Tony Whitmore <tony@???> wrote:
> Apparently BT have rated my line as stable at
> 1Mbps. I'm about 2.2 miles from the exchange via
> road.
But the cable route may be longer, unfortunately.
Some routers report their Tx/Rx data - you may
need the command line. My Speedtouch 546 reports
this:
Downstream Upstream
Margin [dB] : 15.5 24.0
Attenuation [dB] : 19.0 10.0
OutputPower [dBm] : 19.5 12.0
The noise margin and line attenuation are the
critical figures. If your line is long, or in bad
repair, the attenuation will be high, degrading
the noise margin. The modems at either end will
drop their data rates to push the margin up to a
level where bit errors are reasonable.
It may be worth talking to PlusNet about your line
rate negotiation history. Zen allow you to look at
this through their control panel - your ISP may
offer something similar. That will show if you're
consistently getting a low data rate.
> I don't know whether there's anything one can do
> to get BT to look at replacing old cabling? Or
> re-kick off the line/speed testing process?
It might be worth checking for obvious damage
above ground on your property - you might be able
to convince BT to replace that. Also look at the
quality of your internal wiring - after the master
socket - and consider the quality of your ADSL
filter. For the wiring, I treat it like it's Cat5.
I doubt BT will do much to the wiring below
ground, unless you can find a way to...
accidentally break the voice service. :-)
> The question now is, if I only get 1Mbps out of
> 8Mbps, would I get a higher speed with ADSL2? Or
> would I just be getting 1Mbps out of 24Mbps?
It's impossible to predict - ADSL uses a band up
to 1.1MHz, whereas ADSL 2+ extends to 2.2MHz. If
your line's response is better at higher
frequencies - it could be - you'll get a better
data rate.
The Wikipedia article,
http://en.wikipedia.org/wiki/Adsl
has some info on the differences, and this
article
http://en.wikipedia.org/wiki/ITU_G.992.1
links to a couple of data rate graphs versus line
length,
http://upload.wikimedia.org/wikipedia/en/1/1b/ADSL_Line_Rate_Reach.gif
and line attenuation,
http://upload.wikimedia.org/wikipedia/en/6/65/ADSL_Line_Rate_Attenuation.gif
Nick.
--
Nick Chalk ................. once a Radio Designer
Confidence is failing to understand the problem.
%0A>%20%0A>%20>%20The%20question%20now%20is,%20if%20I%20only%20get%201Mbps%20out%20of%0A>%20>%208Mbps,%20would%20I%20get%20a%20higher%20speed%20with%20ADSL2?%20Or%0A>%20>%20would%20I%20just%20be%20getting%201Mbps%20out%20of%2024Mbps?%0A>%20%0A>%20It's%20impossible%20to%20predict%20-%20ADSL%20uses%20a%20band%20up%0A>%20to%201.1MHz,%20whereas%20ADSL%202+%20extends%20to%202.2MHz.%20If%0A>%20your%20line's%20response%20is%20better%20at%20higher%0A>%20frequencies%20-%20it%20could%20be%20-%20you'll%20get%20a%20better%0A>%20data%20rate.%0A>%20%0A>%20The%20Wikipedia%20article,%0A>%20%20%20%20http://en.wikipedia.org/wiki/Adsl%0A>%20has%20some%20info%20on%20the%20differences,%20and%20this%0A>%20article%0A>%20%20%20%20http://en.wikipedia.org/wiki/ITU_G.992.1%0A>%20links%20to%20a%20couple%20of%20data%20rate%20graphs%20versus%20line%0A>%20length,%0A>%20%20%20%20http://upload.wikimedia.org/wikipedia/en/1/1b/ADSL_Line_Rate_Reach.gif%0A>%20and%20line%20attenuation,%0A>%20%20%20%20http://upload.wikimedia.org/wikipedia/en/6/65/ADSL_Line_Rate_Attenuation.gif%0A>%20%0A>%20Nick.%0A>%20%0A>%20--%20%0A>%20Nick%20Chalk%20.................%20once%20a%20Radio%20Designer%0A>%20%20Confidence%20is%20failing%20to%20understand%20the%20problem.%0A>%20%0A>%20%0A>%20%0A>%20 "Reply to this message")
