JPH04137955A - Subscriber line maintenance system - Google Patents

Abstract

PURPOSE:To make communication between a subscriber line test equipment and an exchange at the maintenance of a subscriber line by sending a prescribed test signal to the subscriber line so as to detect the presence/absence of a prescribed test signal on the subscriber line and to control non-connection/ connection with the subscriber line. CONSTITUTION:When a network terminator 3 is tested while being disconnected from an ISDN subscriber line 6 at the maintenance test or the ISDN subscriber line test equipment 5 and a subscriber line terminator 2 are desired to be tested while being synchronized with each other, a switch 56 is closed to send a sinusoidal wave between the ISDN subscriber lines 6. When a test signal detection circuit 32 detects the sinusoidal wave, a switch 33 is opened through the signal line 34. Then a subscriber line transmission reception circuit 31 for network terminator is disconnected from the ISDN subscriber line 6, that is, the network terminator 3 is disconnected substantially from the ISDN subscriber line 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ISDN subscriber line maintenance system.

[Conventional technology]

Traditionally, when a maintenance person maintains or tests an analog subscriber line, a maintenance telephone called a Buttinsky is connected to the two-line subscriber line, and the voice signals, modem, etc. that pass through that line are monitored. The user listens to the transmission code to confirm that the line is active. Then, check that the line is not in use, and perform maintenance on that line.
Tests are being conducted.

Or call-by-call, which sends a digital signal to the subscriber's line, synchronizes, and starts communication.
In the case of an N-base rate subscriber line, whether or not communication is in progress can be confirmed by detecting the presence or absence of power of the digital signal on the subscriber line. Therefore, a digital signal power detector is used to confirm that communication is not in progress, and maintenance and testing of the subscriber line is performed.

[Problem to be solved by the invention]

To perform maintenance and testing on the SDN basic rate subscriber line mentioned above after confirming that it is not in use, a tester with the same interface as the network termination equipment is connected to the subscriber line. Even if we try to synchronize the subscriber line termination equipment of the exchange and this prototype to achieve two calls, transmit and receive various data, and test bit errors, it is not possible for the following reasons.

In conventional ISDN basic rate subscriber lines, two-wire full-duplex transmission is used between the subscriber line termination equipment and the network termination equipment, and a procedure for synchronization is determined. Even if a test device is connected to this subscriber line and a call procedure is started from the test device side, not only this test device but also the network termination device will react to the signal sent from the subscriber line termination device. Trying to synchronize. For this reason, two signals are sent in the direction of the subscriber line termination device on the subscriber line, one from the network termination device and the other from the test equipment, so the subscriber line termination equipment loses synchronization, and the test equipment and exchange Communication between them becomes impossible.

[Means to solve the problem]

The subscriber line maintenance system of the present invention is a maintenance system for an ISDN subscriber winding circuit connected to a network termination device.
a first detection means connected to the I5DN subscriber line via a first switch and detecting an ISDN digital signal; and a first detection means connected to the ISDN subscriber line via a second switch and configured to perform a predetermined test. an ISDN subscriber line tester comprising: a sending means for sending out a signal; and a first transmitting/receiving means for connecting to the ISDN subscriber line via a third switch and communicating with the ISDN exchange; Connecting to the subscriber line via a switch, the SDN
a second transmitting/receiving means for communicating with an exchange; and said ISDN.
and a second detection means for detecting the test signal sent from the subscriber line tester onto the ISDN subscriber line and controlling the fourth switch.

〔Example〕

Next, the present invention will be explained with reference to the drawings. FIG. 1 is a block diagram of one embodiment of the present invention.

The subscriber line termination device 2 of the I SDN exchange 1 is connected to the network termination device subscriber line transmitting/receiving circuit 31 . The test signal detection circuit 32 is connected to a network termination device 3 having a switch 33 for the 2-line, and the network termination device 3 is further connected to a terminal 4 via a 4-wire I5DN user/network interface line 7. There is. Also, I
The SDN subscriber line 6 includes a subscriber line transmitting/receiving circuit 51 for network termination equipment. Digital signal detection circuit 52. I having a test signal sending circuit 53 and two-wire switches 54 to 56
An SDN subscriber line testing device 5 is connected.

The test signal sent from the test signal sending circuit F185B is a low-frequency sine wave, the frequency of which is outside the band of the digital signal transmitted on the 15DN subscriber line 6, and
In order to reduce cable loss in the ISDN subscriber line 6, a frequency around 100 Hz is selected. However, the AC power supply frequency and its harmonics are excluded so that the test signal detection circuit 32 does not erroneously detect induction noise from the commercial AC power supply. Further, the test signal detection circuit 32 has a narrow band pass filter that passes only the frequency sent out from the test signal sending circuit 53, and has a function of detecting only that frequency.

Next, the operation will be explained.

The ISDN subscriber line testing device 5 with the switch 55 turned on and the switches 54 and 56 turned off is connected to the ISDN subscriber line 6. Here, if the digital signal detection circuit 52 does not detect a digital signal, the ISDN
It is assumed that the subscriber line 6 is not in communication, and maintenance/testing is started.

During maintenance tests, the network termination equipment 3 is connected to the ISDN subscriber line 6.
If you want to perform a test separate from the IS
If you want to perform a test with synchronization between the DN subscriber line tester 5 and the subscriber line termination device 2, turn on the switch 56 and send a sine wave between the lines of the 15DN subscriber line 6. do. When the test signal detection circuit 32 detects this sine wave, the switch 33 is turned off through the signal line 34. By doing so, the network termination device subscriber line transmission/reception circuit 31 is disconnected from the I5DN subscriber line 6, that is, the network termination device 3 is essentially disconnected from the I5DN subscriber line 6.

Furthermore, after this, if the switch 54 is turned on and the call procedure is started from the subscriber line transmitting/receiving circuit 51 for the network termination device, the communication between the I5DN subscriber line tester 5 and the subscriber line termination device 2 is You can synchronize with.

When these tests described above are completed, the switch 54 is turned off, and after confirming with the digital signal detection circuit 52 that the transmission of digital signals from the subscriber line termination device 2 has been stopped, the switch 56 is turned off. , IS
The transmission of the sine wave that was being transmitted onto the DN subscriber line 6 is stopped. The test signal detection circuit 32 detects that the transmission of the sine wave has stopped, and turns the switch 23 back on through the signal line 24. By doing so, the network termination device 3 is connected to the 15DN subscriber line 6 and returns to its initial state.

〔Effect of the invention〕

As explained above, the present invention provides that the subscriber line testing device has a test signal output path and sends a predetermined test signal to the subscriber line, and the network termination device has a test signal detection circuit. By detecting the presence/absence of a predetermined test signal on the subscriber line and controlling disconnection/connection with the subscriber line, communication between the subscriber line testing equipment and the exchange is achieved during subscriber line maintenance. This has the effect of making it possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention. 1...I SDN exchange, 2...Subscriber line termination device, 3...Network termination device, 4...Terminal, 5...I
SDN network operator line testing equipment, 6...15DN subscriber line, ISDN user/network interface line, 51.
...Subscriber line transmission/reception circuit for network termination equipment, ...Test signal detection circuit, 33,54.55 5 switch, 52...
・Digital signal detection circuit, ... test signal output path. 7... 6...

Claims (1)

[Claims] In a maintenance system for an ISDN subscriber winding circuit connected to a network termination device, a first detection means connects to the ISDN subscriber line via a first switch and detects an ISDN digital signal; ISDN
a sending means connected to the subscriber line and sending out a predetermined test signal; and a third switch connected to the ISD.
an ISDN subscriber line tester having a first transmitting/receiving means connected to the N subscriber line and communicating with the ISDN exchange;
a second transmitting/receiving means communicating with a DN exchange, and the ISD
and a second detection means for detecting the test signal sent from the N subscriber line tester onto the ISDN subscriber line and controlling the fourth switch. A subscriber line maintenance system.