JPH02280447A - Subscriber line system test system - Google Patents

Abstract

PURPOSE:To measure the performance of a subscriber line system by providing a channel digital signal receiver to which a telephone number is assigned by an exchange, measuring the digital transmission characteristic of the subscriber line and informing the result of measurement to a telephone set in an audible tone. CONSTITUTION:The system is provided with a subscriber's terminal equipment 4 connecting to a network terminator 6, a telephone set 1 and a channel digital signal transmitter 2 connecting to the terminal equipment 4 and a channel digital signal receiver 10 to which a telephone number accommodated in an exchange is assigned. Then the telephone number of the channel digital signal receiver 10 is sent from the telephone set 1 at the subscriber line test and the digital signal sent from the digital signal transmitter 2 is received by the channel digital signal receiver 10 after the end of connection and the digital transmission characteristic of the subscriber line is measured and the result of measurement is informed from the channel digital signal receiver 10 to the telephone set 1 in an audible tone. Thus, the subscriber line system including the subscriber line 7, the network terminator 6 and a digital subscriber circuit 8 is tested.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a subscriber line system testing method for an I8DN exchange.

[Conventional technology]

Conventionally, this type of test involved selecting subscriber lines L7 from a test stand on the exchange side and measuring analog parameters such as insulation resistance, capacitance, and voltage to ground between the subscriber lines.

[Problem to be solved by the invention]

These tests were able to detect subscriber line cuts, ground faults, and power line cross-contacts. However, the above test method has the following drawbacks.

(1) The selection of the subscriber line is done from the exchange side, and for example, during construction of the home equipment, testing cannot be started from the home equipment side.

(2) The test items are tailored to conventional analog transmission systems, making it difficult to evaluate problems such as instantaneous interruptions in subscriber lines and noise intrusion, which are particularly problematic during digital transmission.

Therefore, there is a need for a new subscriber line system testing method, especially for systems such as 15DN exchanges, which are based on the premise of digital transmission on the subscriber J line.

[Means to solve the problem]

The subscriber line system test method of the present invention is applied to a subscriber line system in which a digital subscriber circuit of an exchange and a network terminating device face each other via a subscriber line under test. The subscriber line is equipped with a terminal device, a telephone terminal connected to the in-home terminal device, a channel digital signal transmitting device, and a channel digital signal receiving device housed in the exchange and assigned a telephone number. At the time of a test, the telephone number of the digital signal receiving device is sent from the telephone terminal, and after the connection is completed, the digital signal sent from the digital signal transmitting device is received by the digital signal receiving device and the telephone number of the digital signal receiving device is transmitted to the subscriber line. A subscriber line system including the subscriber line, the network termination device, and the digital subscriber circuit by measuring digital transmission characteristics and notifying the measurement result from the digital signal receiving device to the telephone terminal with an audible sound. This is the configuration for conducting tests.

〔Example〕

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

Referring to FIG. 1, which shows an embodiment of the present invention, on the exchange side, a digital subscriber circuit 8 and a channel digital signal receiver [10] can be connected to a channel via a switching network 9. This connection is made throughout the control path 12 under the command of the central controller 11. In addition, the control bus 12 is used not only for communication path connection commands, but also for transferring the telephone number of the receiving party from the digital subscriber circuit 8 to the central control unit 11, and for receiving communication path digital signals! ! It is also used to transfer incoming requests and responses to stack 0. The subscriber line 7 is part of the object to be measured in this example. The network termination device 6 faces the exchange through the subscriber line 7, and terminates the layer 1 or protects the home equipment from external surge signals and drives the home bus 5.

The home terminal device 4 is connected to the home bus 5, and provides an interface between the terminal device and the home bus 5. In this example, the home devices include a telephone 1 and a digital signal transmitting device 2.
3, this transmitter 2 is connected to the uplink (
The communication channel digital signal receiving device 10 is connected via the switching network 9 to the communication channel digital signal receiving device 10 . Further, on the downstream side of the communication path, a communication path digital signal receiving device 10 is connected via a switching network 9, and is connected to a telephone set 1 as an in-home device. The telephone 1 transmits the telephone number of the destination digital signal receiver 10 at the start of measurement, and listens to the audible sound sent from the digital signal receiver 10 after the measurement to indicate the quality of the measurement result. used for. The digital signal generated by the channel digital signal transmitter 2 is 2"-1 (n=1.2
--- It is a pseudo-random pattern with a predetermined initial value at a period of ). Communication path digital signal receiving device 1
0 allows detection of a pseudo-random pattern with the same period and the same initial value as the sending pattern. Therefore, it is possible to know how many pits of the digital signal sent out by the channel digital signal transmitting device #2 have arrived at the channel digital signal receiving device 10 in error, and to measure the bit error rate. be.

Next, let's talk about the operation. At the start of the test, first, the telephone number of the digital signal receiving device 1o is sent from the telephone 1 to make a call. This telephone number is placed on the signal channel of the subscriber line 7 and is input to the digital subscriber circuit 8 and then via the control bus 12 to the central control unit 11. When it is determined that the input telephone number information belongs to the digital signal receiving device IO, the central control device 11 sends an incoming call request to the device 10. When the device 10 returns an automatic response signal, a bus closure of the switching network 9 is instructed to connect the digital subscriber circuit 8 and the device 1o. All of these instruction/response signals are carried out through control bus 12. Through the above operations, the pseudo-random pattern digital signal from the transmitting device 2 is received by the receiving device 10 through the subscriber line 7. Since the period and initial value of the received digital signal are known in advance, it is possible to know how many bit errors have occurred during transmission. This gives an indication of the overall performance of the subscriber line system. Since most errors are considered to occur in the subscriber line 7, the digital transmission characteristics of the subscriber line 7 can be measured by measuring the error rate. Furthermore, the channel digital signal receiving device 10 is equipped with a lKHz sound source and a 400Hz sound source, and when the bit error rate is worse than a certain predetermined value (for example, 10),
The audible sound of z or, if possible, the audible sound of 400H2 is sent to the home device side. This audible tone is received by the telephone 1 on the home equipment side, and can notify the operator on the home equipment side of the bit error rate results.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to know the performance of a subscriber line system in which a digital subscriber circuit of an exchange and a network termination device face each other across a subscriber line.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention. l...Telephone, 2...Call path digital signal transmitter, 4...Home terminal device, 5...
...Internal bus, 6...Network termination device, 7...
...Subscriber line, 8...Digital subscriber circuit,
9゛°・°゛exchange network, lO: communication path digital signal receiving device, 11: central control unit, 12: control bus. Agent Patent Attorney Susumu Uchihara

Claims (1)

[Claims] In a subscriber line system in which a digital subscriber circuit of an exchange and a network terminating device face each other via a subscriber line to be measured, a home terminal device connected to the network terminating device and a home terminal device connected to this home terminal device. A telephone terminal and a communication path digital signal transmitting device are provided, and a communication path digital signal receiving device is housed in an exchange and a telephone number is assigned. The telephone number of the receiving device is sent, and after the connection is completed, the digital signal sent from the digital signal transmitting device is received by the digital signal receiving device, the digital transmission characteristics of the subscriber line are measured, and the measurement results are transmitted to the digital signal receiving device. A subscriber line characterized in that a subscriber line system including the subscriber line, the network termination device, and the digital subscriber circuit is tested by notifying the telephone terminal with an audible tone from a signal receiving device. System test method.