JP2921069B2 - Test method for interoffice line - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a test system for a digital electronic exchange and an interoffice line between the digital electronic exchanges.

[Conventional technology]

Conventionally, CEPT (European Poast and Telecommunication
Conference) When performing a line test between the local station and the opposite station on a PCM (Pulse Code Modulation) primary group digital circuit, the local operator sets the time slot number from the test stand, On the station side, the maintenance personnel set the time slot number to be looped back and performed the test.

[Problems to be solved by the invention]

In the above-described conventional inter-station line test method, a maintenance person designates a time slot number to be tested from a test stand, determines a line state from a transmitted test signal and a folded test signal, and detects a line failure. Because we are doing
There was a problem that the line test could not be performed automatically.

[Means for solving the problem]

The test method of the interoffice line according to the present invention includes a central processing unit that performs exchange processing of an exchange, a time division switch that performs time division connection processing under the control of the central processing unit, and a line control command from the central processing unit. Therefore, an inter-office line for testing the digital line between a digital electronic exchange and a digital electronic exchange including a line control device for controlling the digital line via a digital trunk for terminating the digital line of the CEPT system PCM primary group In the test method of the above, the digital trunk controlled by the line control device is configured such that, at the time of the test of the digital line, the time slot under test is inserted into a time slot prescribed for domestic use in the digital line and the digital trunk is inserted. The line test control unit to be sent to the line and the received digital line data An extraction / insertion circuit for extracting the time slot corresponding to the time slot number under test indicated by the time slot indicated and inserting the time slot number into the time slot under test on the transmitting side; A fault detecting circuit for detecting a fault in the digital line by comparing test time slot data is provided.

[Action]

In the present invention, the line test is automatically performed when the inter-station line of the CEPT PCM primary group digital line is tested.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 FIG. 1 is a block diagram showing one embodiment of the present invention.

The test method of this interoffice line is to test the CEPT PCM primary group digital lines 20 and 21, and to test the digital lines 20 and 21.
The local exchange system 10 is connected to one end of the local exchange system, and the remote exchange system 30 is connected to the other end.

In addition, the local exchange system 10 provides a central processing unit 11 which issues a digital exchange processing instruction and performs exchange processing of the exchange.
And a time-division switch 12 for receiving a control instruction from the central processing unit 11 and performing time-division connection processing under the control of the central processing unit 11, and a CEPT PCM primary group in accordance with a line control instruction from the central processing unit 11. A digital line trunk that is connected between the line control unit 13 that controls the digital line and the digital lines 20 and 21 and the line control device 13 via a digital trunk that terminates the digital line of the digital trunk 14. When testing the digital line, insert the time slot number under test into the time slot specified for domestic use in the digital line, and
A line test controller 14A for transmitting to 20 and a time slot corresponding to the time slot number to be tested indicated by the time slot specified for domestic use in the received digital line data are extracted and transmitted to the transmission side time slot to be tested. An extraction / insertion circuit 14B to be inserted and a failure detection circuit 14C for detecting a failure in the digital line by comparing the transmitted time slot data under test with the returned time slot data under test are accommodated.

Similarly, the opposing exchange system 30 also issues a command for digital exchange processing and performs a central processing unit 31 for exchanging exchanges.
A time-division switch 32 for receiving a control instruction from the central processing unit 31 and performing a time-division connection process under the control of the central processing unit 31, and a line control instruction from the central processing unit 31 A line controller 33 for controlling a digital line via a digital trunk for terminating a group of digital lines, and digital lines 20, 21 and a line controller 33
And a digital trunk 34 connected between the digital trunks.
A line test control unit 34A that inserts a time slot number under test into a time slot specified for domestic use on a digital line and sends the same to the digital line, and a time slot specified for domestic use in received digital line data. An extraction / insertion circuit 34B for extracting the time slot corresponding to the time slot number to be tested indicated by the symbol and inserting it into the time slot to be tested on the transmitting side, and the transmitted time slot data to be tested and the folded time slot data to be tested. A failure detection circuit 34C for detecting a failure of the digital line by comparison is accommodated.

In the test method of the inter-station line configured as described above,
The line test control unit 14A provided in the digital trunk 14 of the local exchange system 10 is for transmitting a signal to the digital line 20, and specifies a time slot number to be tested. Then, the CCITT (International Telegraph and Telephone Advisory Committee) recommendation (G.704) for CEPT PCM primary group digital circuits 20 and 21
In the above, among the 32 time slots, five bits 4 to 8 in time slot 0 not including the frame synchronization signal are defined for domestic use. Then, the time slot number to be tested is designated using the five bits specified for the domestic use. The line test controller 14A designates the time slot number under test and inserts a signal into the time slot number 0.

The extraction / insertion circuit 34B provided in the digital trunk 34 of the remote station switching system 30 receives the transmitted signal, extracts the specified time slot signal under test, and extracts it to the corresponding time slot on the transmission side. The inserted time slot signal is inserted. As a result, the signal of the designated time slot transmitted from the own station is immediately looped back by the opposite station. The fault detection circuit 14C provided in the digital trunk 14 of the local exchange system 10 stores the signal of the time slot under test transmitted by the local station, and
And the signal of the time slot under test returned from the digital trunk 34 on the opposite station side. The state of the line is determined based on the comparison result, and a failure is detected.

Next, the operation of the embodiment shown in FIG.
A description will be given with reference to FIG. 2 which is a frame configuration diagram of a CEPT PCM primary group digital line recommended by the ITT.

In FIG. 2, FA indicates a frame including a frame synchronization signal, and FB indicates a frame not including a frame synchronization signal. In addition, Si indicates a spare bit, A indicates an alarm bit, and Sn indicates a domestic bit.

First, in a CEPT PCM primary group digital line recommended by CCITT, one time slot consists of 8 bits, and one frame consists of 32 time slots. Here, of the 32 time slots, the time slot 0 of the frame FA including the frame synchronization signal has a specific bit pattern and is used for frame synchronization. The time slot 0 of the frame FB that does not include the frame synchronization signal has a configuration of 1 bit for spare, 1 bit for alarm, and 5 bits for domestic use.

The time slot number under test is specified by these 5 bits,
The line test control unit 14A of the own station inserts the data into the time slot 0 and sends it out to the digital line 20. Local station fault detection circuit
14C fetches and stores the data of the specified time slot to be tested. The opposite station side extraction / insertion circuit 34B
Upon receipt of the specified time slot number to be tested in time slot 0, the reception data of the corresponding time slot is extracted from the line. Then, the extracted data is inserted into the corresponding time slot of the transmission line. The own-station-side fault detection circuit 14C receives the time-slot data under test returned by the opposite-station-side extraction / insertion circuit 34B and compares it with the pre-stored time-slot data under test. If the result of the comparison indicates that the data does not match, it is determined that the line is faulty and a report to that effect is made.

Normally, all 5 bits for domestic use are fixed at "1", but only when the local station side line test control section 14A sends other signals, the opposite station side extraction / insertion circuit 34B applies the corresponding time slot. Extract and insert. Time slot 0 and time slot 16 are frame synchronization signals and line control signals, and are not used for line testing.

〔The invention's effect〕

As described above, the present invention automatically reduces the burden of maintenance personnel during line tests by automatically testing the inter-station lines for each time slot when testing the CEPT PCM primary group digital line inter-station lines. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG.
FIG. 3 is a frame configuration diagram of a CEPT PCM primary group digital line recommended by CCITT. 10 local switching system, 11 central processing unit, 12
… Time-division switch, 13… Line controller, 14… Digital trunk, 14A… Line test controller, 14B…
Insertion circuit, 14C Fault detection circuit, 20, 21 Digital line, 30 Switching system on the opposite station, 31 Central processing unit, 32 Time-division switch, 33 Circuit control unit, 34
… Digital trunk, 34A …… Line test controller, 34B…
... Extraction / insertion circuit, 34C ... Fault detection circuit.

Claims (1)

(57) [Claims] A central processing unit for performing exchange processing of an exchange;
The digital line via a time-division switch for performing time-division connection processing under the control of the central processing unit and a digital trunk for terminating the digital line of the primary group of the CEPT system PCM according to a line control command from the central processing unit. In a test system of an interoffice line for testing the digital line between a digital electronic switch having a line control device for controlling the digital line and the digital electronic switch, the digital trunk controlled by the line control device is provided for the digital line. At the time of the test, a line test control unit for inserting a time slot number under test into a time slot specified for domestic use in the digital line and transmitting the same to the digital line, and receiving line data specified for domestic use in received digital line data. Corresponding to the time slot number under test indicated by the current time slot An extraction / insertion circuit for extracting the time slot to be inserted into the time slot to be tested and comparing the transmitted time slot data with the returned time slot data to detect the fault of the digital line. A test method for an inter-station line, comprising a fault detection circuit.