How to: Check your ADSL line's maximum supported speed -

edited October 2014 in Help! I gone and broke it
imageHow to: Check your ADSL line's maximum supported speed -

Have you ever wondered what your ADSL line is capable of? Well, wonder no more with the use of this handy guide.

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  • Great article, help to better understand the issues im having with my line!
  • Thanks for a very useful article.

    My line stats are below. As you can see I get 3072 on a 4Mbps line. Telkom says my line (0217948578) can manage 10Mbps. I was unclear though what is high or low attenuation?

    ADSL Link Downstream Upstream
    Connection Speed 3072 kbps 512 kbps
    Line Attenuation 26.5 db 14.0 db
    Noise Margin 19.6 db 12.0 db
  • @connecteddale Good question - the general rule of thumb is that less than 16dB is ideal and should give you close to max line speed, under 20dB is very good and under 30dB should be acceptable. So looking at your results there, your attenuation is 26.5dB to 14dB, which is pretty good. You're probably looking at 8Mbps on a 10Mbps line as a guess.
  • Hi sir can you check out my line stats

    Information DownStream Upstream
    SNR Margin 22.4 db 8.4 db
    Attenuation 26.0 db 13.7 db
    Data Rate 6140 kbps 1019 kbps
    Forward Error Correction Seconds 67 0
    CRC Errors 0 0
    Output Power 0.0 dbm 12.3 dbm

    I am currently on a 3mbps account... is it safe to upgrade to 5mbps or 8mbps?
  • Hi Bryan,

    That's odd - the stats you've posted there suggest you're already getting 6Mbps download speed (data rate = 6140kbps = 6.1Mbps). Either they're wrong, or your ISP has set something up incorrectly on their side.

    I'd run a test on your connection to see what your real download speed is. If it's still over 5Mbps and you're being charged for 3Mbps, you could do the right thing or just keep quiet...

  • HennieHennie Randburg, Jhb
    Hi I used to have Telkom ADSL a few years ago but ended my contract with Telkom completely because the condition of the lines were so bad, you could hear crackling noises on the phone! Needless to say I paid for an ADSL line that hardly ever connected. I still have Telkom copper lines to my house. Since I don't have a modem, is it possible for a Telkom technician to come to my house and physically test the line's attenuation and calculate my TRUE ADSL speed that I would have?
  • I'm not sure Telkom will commit to true ADSL speed, on account of the fact that it would constitute some sort of guarantee of delivery (hence the classic 'up to'... when advertising ADSL speeds). It might be worth getting the lines tested though - things might have changed and they should certainly be able to give you a rough idea of the quality.
  • As it stands my area's exchange cannot handle more than 4mbps, so how do i find out if Telkom will be looking into this without having to hold on to the phone waiting on teh Telkom operator? Any email address i can use?
  • Hi, this is what it says about my area ....Maximum speed available in your area 40Mbps (Copper) Your Current Service speed10 Mbps ......yet I have never got more than 3.8mb, usually less than 3.5. Should I be complaining? We are paying for Telkom Fastest
  • @Tracy London 10Mbps is the fastest you can get on standard ADSL. To get 20 or 40Mbps you'll need to upgrade to VDSL (It sounds like your exchange supports this, but you'll need to spend about R2 000 on new equipment and a different subscription to get it as it's not directly compatible with ADSL.

    In terms of your current speeds, though, you should definitely talk to Telkom. Either you're living a long way from the exchange or the copper on your line really needs replacing. Chances are they'll simply move you to a cheaper 4Mbps subscription though.
  • Hi, I ran the adsl checker and phoned Telkom, they both indicate my max line speed is 10mbps I have also run the diagnostic tool as per your post and entered my attenuation of 20 db. My issue with this is that the diagnostic tool indicates that I am approx 1.4km from the exchange. However I know for a fact that there is a MSAN 600m down the road from me.

    This is confusing as Telkom are adamant that we don't have an exchange that is VDSL capable.
    The phone centre told me that they wont be able to give indication when switch will take place, is there a place I can contact in order to find out when the MSAN in our street will get connected or go live.
  • DenniesDennies Mpumalanga
    Hi i am currently looking on upgrading to 10mbps. But there is something i dont understand. It says my maximum speed available in my area is 4Mbps(Copper) but my current service speed is 10Mbps.
  • MarcMarc Milnerton
    Hi. My current line is10Mbps but is only synchronising at 6144kbps. Phoned Telkom today to query this and said my line was only synchronising at 6144Kbps. Told them to increase to 10Kbps, which they done, but still is synchronising at 6144kbps. The downstream line attenuation is 10.6db. Speed test is showing me a download speed of 5.3Mbps.

    As far as I understand a downstream line attenuation of under 20db is extrememly good and means you are close to the exchange. Therefore my line should be synchronising at about 8000kbps if not more..

    Am I wrong? If not, what can i do to improve my line speed?
  • Can someone please explain this to me.

    These are from my modem/router:

    Bandwidth (Up/Down) [kbps/kbps]: 512 / 1.536

    Output Power (Up/Down) [dBm]: 1,8 / 4,6

    Line Attenuation (Up/Down) [dB]: 14,5 / 25,0

    SN Margin (Up/Down) [dB]: 12,0 / 32,3

    And this is from Telkom's ADSL Checker

    ADSL Availability
    Service Available
    Maximum speed available in your area 2Mbps (Copper)
    Your Current Service speed 4 Mbps

    Thanks in advance.
  • Please comment on my stats: Mode: ADSL_2plus
    Type: ATM
    Status: Up

    Downstream Upstream
    Line Coding(Trellis): On On
    SNR Margin (dB): 109 120
    Attenuation (dB): 590 370
    Output Power (dBm): 152 41
    Attainable Rate (Kbps): 2956 1015
    Rate (Kbps): 2496 511
    D (interleaver depth): 1 1
    Delay (msec): 0.25 0.24

    HEC Errors: 0 72
    OCD Errors: 0 0
    LCD Errors: 0 0

    Total ES: 0 0
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