ADSL signal to noise ratio and line attenuation chart

Whilst trying to diagnose my broadband connection problems I found many articles telling me to look at my modems values for signal to noise ratio and line attenuation values. The articles would then give big and complicated descriptions talking about distance to exchanges, DSLAMS, frequencies and all kinds of other things which I’d classify as ‘too much information’.

What I wanted was a simple chart so I could see if the signal to noise ratio and line attenuation values that my modem was reporting were good or bad. As I couldn’t find such a chart anywhere I made one.

To use it look up the values on your modem and see where they are on the chart. Needless to say green is good and red is bad.

adsl signal noise ratio and line attenuation chart

If you do want to read more about these values then this ADSL Wikipedia article is a good place to start, and has a useful list of definitions.

3 Comments on “ADSL signal to noise ratio and line attenuation chart”

  1. Hi
    A good idea but unfortunately its not quite correct . Most Routers/modems report SNR margin NOT SNR . where as you show High SNR is good High SNR margin is NOT the default for ADSL is 6db.
    Regards Jeff

  2. Hi
    SNR margin is the difference between ACTUAL SNR and minimum SNR needed for modem to work.

    ie if amodem show 8 db SNR margin, actual SNR (8db +minimum snr required for that modem {say 6db} ) may be 14 db

  3. interesting :)
    my average snr is 29db which is good
    but then line attenuation is 51, not good

    oh and my SNR margin is 9db – but thats another thing

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