Detecting a disconnect at a DSLAM
AssigneeBritish Telecommunications public limited company
InventorsLykourgos Kekempanos, Feiyu Fang
Life of this patent
Estimating the term…
Abstract
Detecting a short disconnection in a digital subscriber line, for example where the disconnection is near the DSLAM. A SELT UER trace is obtained from the digital subscriber line. The trace is analysed to determine its smoothness, as relatively smooth traces result from shorter lines. The smoothness measure can be calculated by applying some function to the differences of the amplitude between successive frequency tones. Two examples of functions that have been found to work well are a sum and a standard deviation. The result of the function can be compared to a threshold to determine if a short disconnection has occurred. Such a situation can occur when a cable has been disconnected from a patch panel for example.
Claims7
A method of detecting a short loop length termination fault in a digital subscriber line, said method comprising:
- generating a test echo response from the digital subscriber line using a single ended line test, wherein said test echo response comprises an amplitude at each of the plurality of successive frequency tones;
- calculating a result of a function applied to the differences of the amplitude between successive tones;
- performing a comparison of the result to a predetermined threshold;
- determining that there is short loop length termination fault in the digital subscriber line in dependence on an outcome of the comparison.
A test module for detecting a short loop length termination fault in a digital subscriber line, said test module adapted in operation to:
- generate a test echo response from the digital subscriber line using a single ended line test, wherein said test echo response comprises an amplitude at each of the plurality of successive frequency tones;
- calculate a result of a function applied to the differences of the amplitude between successive tones;
- perform a comparison of the result to a predetermined threshold;
- determine that there is short loop length termination fault in the digital subscriber line in dependence on an outcome of the comparison.
Dependencies are inferred from the claim text.