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Level of the DSL pilot tone?

Discussion in 'Electronic Design' started by Joerg, Aug 17, 2006.

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  1. Joerg

    Joerg Guest

    Hello Folks,

    After two frustrating hours on the phone with my ISP, dodging their
    excuses and their "Oh, it's got to be this other problem" I want to be
    able to diagnose some DSL stuff for myself. IOW measure DSL signal
    levels versus noise. AFAIK there is a pilot tone at 276kHz or sometimes
    138kHz for downstream and another one at 69kHz for upstream.

    Question: What are the min-max levels for those pilot tones?

    Reason why I want to be able do that is the extreme wait on the phone
    when something happens, questionable competence of support personnel,
    and their tendency to offload a problem to their HW service. "Oh, it's
    got to be your line" and then they try to make you pay. I know for sure
    that my current email receiving issues are not telco HW related but it
    sure would be nice to tell them "Hey, I measured these dBV levels for
    the pilot tones so it can't be".
  2. Doubt if that makes a difference to them. But if you can surf the
    web, your DSL line is clearly working. That should be a strong enough

    I had similar problems with providers. What fixed it, was changing to
    another provider, and yes, it costs more. I can't really say their
    helpdesk is better, because everything simply works brilliant - no
    need to call them. Even the bills are correct and always on time.

    Same thing with hosters. Tried a few cheap ones and they all really
    drove me mad. Now I pay a bit more, but everything works like a
  3. It doesn't work.
    If they try stalling on a "it's your equipment/line/town ..." script, I
    usually lie and tell 'em I'm monitoring a comm's analyser that's saying the
    equipment and line are OK. Just blows by 'em, they move onto the next moron
  4. Jim Thompson

    Jim Thompson Guest

    Won't do you any good...

    If you're too dumb to flip burgers, you pump gas

    If you're too dumb to pump gas, you work for Fry's

    If you're too dumb to work for Fry's, you answer phones for an ISP ;-)

    I got so tired of getting the, "Did you reboot your PC", then, "Did
    you reboot your router", followed by, "Did you reboot your cable
    modem", that I wrote to executives at Cox... alluding to how I would
    work to get them declared a utility by the Corporation Commission, and
    thus subject to refunding for failure to provide service. That
    apparently got me on an "honesty list" where they just 'fess up when
    there's a system problem.

    Like yesterday I received....

    "Dear Cox Customer,

    As part of a routine maintenance earlier today, August 15, we had an
    issue affecting some email boxes. As a result, you may have
    had difficulty accessing your mailbox earlier today, and you may be
    seeing fewer messages in your mailbox at this time.

    By late Tuesday evening or early Wednesday morning we expect all of
    your messages to have been delivered, including any sent during the
    day today. No mail should have been lost as a result of this issue. If
    you did not receive an email you were expecting by Wednesday
    afternoon, please contact the sender and ask them to re-send.

    At this time all restoration methods are underway, and there is no
    need to call.

    Thanks for your patience,
    Cox Communications"

    I just loved that "...there is no need to call" ;-)

    ...Jim Thompson
  5. Joerg

    Joerg Guest

    Hello Frank,
    T'is what I told him. But you are right, it wouldn't have made a
    difference if I had the levels because this guys didn't seem to have a
    clue. After I finally busted my way through some corporate barrier an
    engineer "found" that they are having issues with a server and a whole
    crew is currently pulling a late shift to fix it. He also said my SNR
    was kind of low which I'd like to see for myself. But it's certainly not
    the root cause of not getting emails.

    Well, it's better in the EU. More competition. Here, you are often
    dealing with de-facto monopolies.

    I use 1and1. Very nice. Only a few hours outage in two years but the
    east was being pummeled by snow storms when that happened.
  6. Joerg

    Joerg Guest

    Hello John,

    Ah, great idea!
  7. Joerg

    Joerg Guest

    Hello Jim,
    Maybe I should do that now.

    Just received a similar one from IEEE about why the virtual communities
    are incommunicado for a while. They, ahem, gasp, forgot to renew the
    domain registration. Ouch!
  8. Eeyore

    Eeyore Guest

    You have my sympathies. After nearly 2 months of doing battle with my ISP, I'm
    off to another one.

  9. Eeyore

    Eeyore Guest

    Sounds like my ISP too ( shortly to be ex-ISP )

  10. Sounds sortof like Earthlink when I had them. They had a very good system
    status page that I would go to thru Juno when things went south.

  11. I don't know if you are far away from the hub. Here, when you apply for
    (A)DSL they first measure/test your line, also to see what the maximum
    possible speed will be. The highest speed abo's aren't possible when
    you're too far away from the hub, or when there is some other issue
    with the actual copper wires ;)
  12. Do you have a router? I just point my browser at the
    router's dq address and it returns all its measured
    connection diagnostics, as a web page....... upstream/
    /downstream connection speeds, transmit/receive power
    levels, SNR's, round trip ping time to my ISP, etc.

    It is presently showing.

    Reserved Bandwidth (kbit/s) up/down = 288/2272.

    Output Power (dBm) up/down = 12.0/18.0.

    Attenuation (dB) up/down = 26.0/41.0.

    Noise Margin (dB) up/down = 28.0/20.5.

    Ping Time (20 bytes) = 14mS.
  13. Joerg,
    your internet appears to be working. Why don't you
    just get another account ? Such as from gmx ?
    Costs nothing, and they also provide an SMTP for
    authenticated remote users and a web interface.

  14. Joerg

    Joerg Guest

    Hello Frank,
    Same here. I looked at the analyzer when they did the line check before
    signing me up and the SNR looked surprisingly good. However, in the US
    there is an unfortunate habit in that contractors often bury the phone
    lines in the same trench with the power lines. All it takes is a noisy
    new load on the power grid (not necessarily in your own house) and the
    SNR goes to pots.
  15. Joerg

    Joerg Guest

    Hello Tony,
    Interesting. I don't know if my router (SMC Barricade) has that feature,
    have to check. The Westell Wirespeed modem is a separate box and AFAIR
    not very "talkative" to end customers.
  16. Jim Thompson

    Jim Thompson Guest

    Huh? That's certainly not legal in Arizona.

    ...Jim Thompson
  17. Joerg

    Joerg Guest

    Hello Rene,

    Well, I have a web site hosting provider and email through there. It's
    currently set to forwarding and probably this weekend I'll swing it
    around to a direct connection into my email client because they are more

    Email through a web interface would not work for me as they typically
    limit files sizes to 1-2MB. CAD stuff is larger than that.

    Surprise: Just got an automated message that they have fixed my line. I
    did hear a truck rumble at the end of our street, maybe some connection
    got a bit loose. But it has nothing to do with missing or returned
    email and I wish their customer phone support folks would be a bit more
    educated about how things work. Wanted to look at the online site they
    mentioned to see what the problem was: "The online Repair Center is
    currently unavailable." Duh! Guess the next thing broke :-(
  18. Joerg

    Joerg Guest

    Hello Jim,
    Before building a fence a few years ago I dutifully called Digalert
    (wish all the "pros" would also do that, sigh...) and when the phone
    guys traced it along the same path as the utility I asked them whether
    that means it's the same trench. "Yup, like usual".
  19. Hey, that is interesting, I have this:

    DSL Flavour = ADSL over POTS
    Reserved Bandwidth (kbit/s) up/down = 512 / 3072
    Uptime = 19d 20:36
    kBytes Tx/Rx = 258885 / 1967996
    Output Power (dBm) up/down = 11 / 20
    Attenuation (dB) up/down = 10 / 21
    Noise Margin (dB) up/down = 23 / 30
    Vendor Id (local/remote) = ALCB / BDCM
    Loss of signal (local/remote) = 0 / 0
    Loss of power (local/remote) = 0 / 0
    Loss of framing (local/remote) = 0 / 0
    Errored Seconds (local/remote) = 0 / 0
    Loss of link (remote) = 0

    Not that I have any idea how to interpret this.
  20. gives me some data about my cable modem:

    Name WebSTAR DPC2100
    Modem Serial Number 201455763
    Cable Modem MAC Address 00:11:e6:c6:f5:1b
    Hardware Version 2.0
    Software Version v2.0.2r1244-050319
    Receive Power Level -5.4 dBmV
    Transmit Power Level 38.5 dBmV
    Cable Modem Status Operational

    Service to my country? Been there, Done that, and I've got my DD214 to
    prove it.
    Member of DAV #85.

    Michael A. Terrell
    Central Florida
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