JPH0126597B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control highway fault detection method in a digital concentrator of a time division switch.

Figure 1 shows the configuration of a digital line concentrator in a time division switch. A concentrating stage common section includes concentrating switches 31 and 32, a scanning memory 33, and a control memory 34, and has a function of controlling the concentrating stages, 4 is a distribution stage, and 5 is a processing device. The subscriber line interface unit 1 and the line concentrator common unit 3 each form one unit in terms of implementation, and include an upstream voice highway 201 and a downstream voice highway 203 for transmitting voice, and an upstream control highway 202 and a downstream voice highway for transmitting scanning information. A plurality of subscriber line interface units 1 are connected to a concentrator common unit 3 by a downlink control highway 204 that transmits control information.
It has come to be controlled by The above voice highways 201, 203 and control highway 2
02 and 204 have time slots equal to the number of subscriber circuits accommodated in the subscriber line interface section 1, and multiplex and transmit information of a large number of subscribers. Since this is the connection between the unit and the concentrator stage common section 3, a means for confirming normality is essential.

Here, the methods for detecting faults on up and down highways are: (1) Checking the pattern transmitted from the highway transmitter on the receiver side (for example, transmitting a specific pattern of data, or (2) connecting the up and down highways back and comparing the returned pattern with the sent pattern on one side. There is. However, when the former is applied to a line concentrator, either the transmitting side or the receiving side becomes the subscriber line interface section 1, and the number of these is provided according to the number of subscribers, and the hardware for fault detection is required. This method had the drawback of significantly increasing the amount of wear, and was not an appropriate method. In addition, in the latter method, in order to prevent an increase in the amount of hardware, the subscriber line interface section 1 is provided with only a return function, and the pattern sending and comparison functions are provided in the common section 3 of the concentrator stage or the distribution stage 4, etc. located above it. It was set up. In this case, the audio highways 201 and 203 are switched by the concentrator switches 31 and 32 to the distribution stage 4.
The voice highways of a plurality of concentrators can be tested by providing fault detection hardware in the distribution stage 4, but the control highways 202 and 204 are connected to the control memory of the concentrator stage common section 3. 34 to the subscriber line interface unit 1 and then closed in the section up to the scanning memory 33, there was a drawback that hardware for failure detection had to be provided for each line concentrator.

In order to eliminate the above-mentioned conventional drawbacks, the present invention includes means for transmitting audio data and control data in a mixed manner on the same highway, and means for detecting a failure in the audio data separated from the mixed signal,
When the voice data is normal, it is determined that there is no fault in the controlled highway, and the purpose is to provide a method for detecting faults in the controlled highways of a large number of line concentrators with less hardware. It is in. The drawings will be described in detail below.

FIG. 2 shows a first embodiment of the present invention.
In the figure, the same components as in FIG. 1 are denoted by the same reference numerals. That is, 1 is a subscriber line interface section;
3 is a line concentration stage common section, 4 is a distribution stage, 31 and 32 are upstream and downstream line concentration switches, 33 is a scanning memory, 3
4 is a control memory, the subscriber line interface unit 1 includes a multiplexing unit 11 and a demultiplexing unit 12, and the concentrator stage common unit 3 includes a serial-parallel converter 35 and a parallel-serial converter 36. . Two uplink highways 205 and 206 are connected between the subscriber line interface section 1 and the concentrator common section 3 via a multiplexing section 11 and a serial/parallel converting section 35, and the separating section 12 and Two down highways 207 and 208 are connected via a parallel-to-serial converter 36,
The audio data and control data are data obtained by combining half and half of one time slot in the multiplexer 11 and the parallel-serial converter 36, for example, the even-numbered and odd-numbered audio data and control data are combined every other bit. The data is sent as two data streams to the above two up and down highways, and the demultiplexer 12 and serial/parallel converter 35 decompose the data into audio data and control data and reconfigure them into the original data. It's summery. Further, the CDEC of the subscriber line interface section 1 has a loopback function, and the distribution stage 4 is provided with a known voice data fault detection means.

In the above line concentrator, when the distribution stage 4 sends a pattern of voice data for fault detection to the line concentrator stage common section 3, the pattern is transmitted to the downstream line concentrator switch 32.
is input to the parallel-to-serial converter 36, where it is mixed with downstream control data from the control memory 34 as described above. The mixed data is sent to the separation section 12 of the subscriber line interface section 1 through the down highways 207 and 208, and is once separated into the original voice data and control data. Thereafter, the audio data is looped back at CDEC and mixed with downlink control data at multiplexer 11. The mixed return data is for upbound highways 205 and 20.
6 to the serial/parallel converter 35, and only the audio data pattern for fault detection is sent back to the distribution stage 4 via the upstream concentrator switch 31.
The pattern of the returned voice data is checked by the failure detection means provided in the distribution stage 4, but the voice data is detected by all the hardware constituting the path, that is, each highway 20.
5 to 208, the multiplexing unit 11, the demultiplexing unit 12, the serial/parallel converter 35, the parallel/serial converter 36, and the concentrator switches 31 and 32 are not normal, so the data will not be correct. If it is not detected, it is confirmed that all of the above hardware is normal. By the way, in this hardware,
The part excluding the line concentration switches 31 and 32 also forms a path for control data, so if the voice data is normal, the control highway between the subscriber line interface section 1 and the line concentrator stage common section 3 remains unchanged. This also indicates that the path of control data including .

In this manner, according to the above embodiment, by detecting the failure only in the voice data without detecting the failure in the control data, it is possible to detect a failure in the data path including the voice highway and the control highway. Therefore, it is not necessary to provide a failure detection means for each line concentrator as in the conventional case, and a large number of failures in line concentrators can be detected with the addition of a small amount of hardware.

Note that the voice highway and control highway described in the above embodiment are the mixed highways 205 to 205.
208 in a time-sharing manner.

FIG. 3 shows a second embodiment of the present invention,
In this embodiment, data obtained by exclusive ORing the audio data and control data is sent separately from the control data, and on the receiving side, exclusive ORing with the control data is performed again to restore the original audio data. If the voice data is normal, it is determined that there is no failure in the path including the voice and control highways. That is, in FIG. 3, 13 and 14 are exclusive OR circuits provided in the subscriber line interface unit 1, and 37 and 38 are exclusive OR circuits provided in the concentrator stage common unit 3, respectively. The audio data output from 32 is exclusive-ORed with the downlink control data from the control memory 34 in the exclusive-OR circuit 38, and sent to the downlink mixed highway 210.
At step 4, the exclusive OR with the downlink control data sent to the downlink control highway 204 is performed again, and the data is decoded into the original audio data. Similarly, the uplink audio data is exclusive-ORed with the uplink control data and sent to the uplink mixed highway 209. It should be noted that the CDEC of the subscriber line interface unit 1 has a loopback function, and the distribution stage 4 is provided with voice data failure detection means.
The other configurations are the same as those of the first embodiment.

Therefore, according to the above embodiment, the signal pattern for fault detection of the audio data sent from the distribution stage 4 is determined by the exclusive OR of the hardware constituting the path, that is, each highway 202, 204, 209, and Since the data is returned to the distribution stage 4 as correct only if there are no faults in the circuits 13, 14, 37, 38 and the concentration switches 31, 32, the distribution stage 4 confirms that the audio data is normal. In this case, it means that there is no fault in the control highways 202 and 204, and by detecting a fault in the voice data path, a fault in the control highway can be detected at the same time, and there is no need to provide fault detection means for each line concentrator. It is only necessary to provide one exclusive OR circuit in each concentrator.

As explained above, according to the present invention, in a digital line concentrator of a time-division exchange in which a highway for transmitting voice data and control data is provided between a subscriber line interface section and a concentrator stage common section, voice data and control data can be transmitted. The system includes means for transmitting control data in a mixed manner on the same highway, and means for detecting a fault in audio data separated from the mixed signal, and determines that there is no fault on the controlled highway when the audio data is normal. Therefore, there is no need to provide control highway fault detection means in the common section of the line concentrator or subscriber line interface section, and voice data fault detection means can be provided in a higher distribution stage, etc. Since it is possible to detect a failure in the line concentrator, there is an advantage that an increase in hardware can be avoided and the reliability of the line concentrator can be improved.

[Brief explanation of drawings]

The drawings are for explaining the present invention. FIG. 1 is a block diagram showing a digital line concentrator for a time division switch, and FIG. 2 is a first embodiment of a digital line concentrator for a time division switch to which the method of the present invention is applied. FIG. 3 is a block diagram showing a second embodiment of the present invention. 1...Subscriber line interface section, 3...Concentration stage common section, 4...Distribution stage, 11...Multiplexing section, 1
2...Separation unit, 13, 14, 37, 38...Exclusive OR circuit, 31, 32...Uplink and downlink concentrator switch, 35...Serial-to-parallel conversion unit, 36...
Parallel-to-serial converter, 202, 204... Up and down control highway, 205, 206... Up highway, 207, 208... Down highway, 2
09,210...Mixed up and down highway.

Claims (1)

[Scope of Claims] 1. In a digital line concentrator of a time-division exchange in which a highway for transmitting voice data and control data is provided between a subscriber line interface section and a concentrator stage common section, voice data and control data are transmitted in the same manner. The present invention includes a means for transmitting mixed signals on a highway, and a means for detecting a fault in voice data separated from the mixed signal, and when the voice data is normal, it is determined that there is no fault on the controlled highway. A fault detection method for controlled highways featuring: 2. The control highway fault detection system as claimed in claim 1, characterized in that audio data and control data are bit-mixed in a time-division manner. 3. A failure detection method for a controlled highway according to claim 1, characterized in that the exclusive OR output of audio data and control data is transmitted on a highway other than the controlled highway.