JPH03159350A - Isdn subscriber line test system - Google Patents

Abstract

PURPOSE:To start up the test of its own subscriber line by placing a telephone from a subscriber terminal to a digital audible tone sending device installed at an exchange. CONSTITUTION:A connection request is sent from a telephone set 5 to the exchange by dialing a telephone number allocated to the digital audible tone sending device(TNG) 13. A folded loop connecting a bit error measuring instrument(BEM) 14, a subscriber circuit(LC) 7, a subscriber line 1, a network terminating device(NT) 2, the subscriber line 1, the LC 7, and the BEM 14 is generated, and the BEM 14 calculates the bit error rate of a speech path loop by comparing a sent false random digital bit signal with a received signal. For example, when the result of a bit error rate exceeds 1/10<-6>, the BEM 14 starts up an audible tone sending start-up signal line 15 with frequency of 400Hz, and a maintenance engineer at a customer side can recognize the fact that the bit error rate is satisfactory by listening a tone of 400Hz. In such a way, it is possible to dispense with the start-up of the test from an exchange side.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an ISDN subscriber line testing method. [Prior Art] Conventionally, when testing subscriber lines, disconnection, ground fault,
In order to detect interference with power lines, etc., a test method has been put into practical use that selects the subscriber line under test from a line test stand on the exchange side and measures analog parameters such as insulation resistance, capacitance, and ground potential difference between the subscriber lines. It had been. [Problem to be solved by the invention] However, the conventional testing method described above has the following drawbacks. That is, the selection of the subscriber line to be tested is done from the exchange side, and the test cannot be started from the home equipment during construction of the home equipment, for example. In addition, the test items were tailored to conventional analog transmission systems, making it difficult to evaluate problems such as instantaneous interruptions in subscriber lines and deterioration of transmission quality due to noise, which are problems in digital transmission.

Particularly in recent years, there has been a need for new subscriber line testing methods for systems such as ISDN exchanges, which are based on the premise of digital transmission over existing subscriber lines, but testing has not been possible using conventional methods.

The purpose of the present invention is to activate the test of the subscriber's own line by making a call from the subscriber terminal to the digital audible tone transmitting device installed in the exchange, and to check the bit error rate using the loop pack method from the exchange side. An object of the present invention is to provide an ISDN subscriber line testing system that measures the measurement result and reports the measurement result as an audible sound to the test-activated subscriber in the premises.

[Means to solve the problem]

The ISDN subscriber line testing method of the present invention is applicable to at least two 6 4 kb / a subscriber terminal capable of using the S channel; a network termination device that loops back a specified channel to the exchange under control from the exchange; a subscriber control device that instructs the network termination device to loop back each channel; A call that uses one of the 64 kb/s channels as a communication channel can be automatically terminated.
A digital audible sound transmitting device that can be activated externally by inserting a digitized audible sound signal into the k b / s channel and, at a predetermined time, a digital signal transmitted to a measuring channel and a digital signal received from this measuring channel. a bit error measuring device that measures the bit error rate of this channel by comparing digital signals, and when testing the subscriber line, the one 64 kb/s channel is used as a communication channel from the subscriber. After a call arrives at the digital audible tone transmitting device,
The subscriber control device sends a loopback instruction for the 64 kb/s channel different from the channel used by the subscriber to the network termination device, and connects the loopback channel to the bit error measurement device. After measuring the bit error rate of the channel, the result of the measurement is transmitted to the subscriber by further inserting the digitized audio signal into the 64 kb/s channel between the subscriber and the subscriber. The method is characterized in that the digitized audible sound signal is at least one of a signal of a different frequency and a different intermittent signal for each result of the measurement. [Example] Next, the present invention will be explained with reference to the drawings. Figure 1 is a functional block diagram of one embodiment of the present invention. In Figure 1, subscriber line 1 is a network terminal equipment (hereinafter referred to as NT
) 2 and a subscriber circuit (hereinafter referred to as LC) 7.

Inside the house, the terminal adapter (hereinafter referred to as ADP) 3 connects to the house bus 4.
It is connected to N'T 2 at .

Conventional home equipment is connected to ADP 3, and in this embodiment two telephones 5.6 are connected since two 64 kb/s channels are available.

On the exchange side, subscriber line 1 is connected to subscriber control equipment (hereinafter referred to as L).
CC) terminated by LC7 controlled by 8. Here, since this subscriber has two 64 kb/s traffic channels, each channel is accommodated in a traffic path switch (hereinafter referred to as SW) 9, and the connection is made by a traffic path control device (hereinafter referred to as SWC) 10. controlled by

In addition, SW9 has a digital audible sound transmission device (hereinafter referred to as TNG).
13 and a bit error measuring device (below BEM〉14) are similarly accommodated.
This is done by activating the digital audible sound transmission device activation signal line group 15. The communication path path 16 is a 64 kb/s digital path connecting the l channel of LC7 and the TNG 13, and similarly, the communication path path {7 is the other one of the LC7
64 kb/s connecting channel and BEM14
It is a digital pass.

A central control unit (hereinafter referred to as CCE) 11 controls the SWC 10 and the LCC 8 via the system bus 2.

Next, the operation of this embodiment will be explained. When starting the subscriber line test, the telephone number assigned to the TNG 13 is dialed from the telephone 5, which is an in-home device, and a connection request is sent to the exchange.

Since this call is from a regular telephone, it uses one of the two 64 k b/s channels available to this subscriber (hereinafter referred to as the B1 channel).

The called TNG 13 responds to the incoming call request, and the call is automatically incoming. At this time, based on the normal call control procedure, CCE1
1 and SWC 1 0, the communication path 16 is closed.

Therefore, between the telephone 5 and TNG 13, ADP 3, home bus 4. The communication path through NT2, subscriber line 1, and LC7 is formalized. At this time, the CCE 11 recognized the calling telephone number and recognized that it was a subscriber line test activation request from the in-house equipment side.
After automatic call reception on TNG13, other 64 kb/s channels (hereinafter referred to as
Switch to close communication path bus 17 for (called B2 channel)
Instruct the CIO. At the same time, it issues a command to turn back the B2 channel to LCC8. The LCC8 then sends the B2 channel return command to NT.
2, and connects this B2 channel to communication path 17. The NT2 decodes this instruction, returns the downlink B2 channel sent from the exchange side as it is, and inserts it into the upstream B2 channel sent to the exchange side.

In this way, BEM14, LC7. subscriber line t, NT
2, Connect subscriber line 1, LC7, BEM14 6 4
This means that a loop of k b /s has been created.

Thereafter, BEM 14 begins transmitting a pseudo-random digital bit signal through channel path 17 toward the subscriber line for a predetermined period of time. The sent pseudo-random digital bit signal is folded back at NT2 and sent to BEM.
It is received at 14.

The BEM 14 compares the transmitted pseudo-random digital bit signal and the received signal bit by bit.
The bit error rate of the communication path loop that includes the subscriber line can be calculated.

Normally, the bit error rate of the LC7, SW9, and communication path bus 17, which are internal devices of the exchange, is considered to be zero, so the bit error rate of the communication path loop is substantially equal to the bit error rate of the subscriber line 1. ．． Next, the BEM 14 that has measured the bit error rate for a predetermined period of time activates the digital audible sound transmitter activation signal line group 15.

This digital audible sound transmission device activation signal line group 15 is composed of a plurality of signal lines, and when a specific signal line is activated, a specific digital audible sound signal corresponding to the signal line is inserted from the communication path 16 to the subscriber line side. .

For example, if the bit error rate result is 1/10-6 or more,
The BEM 14 activates a 400 Hz audible sound transmission activation signal line. As a result, the maintenance person inside the house hears the 400 Hz sound from the telephone 5 and knows that the bit error rate is good, and if the subscriber line is under construction, confirms that the construction has been carried out satisfactorily. Also, the bit error rate result is 1
/10-3 or less, the BEM 14 activates the 1000 Hz audible sound transmission activation signal line. As a result, the maintenance person inside the house can hear the 1000 Hz sound and know that the bit error rate is bad, and can know that the condition of the installed subscriber circuit R1 is bad.

In addition, in this example, the measurement result of the bit error rate is 400
Although we notified maintenance personnel using two types of audible tones: Hz and 1000Hz, it is generally possible to notify detailed measurement results using even more frequencies, and it is also possible to notify maintenance personnel using audible tones of two types, 1000 Hz and 1000 Hz. Audible sounds may also be used. [Effects of the Invention] As explained above, the present invention makes it possible to start testing of the own subscriber's line by making a call from the in-house equipment to the digital audible tone transmitting device installed in the exchange, and the The bit error rate, which is an important parameter for determining the quality of a digital transmission system, is measured using a loopback method, and the measurement results are immediately reported to the test initiator in the home as an audible sound. This has the effect of eliminating the need for test startup.

[Brief explanation of the drawing]

Figure 1 is a functional block diagram of one embodiment of the present invention. 1...Subscriber line, 2...Network terminal equipment (NT),
3...Terminal adapter (ADP), 4...Indoor bus,
5, 6... Telephone, 7... Subscriber circuit (LC), 8
... subscriber control device (LCCl9... call path switch (SW), 10... call path control device (SWC), 1
1... Central control unit (CCE), 12... System bus, 13... Digital audible sound transmission device (TNG),
14...Bit error measuring device (BEM), 15...
・Digital audible sound transmission device activation signal line group, 16.17・
...Call route bus.

Claims (1)

[Scope of Claims] 1. In an ISDN switching system in which a subscriber control device of an exchange and a network termination device face each other across a subscriber line, a subscriber who can use at least two 64 kb/s channels. a terminal, a network termination device that loops back a specified channel to the exchange under control from the exchange, a subscriber control device that instructs the network termination device to loop back each channel, and one of the 64 kb/s channels. A digital audible sound transmitter that can automatically receive a call to be used as a communication channel and that can be activated from the outside by inserting a digitized audible sound signal into the 64 kb/s channel; a bit error measuring device that measures the bit error rate of this channel by comparing a transmitted digital signal with a digital signal received from this measurement channel; /s
After a call using a channel as a speech channel arrives at the digital audible tone transmitting device, the subscriber control device sends a return instruction to the 64 kb/s channel, which is different from the channel used by the subscriber, to the network terminating device. after connecting the return channel to the bit error measuring device, measuring the bit error rate of the channel, and transmitting the digitized audible signal to the 64 kb/s channel between the subscriber and the subscriber. An ISDN subscriber line testing method characterized in that the result of the measurement is reported to the subscriber by inserting a . 2. I according to claim 1, wherein the digitized audible sound signal is at least one of a signal of a different frequency and a different intermittent signal for each result of the measurement.
SDN subscriber line test method.