This basically shows how much signal the HEAD END is getting compared to noise. The higher this number is, the better. As this number goes down, it means there is more and more noise in the line.
Usually this is caused by bad shielding, R59 cabling, or bad connectors/wall plates. It's not easy to determine the location of interference.
Upstream interference means that the head end is getting a lot of noise around the frequency that your cable modem broadcasts at (15 to 50Mhz). Troubleshoot this just like you would "fuzzy LOW channels".
Feedback received on this FAQ entry:
- This appears to have nothing to do with DSL, but instead it talks about cable modems, Coax cabling, and 15-50 Mhz.
DSL Upstream Signal (to Noise Ratio), in contrast, is low frequency -- 30-140 kHz, and sometimes a real mystery, since it can be unexpectedly high. Sometimes it can be false DSLAM readings, as with IKNS Remote line cards. Since Upstream frequencies are lower, upstream signal loss should be less and US SNR should be greater. But often it is not so at all.
A DSL-specific section to this (apparently) DSL-specific FA! would seem to be very helpful.
2009-05-05 16:14:07 (planiwa )