention, an analog subscriber circuit 10 includes a codec unit 16 including an encoding unit 14 and a decoding unit 13, a hybrid unit 12, and 2 wires / 4. A line conversion unit 15 and a DC power supply unit 11 that supplies a DC call current to the telephone 5 that is a subscriber terminal are provided. The hybrid unit 12 is matched with the impedance on the two-wire side so that the reception signal on the four-wire side in the two-wire / four-wire conversion unit 15 does not go around to the four-wire transmission side. Signal reflection in the 2-line / 4-line converter 15 is suppressed. The 2-wire / 4-wire conversion unit 15, together with the hybrid unit 12, divides the two subscriber lines into two lines for transmission and two lines for reception.

  In the present embodiment, a test control unit 1, a signal transmission unit 2, a signal generation unit 3, and a level determination unit 4 are provided as test circuits for the analog subscriber circuit 10. A plurality of test circuits may be provided for a plurality of subscriber lines so that parallel tests can be performed. Alternatively, one test circuit may be provided in the digital exchange, and the corresponding analog subscriber circuit 10 may be provided when testing a subscriber line. It is good also as a structure connected.

  The test control unit 1 has a startup control function of the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15, a control monitoring function of the signal transmission unit 2, and a control monitoring function of the level determination unit 4.

  The activation control function of the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15 is used in a so-called no-ringing service (a service that performs meter reading (remote meter reading) of meters such as electricity, water, and gas over a telephone line). Even when there is no DC loop with the telephone 5 (the telephone 5 is in an on-hook state), signal transmission (on-hook transmission) is possible. In this case, the signal is folded at the path 11-1 of the DC power supply unit 11.

  The level determination unit 4 measures and determines the level of the echo return signal from the analog subscriber circuit 10 under the control of the test control unit 1, and transmits the level determination result to the test control unit 1. The test control unit 1 determines normality / failure based on the determination result of the echo return signal level. In the case of a failure, the failure location can be specified based on the level determination result.

  The signal generation unit 3 stores encoded digital signal data (PCM (Pulse Code Modulation) encoded data) as a test signal in a storage unit.

  The signal transmission unit 2 transmits the test signal stored in the signal generation unit 3 to the analog subscriber circuit 10 under the control of the test control unit 1.

  The decoding unit 13 decodes the encoded digital signal data into a telephone band audio signal. The digital signal from the decoding unit 13 is DA-converted by a DA (digital / analog) conversion unit (not shown) and supplied to the hybrid unit 12. An analog signal output from the hybrid unit 12 to the encoding unit 14 is AD-converted by an AD (analog / digital) conversion unit (not shown), encoded by the encoding unit 14 and output. Note that a known circuit (PCM codec) is used as the codec unit 16 including the decoding unit 13 and the encoding unit 14. Needless to say, the DA conversion unit and the AD conversion unit may be provided in the decoding unit 13 and the encoding unit 14.

  The hybrid unit 12 includes an echo path 12-3 in which an output signal from the decoding unit 13 leaks through a transformer (hybrid transformer) of the hybrid unit 12 and reaches the encoding unit 14. In the example shown in FIG. 1, a branch path (pseudo-echo path) that branches an output from the decoding unit 13 side to the encoding unit 14 side of the hybrid transformer and a signal input to the hybrid transformer in the hybrid unit 12. An erasing circuit (subtracting circuit) 12-1 for subtracting the signal from the signal 12-2 is provided. The cancellation circuit 12-1 subtracts the echo signal from the echo path 12-3 and the signal from the pseudo echo path 12-2, so that the signal canceling the echo is encoded from the output of the cancellation circuit 12-1. Is input to the conversion unit 14. The cancellation circuit 12-1 constitutes an echo canceller that cancels the hybrid echo (reflection at the 2-line / 4-line conversion unit 15) together with the pseudo echo path 12-2. The digital signal from the decoding unit 13 (digital signal before DA conversion) is input to the branch path (pseudo-echo path) 12-2, and the erasure circuit 12-1 is transferred from the hybrid transformer to the encoding unit 14. You may make it perform the subtraction of the digital signal from the input digital signal (AD converted digital signal) and the branch path (pseudo echo path) 12-2. Although not directly related to the subject matter of the present invention, the impulse response of the pseudo echo path is variably set.

  Although FIG. 1 shows an example in which the hybrid unit 12 is installed on the analog side (subscriber side as viewed from the codec unit 16), it is installed on the digital side (test control unit 1 side as viewed from the codec unit 16). It is good also as a structure. The analog subscriber circuit includes various circuits for relaying the call signal, but is not shown in FIG. 1 because it is not directly related to the subject of the present invention.

  FIG. 2 is a flowchart for explaining the operation of the embodiment of the present invention. The operation of the embodiment of the present invention will be described with reference to FIGS.

  The test control unit 1 activates the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15 of the analog subscriber circuit 10 when the telephone 5 is on-hook (S1 in FIG. 2). The test control unit 1 sets the DC power supply unit 11 to the on-hook transmission mode and switches to the loop-back (path) 11-1. At this time, a local loop is not formed with the telephone 5.

  In order to send a test signal to the analog subscriber circuit 10, the test control unit 1 controls the signal transmission unit 2, and the signal transmission unit 2 uses the test signal stored in the signal generation unit 3 as an analog subscriber circuit. 10 (S2 in FIG. 2).

  The test signal transmitted from the signal transmission unit 2 returns via the hybrid unit 12, the 2-wire / 4-wire conversion unit 15, and the DC power supply unit 11 in the analog subscriber circuit 10 (the returned signal is “ Echo return signal ”).

  The level of the returned echo return signal is determined by the level determination unit 4 (S3 in FIG. 2).

  The level determination unit 4 determines the level of the echo return signal from the analog subscriber circuit 10 and notifies the test control unit 1 of the determination result (S4 in FIG. 2).

  The test control unit 1 determines whether the determined level is a normal level or a failure level. (S5 in FIG. 2).

  When the analog subscriber circuit 10 operates normally, the test signal transmitted from the signal transmission unit 2 passes through the decoding unit 13, the hybrid unit 12, the 2-wire / 4-line conversion unit 15, and the DC power supply unit 11, and then the DC power supply unit. 11, and returns to the level determination unit 4 via the 2-line / 4-line conversion unit 15, the hybrid unit 12, and the encoding unit 14. At that time, a signal returned to the hybrid unit 12 via the DC power supply unit 11, the 2 line / 4 line conversion unit 15 is transmitted from the branch path (pseudo-echo path) 12-2 in the erasing circuit 12-1 of the hybrid unit 12. And the subtracted signal is supplied to the encoding unit 14. For this reason, the echo return signal input to the level determination unit 4 has a value attenuated by, for example, several tens of dBm from the level of the transmitted test signal. DBm is an absolute value expression based on mW, and is given by dBm = 10 log 10 (mW).

  On the other hand, when the DC power supply unit 11, the 2 wire / 4 line conversion unit 15 is out of order, the test signal from the hybrid unit 12 toward the 2 wire / 4 line conversion unit 15 and the DC power supply unit 11 is I will not return to part 12. For this reason, only the signal whose echo is canceled by the erasure circuit 12-1 of the hybrid unit 12 returns to the encoding unit 14 and the level determination unit 4. That is, in the cancellation circuit 12-1, a signal corresponding to the difference between the signal (transmission test signal) of the branch path (pseudo echo path) 12-2 of the hybrid unit 12 and the echo of the echo path 12-3 is an echo return signal. Is received by the level determination unit 4. For this reason, the level of the return echo return signal is a level attenuated by, for example, several dBm from the transmitted test signal.

  Since the signal does not pass when the codec unit 16 fails, there is no level of the echo return signal (the echo return signal from the analog subscriber circuit 10 is not detected).

  When the test of the analog subscriber circuit 10 is ended, the test control unit 1 instructs the level determination unit 4 to stop the operation (S6 in FIG. 2).

  The test control unit 1 also instructs the signal transmission unit 2 to stop signal transmission (S7 in FIG. 2).

  Finally, the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15 are set in a normal state (S8 in FIG. 2).

  In the present embodiment, the following effects can be obtained.

  The DC power supply unit 11, 2 line / 4 line conversion unit 15 is activated by the on-hook transmission technique, and the level of the echo return signal including the DC power supply unit 11, 2 line / 4 line conversion unit 15 is determined. Therefore, the normality of the function closer to the subscriber terminal can be confirmed without connecting the test device to the subscriber line side when the telephone 5 is on-hook.

  Further, the failure location of the analog subscriber circuit 10 can be specified. For example, if there is a failure in the DC power supply unit 11 or the 2-wire / 4-wire conversion unit 15 depending on the level of the echo return signal, the test signal does not return to the hybrid unit 12 and only the signal for which the echo is canceled in the hybrid unit 12 Since it returns, the level of the echo return signal is attenuated by several dBm from the transmission test signal. In addition, when the codec unit 16 fails, no signal is passed, so there is no echo return signal level. In the present embodiment, it goes without saying that the above-described control operation of the test control unit 1 may be realized by program control that operates on a computer built in the test control unit 1.

  Next, a second embodiment of the present invention will be described. FIG. 3 is a diagram showing the configuration of the second exemplary embodiment of the present invention. FIG. 4 is a flowchart for explaining the operation of the second embodiment of the present invention. Referring to FIG. 3, the level determination unit 4 in the first embodiment shown in FIG. 1 is changed to a signal detection unit 41. Other configurations are the same as those of the first embodiment.

  The present embodiment is effective when it is difficult to provide the level determination unit 4 in the first embodiment. Usually, the analog subscriber circuit 10 is connected to a signal detector 41 for detecting a tone or the like. The signal detection unit 41 can variably set and adjust the level of the signal detected by the signal detection unit 41 by software or firmware.

  In this embodiment, the signal level detected by the signal detector 41 is adjusted by changing the software or firmware that controls the signal detector 41 using, for example, the existing signal detector 41 in the analog subscriber circuit 10. You may make it do.

  The operation of the present embodiment will be described with reference to the flowchart of FIG. For ease of explanation, the signal sending unit 2 sends the test signal (PCM digital signal data) stored in the signal generating unit 3 to the analog subscriber circuit 10 at a level of −20 dBm, and the analog subscriber is sent. The level that attenuates in the circuit 10 is set to −5 to 15 dBm. When a signal of −20 dBm is sent to the analog subscriber circuit 10, the echo is turned back at a level within −25 to −35 dBm.

  In FIG. 3, since the test control unit 1 tests the analog subscriber circuit 10, the test control unit 1 activates the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15 when the telephone 5 is on-hook (FIG. 4). S21).

  Next, the test control unit 1 sets the level threshold value of the signal detected by the signal detection unit 41 to −35 dBm (S22 in FIG. 4).

  After setting the level threshold, the test control unit 1 activates the signal detection unit 41 so that the signal can be received (S23 in FIG. 4).

  In order to send a test signal to the analog subscriber circuit 10, the test control unit 1 controls the signal transmission unit 2, and the signal transmission unit 2 sends the test signal stored in the signal generation unit 3 to the analog subscriber circuit 10. Transmit (S24 in FIG. 4).

  The transmitted test signal passes through the DC power supply unit 11 and the 2-line / 4-line conversion unit 15 in the analog subscriber circuit 10, and is then erased by the erasure circuit 12-1 of the hybrid unit 12. The echo whose reflection is suppressed and attenuated returns to the signal detector 41 as an echo return signal.

  The signal return unit 41 receives the returned echo return signal, and the test control unit 1 checks whether or not the signal is detected by the signal detection unit 41 (S25 in FIG. 4).

  If the signal cannot be detected by the signal detection unit 41 (level threshold = −35 dBm), the test signal does not pass due to a failure of the codec unit 16, and therefore the level of the echo return signal is not present. The test control unit 1 determines that the codec unit 16 has failed (S26 in FIG. 4).

  On the other hand, when the signal can be detected by the signal detection unit 41, the test control unit 1 controls the signal transmission unit 2 and instructs the signal transmission stop (S27 in FIG. 4).

  Furthermore, the test control unit 1 instructs the signal detection unit 41 to stop the signal detection operation (S28 in FIG. 4).

  Next, the test control unit 1 sets the level threshold value of the signal detected by the signal detection unit 41 to a value larger than −25 dBm. In this embodiment, it is set to −24 dBm (S29 in FIG. 4).

  After setting the level threshold value in the signal detection unit 41, the test control unit 1 activates the signal detection unit 41 so that the signal can be received (S30 in FIG. 4).

  In order to send a test signal to the analog subscriber circuit 10, the test control unit 1 controls the signal transmission unit 2. The signal transmission unit 2 receives an instruction from the test control unit 1 and transmits the test signal stored in the signal generation unit 3 to the analog subscriber circuit 10 (S31 in FIG. 4).

  The test signal sent from the signal transmission unit 2 to the analog subscriber circuit 10 passes through the DC power supply unit 11, the two-wire / four-line conversion unit 15 in the analog subscriber circuit 10, and the hybrid unit 12 performs two lines. The reflection of the / 4 line conversion unit 15 is suppressed, and the attenuated echo returns to the signal detection unit 41.

  The echo return signal returned from the DC power supply unit 11, the 2-wire / 4-wire conversion unit 15, and the hybrid unit 12 is received by the signal detection unit 41, and has the test control unit 1 detected the signal by the signal detection unit 41? It is confirmed whether or not (S32 in FIG. 4).

  When a signal is detected by the signal detection unit 41 (level threshold = −24 dBm), the test signal does not return to the hybrid unit 12 due to a failure of the DC power supply unit 11 or the 2-wire / 4-wire conversion unit 15. Only the cancellation signal of the hybrid unit 12 is returned. That is, the level is attenuated by several dBm from the level of the transmitted test signal. The test control unit 1 determines that a failure has occurred in the DC power supply unit 11 or the 2 / 4-wire conversion unit 15 (S33 in FIG. 4).

  If the signal cannot be detected by the signal detection unit 41 (the signal level is −24 dBm or less), the test signal is normally turned back by the DC power supply unit 11 and the 2-wire / 4-wire conversion unit 15. . In this case, the test control unit 1 determines that the analog subscriber circuit 10 is normal (S34 in FIG. 4).

  In order to end the test of the analog subscriber circuit 10, the test control unit 1 controls the signal transmission unit 2 and instructs the signal transmission stop (S35 in FIG. 4). The test control unit 1 instructs the signal detection unit 41 to stop the signal detection operation (S36 in FIG. 4).

  Finally, on-hook transmission control is stopped (S37 in FIG. 4). In this embodiment, as in the above embodiment, the above-described control operation of the test control unit 1 may be realized by program control that operates on a computer built in the test control unit 1. is there.

  It should be noted that the disclosures of the above patent documents are incorporated herein by reference. Within the scope of the entire disclosure (including claims) of the present invention, the embodiments and examples can be changed and adjusted based on the basic technical concept. Various combinations and selections of various disclosed elements are possible within the scope of the claims of the present invention. That is, the present invention of course includes various variations and modifications that could be made by those skilled in the art according to the entire disclosure including the claims and the technical idea.

It is a figure which shows the structure of the 1st Example of this invention. It is a flowchart for demonstrating operation | movement of the 1st Example of this invention. It is a figure which shows the structure of the 2nd Example of this invention. It is a flowchart for demonstrating operation | movement of the 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Test control part 2 Signal transmission part 3 Signal generation part 4 Level determination part 5 Telephone 10 Analog subscriber circuit 11 DC power supply part 11-1 Return path 12 Hybrid part 12-1 Erasing circuit (subtraction circuit)
12-2 Branch (pseudo-echo)
12-3 echo path 13 decoding unit 14 encoding unit 15 2-wire / 4-line conversion unit 16 codec unit 41 signal detection unit

Claims (12)

A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit An analog subscriber circuit test method comprising:
When the subscriber terminal is on-hook, the DC power feeding unit is switched to an on-hook transmission mode and switched to a loop back,
A test signal is transmitted to the decoding unit of the analog subscriber circuit, and when the test signal is normal, the DC power supply unit passes through the hybrid unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit. Wrapped back and output from the encoding unit,
Determine the level of the signal output from the encoding unit,
A test method for an analog subscriber circuit, characterized in that it is determined whether a determined signal level is a normal level or a fault level . The signal that has returned to the hybrid unit through the DC power supply unit and the 2-wire / 4-line conversion unit is subtracted from the signal from the pseudo echo path in the erasing circuit of the hybrid unit, and the subtracted signal is Supplied to the encoding unit,
The signal output from the encoding unit and subjected to level determination by the level determination unit is a level attenuated by a predetermined amount from the level of the test signal,
When the DC power supply unit and the 2-wire / 4-wire conversion unit are out of order, a test signal from the hybrid unit to the 2-wire / 4-wire conversion unit and the DC power supply unit is Therefore, the level determination unit receives the signal corresponding to the difference between the transmission test signal of the pseudo echo path of the hybrid unit and the echo of the echo path in the hybrid unit elimination circuit, and determines the level. The signal level is a level attenuated by a second predetermined amount than the test signal,
Since the signal does not pass if the codec unit fails, the echo return signal from the analog subscriber circuit for the test signal is not detected,
2. The test method for an analog subscriber circuit according to claim 1 , wherein a fault location corresponding to the level is specified by detecting a level of a signal from the encoding unit . A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit An analog subscriber circuit test method comprising:
When the subscriber terminal is on-hook, the DC power feeding unit is switched to an on-hook transmission mode and switched to a loop back,
A test signal is transmitted to the decoding unit of the analog subscriber circuit, and when the test signal is normal, the DC power supply unit passes through the hybrid unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit. Wrapped back and output from the encoding unit,
A test method for an analog subscriber circuit, wherein a failure point is determined by detecting a signal output from the encoding unit based on a predetermined threshold value in a signal detection unit . In the signal detection unit, when the signal is not detected with the first threshold, it is determined that the codec unit is faulty,
The signal level threshold detected by the signal detector is set to a second threshold, a test signal is sent to the analog subscriber circuit, and the DC power feeder, the 2-wire / 4-wire converter, and the hybrid unit When a return echo return signal is detected, the test signal does not return to the hybrid unit due to a failure of the DC power supply unit or the 2-wire / 4-wire conversion unit, so only the cancellation signal of the hybrid unit is detected. Is determined to be a level attenuated by a predetermined amount from the level of the transmitted test signal, and it is determined that the DC power supply unit, the 2-wire / 4-wire conversion unit is faulty,
If the signal detection unit could not detect the signal with the second threshold value, the test signal is normally folded by the DC power supply unit and the 2-wire / 4-wire conversion unit, 4. The test method for an analog subscriber circuit according to claim 3, wherein the analog subscriber circuit is determined to be normal. A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit Analog subscriber circuit testing equipment,
A signal transmitter for supplying a test signal to the analog subscriber circuit;
A level determination unit for determining a level of an output signal of the analog subscriber circuit with respect to the test signal;
A test controller ;
With
The test control unit sets the DC power supply unit to an on-hook transmission mode and switches to a loop back when the subscriber terminal is on-hook, and the signal transmission unit transmits a test signal to the decoding unit of the analog subscriber circuit. ,
The test signal sent from the signal transmission unit to the decoding unit is normally returned by the DC power supply unit via the hybrid unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit. Output from the encoder,
The level determination unit determines the level of the signal output from the encoding unit, notifies the test control unit of the determination result,
The test apparatus for an analog subscriber circuit, wherein the test control unit determines whether the determined level is a normal level or a failure level . The signal returned to the hybrid unit via the DC power supply unit and the 2-wire / 4-line conversion unit is subtracted from the signal from the pseudo echo path in the hybrid circuit erasure circuit, and the subtracted signal is the code. The signal supplied to the control unit and input to the level determination unit is a level attenuated by a predetermined amount from the level of the transmitted test signal,
When the DC power supply unit and the 2-wire / 4-wire conversion unit are out of order, test signals from the hybrid unit to the 2-wire / 4-wire conversion unit and the DC power supply unit are transmitted to the hybrid unit. Since the signal does not return, the signal corresponding to the difference between the transmission test signal of the pseudo echo path of the hybrid unit and the echo of the echo path is used as an echo return signal in the erasing circuit of the hybrid unit via the encoding unit. The level of the signal received by the level determination unit and input to the level determination unit is a level attenuated by a second predetermined amount from the transmitted test signal,
Since the signal does not pass if the codec unit fails, the echo return signal from the analog subscriber circuit for the test signal is not detected,
6. The test apparatus for an analog subscriber circuit according to claim 5, wherein a failure location corresponding to the level of the signal input to the level determination unit is specified. A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit Analog subscriber circuit testing equipment,
A signal transmitter for supplying a test signal to the analog subscriber circuit;
A signal detector for detecting a level of an output signal of the analog subscriber circuit with respect to the test signal with a set threshold;
A test controller ;
With
The test control unit switches the DC power supply unit to an on-hook transmission mode and switches to a loop back when the subscriber terminal is on-hook.
The test signal transmission unit transmits a test signal to the decoding unit of the analog subscriber circuit, and when the test signal is normal, the hybrid unit in the analog subscriber circuit, the 2-wire / 4-wire conversion Is returned by the encoding unit after being returned by the DC power supply unit via the unit,
A test apparatus for an analog subscriber circuit, wherein a failure location is determined by detecting a signal output from the encoding unit based on a predetermined threshold value in the signal detection unit. In the signal detection unit, when the signal is not detected with the first threshold, it is determined that the codec unit is faulty,
The threshold value of the signal level detected by the signal detection unit is set to a second threshold value, a test signal is sent to the analog subscriber circuit, and the DC power supply unit, the 2-wire / 4-wire conversion unit, and the hybrid unit are When a signal that has been turned back is detected, the test signal does not return to the hybrid unit due to a failure in the DC power supply unit or 2-wire / 4-wire conversion unit, so only the cancellation signal of the hybrid unit is returned. It becomes a level attenuated by a predetermined amount from the level of the transmitted test signal, and it is determined that the DC power supply unit, the 2-wire / 4-wire conversion unit is faulty,
If the signal detection unit could not detect the signal with the second threshold value, the test signal is normally folded by the DC power supply unit and the 2-wire / 4-wire conversion unit, 8. The analog subscriber circuit testing apparatus according to claim 7, wherein the analog subscriber circuit is determined to be normal. A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit To the computer that constitutes the test equipment for analog subscriber circuits,
When the subscriber terminal is on-hook, the DC power supply unit is set to an on-hook transmission mode and switched to a loop back, the signal transmission unit transmits a test signal to the decoding unit of the analog subscriber circuit, and the test signal is During normal operation, the hybrid unit in the analog subscriber circuit, the 2-wire / 4-wire conversion unit is returned by the DC power supply unit and returned from the encoding unit,
Determine the level of the signal output from the encoding unit,
A program for executing a process of determining whether the determined level is a normal level or a failure level . The signal returned to the hybrid unit via the DC power supply unit and the 2-wire / 4-line conversion unit is subtracted from the signal from the pseudo echo path in the hybrid circuit erasure circuit, and the subtracted signal is the code. The signal supplied to the control unit and subjected to level determination by the level determination unit is a level attenuated by a predetermined amount from the level of the transmitted test signal,
When the DC power supply unit and the 2-wire / 4-wire conversion unit are out of order, the test signal from the hybrid unit to the 2-wire / 4-wire conversion unit and the DC power supply unit 1 is the hybrid unit. Therefore, the level determination unit receives a signal corresponding to the difference between the transmission test signal of the pseudo echo path of the hybrid unit and the echo of the echo path as an echo return signal in the cancellation circuit of the hybrid unit. The signal determined by the level determination unit is a level attenuated by a second predetermined amount from the transmitted test signal,
Since the signal does not pass if the codec unit fails, the echo return signal from the analog subscriber circuit for the test signal is not detected,
The program according to claim 9, wherein the computer is caused to execute a process of specifying a failure location corresponding to the level by detecting the level of the echo return signal. A DC power supply for supplying direct communication current to a subscriber terminal; a 2-wire / 4-wire converter connected to the DC power supply for converting the two of the subscriber lines into four lines; and the 2-wire / 4-wire converter A hybrid unit that impedance-matches with the two-wire side so that the received signal does not wrap around the transmission signal on the four-line side, and a codec unit that is connected to the hybrid unit and has an encoding unit and a decoding unit To the computer that constitutes the test equipment for analog subscriber circuits,
When the subscriber terminal is on-hook, the DC power feeding unit is switched to an on-hook transmission mode and switched to a loop back,
A test signal is transmitted to the decoding unit of the analog subscriber circuit. When the test signal is normal, the DC power supply unit passes through the hybrid unit and the 2-wire / 4-wire conversion unit in the analog subscriber circuit. Is returned from the encoding unit,
The program which performs the process which judges a fault location by detecting the signal output from the said encoding part with a predetermined threshold value. In the signal detection unit, when the signal is not detected with the first threshold, it is determined that the codec unit is faulty,
The threshold value of the signal level detected by the signal detection unit is set to a second threshold value, a test signal is sent to the analog subscriber circuit, and the DC power supply unit, the 2-wire / 4-wire conversion unit, and the hybrid unit are When a return echo return signal is detected, the test signal does not return to the hybrid unit due to a failure of the DC power supply unit or the 2-wire / 4-wire conversion unit. Will be returned, it will be a level attenuated by a predetermined amount from the level of the transmitted test signal, it is determined that the DC power supply unit, the 2-wire / 4-wire conversion unit is faulty,
If the signal detection unit cannot detect the signal, the test signal is normally folded by the DC power supply unit and the 2-wire / 4-wire conversion unit, and the analog subscriber circuit The program according to claim 11, which causes the computer to execute a process of determining normality.

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