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Greg's DSL line statistics
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This page is of historical interest only. I stopped using DSL line when I left Wantadilla in July 2007.

In June 2005, after years of waiting, I finally got an ADSL connection to my home. Contrary to my fears, the line quality was more than ample. The Linksys AG241 gateway that I got has a web page showing the link status. Initially it showed an “Upstream Margin” of 23 dB and a “Downstream Margin” of 11 dB. They don't document what they mean by this term, but my guess is that it is the difference between the line attenuation and some arbitrary value at which they decide no signal is available; this would then be 73 dB downstream and 46 dB upstream. If anybody can clarify, I would be grateful.

The link worked flawlessly from the first time I plugged it in, though the technical and commercial problems with routing a network down it make interesting reading.

On 21 June, exactly two weeks after installation, that changed: the noise levels increased, the noise margins decreased accordingly, and the upstream speed dropped from an already low 256 kb/s to 160 kb/s. Coupled with the weather (heavy rain), all this looked like the scenario we have seen so many times in the past: telephone lines with damaged insulation get wet and fail. In the past, Telstra has been less than satisfactory in resolving this problem; in particular, they almost never uphold their Customer Service Guarantee, which requires faults to be repaired in two business days. The DSL gateway that I use provides line quality statistics, so this page helps document the current state. The graphs show:

Click on the graphs for a 1600x1200 version.

ADSL line statistics ADSL line statistics

The monitor scripts

The scripts that do this monitoring are:

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