JPH0750909B2 - ISDN subscriber line test method - Google Patents

Description

The present invention relates to an ISDN subscriber line test system.

[Conventional technology]

Conventionally, for testing the subscriber line, disconnection, ground fault,
Practical application of a test method that selects the subscriber line under test from the circuit test stand on the exchange side to measure contact with the power line and measures analog parameters such as insulation resistance, capacitance, and ground potential difference between the subscriber lines It had been.

[Problems to be Solved by the Invention]

However, the above-mentioned conventional test method has the following drawbacks. That is, the subscriber line to be tested is selected from the exchange side, and the test cannot be started from the home equipment during the construction of the home equipment, for example. Further, the test items are those adapted to the conventional analog type transmission system, and it is difficult to evaluate the instantaneous interruption of the subscriber line and the deterioration of the transmission quality due to the mixing of noise, which are particularly problematic during digital transmission.

In particular, recently, a new subscriber line test method has been required for a system that assumes digital transmission through an existing subscriber line such as an ISDN exchange, but it cannot be tested by the conventional method.

An object of the present invention is to activate a test of one's own subscriber line by calling a digital audible sound transmitting device installed in a switch from a subscriber terminal, and to perform a bit error rate by a loopback method from the switch side. The purpose of the present invention is to provide an ISDN subscriber line test method that measures the measurement result and reports the measurement result as an audible sound to the test activation subscriber at home.

[Means for Solving the Problems]

The ISDN subscriber line test method of the present invention can use at least two 64 kb / s channels in the ISDN exchange system in which the subscriber control device of the exchange and the network terminating device face each other across the subscriber line. A subscriber terminal and a network terminating device that folds back a channel designated by the control from the exchange to the exchange, and a subscriber control device that instructs the network terminating device to fold back for each channel; A call using one of the 64 kb / s channels as a call channel can be automatically received, and a digital audible sound transmission device that can be activated from the outside by inserting a digitized audible sound signal into the call channel, and is predetermined. Bit error of this measurement channel by comparing the digital signal transmitted to the measurement channel with the digital signal received from this measurement channel for A bit error measuring device for measuring a rate is provided on the exchange side, and the digital audible sound transmitting device is used for a call using one of the 64 kb / s channels from the subscriber terminal as the communication channel when testing the subscriber line. After receiving the call, the subscriber control device sends a return instruction to the network terminating device to use the 64 kb / s channel other than the communication channel used by the subscriber terminal as a return channel, and the return channel. After connecting to the bit error measuring device, the bit error rate of the return channel is measured, and the digitized audible signal is inserted into the communication channel between the subscriber terminal and the digital audible sound transmitting device. By doing so, the result of the measurement is notified to the subscriber terminal.

〔Example〕

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a functional block diagram of an embodiment of the present invention.

In FIG. 1, the subscriber line 1 is a network terminating device (hereinafter NT).
It is placed between 2 and the subscriber circuit (hereinafter LC) 7.

Inside the house, the terminal adapter (ADP) 3 is N on the house bus
It is connected to T2.

A conventional home device is connected to the ADP3, but since two 64 kb / s channels are available in this embodiment, two telephones are used.
5 and 6 are connected.

On the exchange side, the subscriber line 1 is a subscriber control unit (hereinafter LC
C) Terminated by LC7 controlled by 8. Since this subscriber has two 64 kb / s channel channels, each channel is accommodated in a channel switch (hereinafter SW) 9 and its connection is controlled by a channel controller (hereinafter SWC) 10. It

The SW9 also houses a digital audible sound transmitting device (hereinafter TNG) 13 and a bit error measuring device (hereinafter BEM) 14 in the same manner. The activation of the TNG 13 is performed by the BEM 14 activating the digital audible sound transmitting device activation signal line group 15.

The communication path 16 is 64 kb / s connecting one channel of LC7 and TNG13.
Similarly, the communication path 17 is a 64 kb / s digital path that connects the other channel of the LC 7 and the BEM 14.

Central control unit (hereinafter CCE) 11 is S via system bus 12.
Controls WC10 and LCC8.

Next, the operation of this embodiment will be described.

When activating the subscriber line test, the telephone number assigned to the TNG 13 is dialed from the telephone 5 which is a home device and a connection request is sent to the exchange.

Since this call is a normal telephone call, one of the two 64 kb / s channels available to this subscriber (hereinafter referred to as the B1 channel) is used.

The called TNG 13 responds to the incoming call request, and this call is automatically received. At this time, CCE11 and SWC10 based on normal call control means.
The call path 16 is closed.

Therefore, between the telephone 5 and TNG13, ADP3, home bus 4, NT2,
A call path is formed through the subscriber line 1 and LC7.

At this time, CCE11, which recognizes that it is a subscriber line test activation request from the home equipment side by the calling telephone number, TNG13
After the automatic call is received, the SWC 10 is instructed to close the communication path 17 for another 64 kb / s channel (hereinafter, referred to as B2 channel) which is not in use on the same subscriber line. At the same time, the loopback instruction of B2 channel is issued to LCC8.

The LCC 8 thereby sends a loopback command for the B2 channel to the NT2, and connects this B2 channel to the communication path 17.

NT2 decodes this instruction, returns the downlink B2 channel sent from the exchange side as it is, and inserts it into the uplink B2 channel sent to the exchange side.

In this way, BEM14, LC7, subscriber line 1, NT2, subscriber line 1,
A 64 kb / s folded loop connecting LC7 and BEM14 was created.

After this, the BEM 14 starts transmitting a pseudo random digital bit signal toward the subscriber line side through the communication path 17 for a predetermined time. The sent pseudo random digital bit signal is folded back by NT2 and received by BEM14.

The BEM 14 can calculate the bit error rate of the speech path loop including the subscriber line by comparing the transmitted pseudo random digital bit signal with the received signal bit by bit.

Normally, the bit error rate of the switch internal devices LC7, SW9, and the communication path 17 is considered to be zero, so the bit error rate of the above communication path loop is substantially equal to the bit error rate of the subscriber line 1. .

Next, the BEM 14 measuring the bit error rate for a predetermined time activates the digital audible sound transmitting device activation signal line group 15.

The digital audible sound transmitter 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 signal corresponding thereto 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, BEM14
Activates the 400Hz audible sound transmission activation signal line. As a result, the maintenance person inside the home knows that the bit error rate is good by hearing the sound of 400 Hz from the telephone 5, and confirms that the work was carried out well if the subscriber line was under construction. If the bit error rate result is 1/10 ^-3 or less,
BEM14 activates the 1000Hz audible sound transmission activation signal line. As a result, the maintenance person inside the home can hear the sound of 1000 Hz and know that the bit error rate is bad, and that the condition of the installed subscriber line 1 is bad.

In this embodiment, the measurement result of the bit error rate is 400 Hz,
Notifying the maintenance person with two kinds of audible sound of 1000Hz, but in general, it is also possible to notify detailed measurement results by using multiple frequencies, and intermittent audible sound with different interruption ratios at the same frequency. May be used.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described above, the present invention makes it possible to activate the test of the subscriber's own line by calling the digital audible sound transmitting device installed in the exchange from the home equipment, and by the loopback method from the exchange side. Since the bit error rate, which is an important parameter for the quality of the digital transmission system, is measured and the measurement result is immediately reported to the test starter in the house as an audible sound, the test start from the exchange side is unnecessary. Has the effect of becoming.

[Brief description of drawings]

FIG. 1 is a functional block diagram of an embodiment of the present invention. 1 ... subscriber line, 2 ... network terminating device (NT), 3 ... terminal adapter (ADP), 4 ... home bus, 5, 6 ... telephone,
7 ... Subscriber circuit (LC), 8 ... Subscriber control device (LC
C), 9 ... Speech path switch (SW), 10 ... Speech path control unit (SWC), 11 ... Central control unit (CCE), 12 ... System bus, 13 ... Digital audible sound transmission device (TNG) ),14
…… Bit error measuring device (BEM), 15 …… Digital audible sound transmitting device activation signal line group, 16, 17 …… Channel path.

Claims (2)

[Claims] 1. An ISDN switching system in which a subscriber control device of a switch and a network terminating device face each other across a subscriber line, and at least two subscriber terminals capable of using 64 kb / s channels, A network terminating device that folds back a channel designated by the control of the exchange to the exchange is provided inside the home, and a subscriber control device that instructs the network terminating device to fold back each channel, and one of the 64 kb / s A call that uses a channel as a call channel can be automatically received, and a digital audible sound transmission device that can be activated from the outside by inserting a digitized audible sound signal into the call channel, and a measurement channel for a predetermined time. A bit error measurement that measures the bit error rate of this measurement channel by comparing the transmitted digital signal with the digital signal received from this measurement channel. -A measuring device is provided on the exchange side, and at the time of testing the subscriber line, after the call to the one of the subscriber terminals using the 64 kb / s channel as the communication channel is received by the digital audible sound transmitting device, The subscriber control device sends a loopback instruction to the network terminating device to use the 64 kb / s channel other than the speech channel used by the subscriber terminal as a loopback channel, and the loopback channel is measured for the bit error. Measuring the bit error rate of the folding channel after connecting to the device and inserting the digitized audio signal into the speech channel between the subscriber terminal and the digital audio output device. The ISDN subscriber line test method characterized in that the result of the above is reported to the subscriber terminal. 2. The ISDN according to claim 1, wherein the digitized audible sound signal is either a signal having a different frequency or a different intermittent signal depending on the result of the measurement.
Subscriber line test method.