On Thu, 01 May 2008 20:46:45 +0100, LR <lrme@privacy.net> wrote:

>I have never seen it work like that,my original DSL line never varied in
>speed for 2 years until they changed the equipment in the CO and doubled
>my line speed. When I started with MaxDSL the sync speed started high
>and worked down until it was stable and if it then remained stable for
>several days an increase in sync speed would be tried etc... see the
>link I provided.

In California, PBI/SBC/AT&T does it by slowly ramping up the speed as
indicated. I recently installed a 6MBit/sec (6000/640) DSL line.
Using the SBC speed test and Web100 sites, the speed at about noon was
something like:
kbits/sec
Day 1 2000/200
2 2000/200
3 4500/400
4 2000/200
5 4500/380
6 5200/400
7 5500/500
and has held steady since then. I can get the exact numbers if anyone
really wants them. AT&T was obviously experimenting with different
configurations. Attached to the DSL modem is a warning sticker than
demands that the modem be powered on continuously for the first 10
days.

I've had the displeasure of cleaning up the mess left by customers
that plug in their DSL modem, and simultaneously make a mess of the
DSL splitter or DSL filters. With bad wiring, or badly configured
filters, the adaptive equalizers cannot do their job. The result it
low signal levels and a high error rate. The DSLAM configures the
line for the slowest possible speed. I usually arrive on the scene
after the 10 day training period, and end up calling AT&T support (in
India) begging them to setup line retrain the line. In the past, they
would not do it unless I claim something has drastically changed at
the customers site, or that I threaten cancellation if the speed
doesn't increase. If you're really good, you can beg them for a copy
(via fax) of the line report. Here's a sample of an old 6000/384 DSL
line:
<http://802.11junk.com/jeffl/crud/DSL_line_stats.gif>
You can also get many of these statistics from the internal web
configuration page of your DSL modem, or using various tools and
utilities. For example, this is a sample of what one can extract from
an old Efficient 5260 DSL modem:
<http://groups.google.com/group/ba.internet/msg/e35b9b0f232f9551>

>The modem used to be switched on and off because at that time I was
>testing a variety of modem/router combo's over a period of time and I
>only had one DSL line. I no longer do testing of these at home so my
>modem only gets switched off when we are away for several days.

That's fine. I have no clue how long a training window your DSL
service allows. You may want to ask. In general, if I expect to be
doing wiring after the DSL is initially installed, I will install just
the DSL modem in the best possible location (near the Demarc) and
leave it on while doing the wiring. That's probably overkill as
leaving the modem on over night is probably sufficient for testing
purposes.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558