JPH1032849A - Line trunk device and fault detecting method for private branch exchange - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a system which detects faults, even without the connection of a line system interface and also can easily specify a faulty part. SOLUTION: A highway controller 10 is connected to an incoming highway 22 and an outgoing highway 21 of a back wired board 20 and is provided with a loop pack circuit 14 which sends a signal sent from the highway 21 to the highway 22 at a delay timing that is equal to internal delay of a loop back path of a line system interface 30. For a fault detection test, a test pattern is checked by looping back a test pattern signal which is sent from a test pattern sending circuit 11 in the circuit 14 through the board 20, and then inputting the test pattern signal again in a detecting circuit 12 through the board 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a line trunk device of a private branch exchange which is mounted on a digital private branch exchange, accommodates a line interface, and exchanges data with a time division switch, and a method of detecting a failure thereof.

[0002]

2. Description of the Related Art A digital private branch exchange accommodates central office lines and subscriber lines via a line system interface, and performs exchange processing between the central office lines and the subscriber lines. That is, the private branch exchange has a line trunk unit (LTU) having a line system interface as a package and a highway controller accommodating these packages, and switching of signals input / output through the line system interface of the line trunk unit. Exchange unit (time-division switch: TS
W).

In such a configuration, in order to detect a failure in each section, a test pattern sending circuit is provided in the highway controller, and a determination device for performing a check based on the returned test pattern is provided. Is provided with a test signal folding circuit. In such a device, when a failure test is performed, a test pattern is transmitted from the highway controller, and a signal returned by the test pattern in the line interface is checked by a determination circuit, and the test is performed.

[0004]

However, in the above-mentioned conventional line trunk device of the private branch exchange, as described above, since a loopback circuit is provided inside the line system interface, the line system interface is mounted.
In addition, there has been a problem that failure detection of each unit can be performed only when the line interface is not operating. In addition, even when the failure test determines that a failure has occurred, there has been a problem that it is difficult to identify where the failure has occurred.

[0005] From such a point, it has been desired to realize a system that can detect a failure without connecting a line system interface and can easily specify a failure location.

[0006]

The present invention employs the following structure to solve the above-mentioned problems. <Structure of Claim 1> A line interface having a function of a subscriber interface and an office line interface and having a function of returning a signal, a highway controller accommodating the line interface, and a highway and a line interface of the highway controller In a line trunk device of a private branch exchange comprising a back-wired board for connecting to a signal path, a highway controller performs a failure detection based on a test pattern transmission circuit for transmitting a test pattern signal and a received test pattern signal. Connected to the detection circuit and the up and down highways of the back-wired board,
And a return circuit for transmitting a signal from the downstream highway to the upstream highway with a delay timing equal to the internal delay of the return of the line interface.

<Description of Claim 1> A line interface is a portion of a private branch exchange that has a function as, for example, an interface of a subscriber line or an office line of an analog line or a digital line. The highway controller is
This is a device that accommodates a line interface and exchanges data with a time-division switch, which is a higher-level device, via an upstream and downstream highway. In addition, back wired board,
This is a part for connecting a line interface to the highway of the highway controller.

When a failure detection test is performed, a test pattern signal transmitted from the highway controller is input to a back-wired board. Then, the test pattern signal is looped back by the loop circuit in the highway controller, returns to the back-wired board, and is further input to the detection circuit of the highway controller. The detection circuit is
By comparing the test patterns, it is determined whether a failure has occurred. Therefore, even if the line interface is not connected to the back-wired board, a failure detection test can be performed. Further, since the delay timing of the loopback circuit is configured to be equal to the delay timing of the loopback path of the line interface, transmission of the test pattern,
There is no need to separately provide a configuration for receiving a test pattern, and a conventional configuration for testing a line interface can be used as it is.

The line trunk device of the private branch exchange according to claim 1, further comprising a control unit for controlling transmission of a test pattern at a timing when a line interface is not used in serial data flowing on the highway. This is a line trunk device for a private branch exchange.

<Explanation of Claim 2> In the invention of claim 2,
According to the first aspect of the present invention, the transmission timing of the test pattern is defined, and the transmission timing is a timing at which the line interface is not used. Thus, even when the line interface is connected to the back-wired board and this line interface is operating, a failure detection test can be performed at all times.

According to a third aspect of the present invention, there is provided a method for detecting a failure in a line trunk device in which a highway controller accommodates a line interface having functions of a subscriber interface and a local line interface via a back wired board. A folding circuit for folding a signal through a back-wired board, and a failure detection test for folding a test pattern via the folding circuit and a failure detection test for folding via a folding circuit in a line interface. This is a fault detection method characterized by performing one test and then performing the other test.

<Explanation of Claim 3> In the invention of claim 3,
For example, first, a failure detection test is performed on a back-wired board that returns a test pattern via a return circuit, and then a failure detection test is performed via a return circuit of a line interface. Here, if no failure is detected in the failure detection test of the back-wired board and a failure is detected in the failure detection test of the line interface, it can be determined that the failure is on the line interface side. Conversely, a failure detection test in a line interface connection state may be performed first, and then a failure detection test of the back-wired board may be performed. In this case also, if a failure is detected in the failure detection test in the line interface connection state and no failure is detected in the failure detection test of the back-wired board, it can be determined that the failure is on the line interface side. it can.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. <Structure> FIG. 1 is a diagram showing a specific example of a line trunk device of a private branch exchange according to the present invention. The illustrated line trunk device includes a highway controller (HWC) 10, a back wired board (BWB) 20, and a line interface (LC) 30.

A highway controller (hereinafter, referred to as HWC) 10 accommodates a line interface 30 and transmits and receives data to and from a time-division switch (TSW) 100 as a higher-level device via a highway as a serial bus. It is. The HWC 10 includes a test pattern transmission circuit (PG) 11, a detection circuit (CHK) 12, and a switching circuit (S
EL) 13, a folding circuit 14, and a control unit 15. The test pattern sending circuit 11 sends an arbitrary test pattern signal for detecting a failure. The detection circuit 12 checks the folded test pattern signal,
This circuit detects whether a failure has occurred. The switching circuit 13 is a circuit that performs switching between a signal transmission process to a time-division switch (hereinafter, referred to as TSW) 100, which is an exchange process as an exchange, and a failure detection process.

The folding circuit 14 includes a down highway 21 of a back wired board (hereinafter referred to as BWB) 20.
, And the signal from the downstream highway 21 is adjusted to the same timing as the internal delay of the return path of the line interface 30 and transmitted to the receiver of the upstream highway 22. It is a delay circuit. The control unit 15 includes a processor, a memory, and the like. The control unit has a function of controlling the system interface 30.

The BWB 20 is a board for connecting the upstream and downstream highways of the HWC 10 to the line interface 30. The BWB 20 is connected to the HWC 10 via a connector. The receiving unit 22 is connected to the loopback circuit 14 in the HWC 10. Then, the control bus 23
It is connected to the control unit 15 of C10.

The line interface 30 comprises a plurality of line interfaces 30-1, 30-2,... And has a function of accommodating office lines and subscriber lines. In this specific example, two line-system interfaces 30 (30-1, 30-1
30-2) only. Line interface 3
0 is a highway interface (HWINF) 31,
A line interface 32 (INF), a highway loopback circuit (RTC) 33, and a controller (PP) are provided.

A highway interface (hereinafter, HWI)
NF) 31 is the downstream highway 2 of the BWB 20
1. Interface with the upstream highway 22. The line interface 32 is an interface for connecting an office line or a subscriber line. For example, the line interface 32 has a function of a codec for interfacing with an analog line, or a primary group rate of ISDN (Integrated Services Digital Network). Some have an interface function. The highway wrapping circuit 33 has a HWINF
This is a circuit for returning a signal from the downstream highway 21 to the upstream highway 22 via 31. Further, the controller (PP) 34
0 is a preprocessor for performing control of BWB2.
0 is connected to the control bus 23.

<Operation> First, in the normal exchange processing, the processing of each line system interface 30 is performed by serial data flowing on the upstream highway and the downstream highway. This processing is different from the characteristic point of this specific example. Since there is no direct relationship, the description is omitted here.

Next, the processing when a failure is detected will be described. When performing failure detection, the control unit 15
, A switching signal is transmitted at a predetermined timing, and the test pattern transmission circuit 11 transmits a test pattern.

FIG. 2 is an explanatory diagram of signals flowing through the highway. As shown in the figure, of the serial data flowing on the highway, each line interface 30 (LC1,
LC2,...) Are assigned time slots in advance.
Data exchange processing is being performed. In this specific example, a test pattern slot is prepared at a specific timing not used by the line interface 30, and the test pattern is transmitted / received through this slot.

When performing fault detection, the control unit 15 turns on the loopback circuit 14 and turns off the highway loopback circuit 33 of the line interface 30 so as to turn off the PP3.
Instruct 4 As a result, the test pattern becomes BWB2
0 on the highway 21 and BWB
The signal is input to the loopback circuit 14 of the HWC 10 from the transmission section of the downstream highway 21. In the folding circuit 14,
Normally, the test pattern is output to the receiving unit of the upstream highway 22 in the BWB 20 at the same timing as the line interface 30 is delayed by the internal processing. As a result, the test pattern is
And returns to the HWC 10 to be input to the detection circuit 12. The detection circuit 12 compares the test pattern transmitted from the test pattern transmission circuit 11 with the received test pattern. If the result of this comparison is correct, the down highway 21 and the up highway 22 of the BWB 20 are normal, and if there is an abnormality such that the test patterns do not match,
It is determined that a failure may occur in the BWB 20.

Such a failure detection operation does not affect the normal operation of the line interface 30, so that the test can be performed at all times while the line interface 30 is operating.

Further, by testing the BWB 20 and the line interface 30 separately, it is possible to specify a failure point. The control in this case is as follows. First, the control unit 15 instructs the test pattern sending circuit 11 to send a test pattern at the above-described timing. Then, an instruction is given to turn on the return circuit 14 and turn off the highway return circuit 33 of the line interface 30. Thus, a failure test of the BWB 20 is performed to detect whether or not a failure has occurred. Next, the return circuit 14 is turned off, the highway return circuit 33 is turned on, and the test pattern transmission circuit 11 transmits a test pattern. This test pattern is stored in the highway return circuit 33
, And compared by the detection circuit 12.

In such a test, a failure is not detected in the BWB 20, and if a failure is detected in the loopback test of the line interface 30, it can be determined that the failure is on the line interface 30 side. In such a test, a test between the BWB 20 and the line system interface 30 is performed by inserting only one test pattern in a frame of serial data and switching a return point. A test pattern for the interface 30 and a test pattern for the BWB 20 may be inserted, and the detection circuit 12 may detect each failure based on the timing of sending the test pattern.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a specific example of a line trunk device of a private branch exchange according to the present invention.

FIG. 2 is an explanatory diagram of signals flowing on a highway in the line trunk device of the private branch exchange according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Highway controller (HWC) 11 Test pattern sending circuit (PG) 12 Detection circuit (CHK) 13 Switching circuit (SEL) 14 Folding circuit 15 Control unit 20 Back wired board (BWB) 21 Down highway (BHW) 22 Up highway (FHW) ) 23 control bus (C bus) 30 line system interface 33 highway loopback circuit (RTC) 34 controller (PP)

Claims (3)

[Claims] 1. A line interface having a function of a subscriber interface and an office line interface and having a function of returning a signal, a highway controller accommodating the line interface, a highway of the highway controller, and the line interface. A line trunk device for a private branch exchange, comprising a back-wired board for connecting to a signal path of the private branch exchange, wherein the highway controller comprises: a test pattern transmitting circuit for transmitting a test pattern signal;
A detection circuit that detects a failure based on the received test pattern signal; and a detection circuit that is connected to an upstream highway and a downstream highway of the back wired board, and transmits a signal from the downstream highway with a delay timing equal to the internal delay of the loopback of the line interface. A line trunk device for a private branch exchange, comprising: a return circuit for sending the signal to a highway. 2. The line trunk device for a private branch exchange according to claim 1, further comprising a control unit for controlling transmission of a test pattern at a timing when a line interface is not used in serial data flowing on a highway. Private branch exchange line trunk equipment. 3. A failure detection method in a line trunk device in which a highway controller accommodates a line interface having a function of a subscriber interface and a local line interface via a back-wired board. A return circuit for returning a signal via a wired board is provided.A failure detection test for returning a test pattern via the return circuit and a failure detection test for returning via a return circuit in the line interface are provided. A failure detection method, comprising: performing a test and then performing the other test.