ADSL – StreamyX Noise Ratio/SNR Numbers & Line Attenuation – What Do They Mean?

It’s good to get to know your modem/router whichever ISP you are using, log in to the control panel and explore what kind of data it can give you.

You can most likely access your admin page here: or

If that doesn’t work, or you don’t know the login/password please RTFM or JFGI.

The basic thing to check when your line is activated is that you are getting the speed that you signed up for (512k/1mb/2mb etc.) and the DSL line is synced at that speed. Whichever modem/router are you using, it should show you that under the general status or ADSL status page.

Mine looks like this:

Streamyx 1MB Connection

It is supposed to be a 1mb so at least it’s synced at that speed. Ok that’s the basic part to make sure you have the right line speed, now DSL is running over some pretty old technology (copper lines) so the quality of your Internet connection depends on lots of bits of wire such as…

The wire from your phone socket out of your house, the wire from your house wall to the pole or underground. Or if you’re in a condo the wire from the distribution box into your condo/appt. If the wire is shit, so is your Streamyx connection.

Now this is the part most people are unaware of and I had to do a fair bit of Googling to make sense of the numbers so I’d share it here. In every modem I’ve tried so far, in one of the status screens you can also see the Noise Margin (Signal to Noise Ratio) and the Attenuation level, mine looks like this:

Streamyx Noise Ratio & Line Attenuation

Ok so what do these numbers means? Here’s a break down.

Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio)

Relative strength of the DSL signal to Noise ratio. 6dB is the lowest dB manufactures specify for modem to be able to sync. In some instances interleaving can help raise the noise margin to an acceptable level. The higher the number the better for this measurement.

  • 6dB or below is bad and will experience no sync or intermittent sync problems
  • 7dB-10dB is fair but does not leave much room for variances in conditions
  • 11dB-20dB is good with no sync problems
  • 20dB-28dB is excellent
  • 29dB or above is outstanding

Line Attenuation

Measure of how much the signal has degraded between the DSLAM and the modem. Maximum signal loss recommendation is usually about 60dB. The lower the dB the better for this measurement.

  • 20dB and below is outstanding
  • 20dB-30dB is excellent
  • 30dB-40dB is very good
  • 40dB-50dB is good
  • 50dB-60dB is poor and may experience connectivity issues
  • 60dB or above is bad and will experience connectivity issues

As you can see from the above numbers, as for Noise Margin – my upstream (22db) is better than my downstream (15db) but both are within an acceptable range and won’t cause any disconnection problems.

As for the line attenuation, that’s where it get’s ugly. My phone line is super quiet (on the few occasions I’ve used it for voice) and has some kinda hissing which gives me a probably got wet somewhere along the way and it sucks basically.

Both upstream (63db) and downstream (53db) are at dangerous levels..and may cause me connectivity issues. Which is right, when I fully load the line (download something at 1mb) it drops like shit and ping times can go up above 1000ms.

So to be realistic, what you should hope for on your Streamyx line is Noise Ratio of between 10-20db for both upstream and downstream and as for line attenuation, the lower the better but being in the 30-50db range would be fine. If you manage to get these numbers out of your router/modem do share them here,

I’m writing this, cos well soon I won’t be able to give any Streamyx tips because I’ll be on Unifi wuwu 😛




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22 Responses to ADSL – StreamyX Noise Ratio/SNR Numbers & Line Attenuation – What Do They Mean?

  1. Jason August 26, 2010 at 12:53 am #

    SNR 31 (down) 0 (up) No idea why 0 though.
    Attenuation 14 (down) 6 (up)

  2. 93T August 26, 2010 at 6:57 am #

    UNIFI FTW!! Finally, streaming prawn has never been better! W00TS! LOL..;D

  3. Mark August 26, 2010 at 10:11 am #

    Bugger, don’t rub it in hahaha 😛

    I can’t get Unifi in my new apartment 🙁 I hope they implement it soon

  4. KY August 26, 2010 at 10:43 am #


  5. Angie Tan August 26, 2010 at 11:43 am #

    Thanks for the explanation dude.. Now, time to tweak my line.. (evil)

  6. Tan Yee Hou August 26, 2010 at 12:51 pm #

    yay i applied on Monday. Guys are coming over on Wednesday to get it done for me so yay. Pr0n madness here we come.

    @ky – don’t you have unifi in ss3 yet?

  7. kimberlycun August 26, 2010 at 1:08 pm #

    err hi!

  8. Paul Tan August 29, 2010 at 12:42 am #

    SNR Margin
    38.0 22.0 db
    Line Attenuation
    6.5 5.0 db
    Data Rate
    4096 512 kbps
    Max Rate
    13280 1056 kbps

  9. ShaolinTiger August 30, 2010 at 11:59 am #

    Jason: Looks like you got a pretty stable line there.

    93T: No prawn la dude…Top Gear in HD hahaha.

    Mark: I’ll be rubbing it in when I get it up and running don’t worry LOL

    KY: 0_o

    Angie Tan: Hahah don’t break it wei!

    Tan Yee Hou: w00t finally real HSBB.

    Paul Tan: Wow, best figures I’ve seen so far – outstanding on both counts. You must get full speed all the time.

  10. moons September 3, 2010 at 11:17 pm #

    Hmm, here’s mine.

    Downstream Rate: 1024 kbps
    Upstream Rate: 512 kbps
    Downstream Margin: 24 db
    Upstream Margin: 18 db
    Downstream Line Attenuation: 47 db
    Upstream Line Attenuation: 12 db

    Heck, Unifi is only gonna be available in 2011 for my area. Boohoo. What a slow crappy roll out for Unifi.

  11. ShaolinTiger September 6, 2010 at 2:44 pm #

    moons: Looks like you got a pretty decent line there, mine is the worst of the lot so far LOL

  12. hisham September 16, 2010 at 7:18 pm #

    Downstream Upstream
    SNR Margin (dB): 30.3 4.0
    Attenuation (dB): 10.0 2.5
    Output Power (dBm):

  13. ShaolinTiger September 17, 2010 at 2:36 pm #

    hisham: Wow your upstream is even worse than mine.

  14. yensama September 19, 2010 at 12:04 am #

    Hi, I have some questions.

    I have been having trouble with my internet connection, which kept disconnect often.

    ISP checked and confirmed that they are sending proper service (ie. the promised speed). And that the problem is within the inhouse line, which I am ok with, if that is really the source of the problem. ’cause last week they managed to fix and got the speed to normal… for a few days. So I thought, if the line is the issue, maybe it shouldn’t have been possible to fix from the first place.

    Also, I live in a building with about 200 rooms but the others don’t seem to have the same problem.

    I just want to make sure before going through the big trouble of changing the line. If you have time to help, please.

    Btw, my connection is:
    Down Up
    SMR Margin 13.8 8.9
    Attenuation 31 41.7
    Rate 4708 415

    Oh, and the problem is the upstream speed. It is supposed to be 1000(1M). Now I can connect to internet but not sure when it is gonna go down again.

    Thanks in advance for any helps and comments.

  15. ShaolinTiger September 20, 2010 at 2:27 pm #

    yensama: Your line quality seems quite bad, especially your upstream. You might have intermittent problems with your connection, it could be the copper cable from your unit to the distribution box.

  16. chandru September 30, 2010 at 7:03 pm #

    morning 8:00 to evening 5:30 the connection did’t disconnect…after 5:30 connection frequently disconnects…what is the reason…?

  17. ShaolinTiger October 4, 2010 at 6:43 pm #

    chandru: Probably that your area is extremely congested. Peak (slowest) times for ADSL are 6pm-11pm.

  18. James November 27, 2010 at 1:59 pm #

    Hi, I have some questions.

    I have been having trouble with my internet connection, which kept disconnect often.ISP checked and confirmed that they are sending proper service. The streamyx technician has already cek my Noise Margin (AKA Signal to Noise Margin or Signal to Noise Ratio) and Line Attenuation…

    my snr margin right now is DB 6.5 downstream and 12.3 upstream
    my line Attenuation now is DB 39.0 downstream and 15.7 upstream

    the technian said that my line was ok because there are no noisy sound in my line…. I cek the snr margin is 6.5 that mean my line is not ok, it will often disconnected… What is the real reason… i have try so many way that ISP has tell me but same result…hmmm

  19. Zbig December 21, 2010 at 6:09 am #

    Operation Data
    Operation Data Upstream Downstream
    Noise Margin -16 dB 31 dB
    Attenuation 6 dB 11 dB
    Greets 🙂

  20. Eric January 5, 2011 at 1:45 pm #

    Here is mine
    SNR download = 36.3
    Upload = 26.0

    L.A download = 7.9
    upload = 6.3


  21. Richard January 23, 2011 at 2:26 pm #

    Fantastic post, I’ve always wondered what those numbers mean.

  22. mamamiyah February 13, 2012 at 7:28 pm #

    SNR – 23db/35db

    Attenuation – 14db/24db