question on DSL signal

Derek Ragona derek at computinginnovations.com
Tue Feb 5 09:03:31 UTC 2008


At 02:01 PM 2/4/2008, David Banning wrote:
>I run a small FreeBSD server with a standard DSL line. I have it ping
>the ISP every five seconds, and when it doesn't ping it logs the
>results.
>
>I notice very inconsistent results. Sometimes it's up for a week
>without a single drop, while other times it's up for 30 seconds,
>down for a minute, up for 2 minutes, down for 1.  That can go on
>for 10 hours, and then maybe it's stable again for a day or so.
>It's always appears to be the DSL signal itself, as I can see the
>modem sync light starts flashing when the signal goes down.
>
>To end any possibility of the phone company pointing their finger
>at the wiring in my house, I put the DSL modem right at the phone
>connection block where the line enters the house and then called
>them. Problem persists.
>
>The phone company say they have replaced lines all over the
>neighborhood while trying to fix the problem.  Eventually the
>connection becomes stable, the phone company declares that they
>"found the problem", but when he's gone, the trouble starts again.
>
>Now knowing how common this is,  I installed the same logging system
>at another company's server, that is located a few miles away. Guess
>what?  Same drop-in drop-out problem.
>
>To any average computer user, these lines might appear normal -
>when a page stops loading for a minute they just live with it, and
>forget about it.
>
>So here's my question:
>
>1. is there anyone who has a lot of experience monitoring DSL lines
>    that can tell me how common this is?

It is fairly common as the number of DSL providers is large, but they rely 
on the copper wires in place that may or may not be well maintained that 
are usually owned by another firm.  So getting the copper actually fixed 
can take a lot of persistence and patience.  Often these lines are from old 
voice circuits that were not nearly as demanding as DSL.  Worse, at least 
around me in the midwest, often indoor boxes and such are used outside 
which causes a lot of issues with digital lines.


>2. Is there any way to avoid it?

Get all new wiring in place.


>3. I have used three different DSL modems, but the are all home
>    quality: an Alcatel Speed Touch, a Speedstream 5260,
>    and a Westell Wirespeed. Would spending more money on
>    another type of modem help? If so, what is recommended?

I'm not sure if the modems really matter as it is likely a "noisy" line 
either from other drops still in place, bad junctions, or just old wires 
getting crosstalk.

Keep a log of problem times, noting the weather, time of day, and anything 
else that could be a factor.

         -Derek

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