Max DSL and line length

Will the introduction of Max DSL have any effect on the current limitations
of line length? I can only receive 1MB at present because of the distance
from the exchange. Is there any hope that I will be able to have increased
speed when my exchange is enabled for Max DSL?

TIA,
Terry

 

Yes, you will most probably see some sort of increase as MaxDSL is
supposed to sync at the highest possible speed that your line is
capable of. Currently, BT limit connection speeds based on attenuation,
but these can be rather conservative.

If you post your line stats from your ADSL modem, its possible to
guestimate the approximate speed your line is capable of. Its the SNR
(Noise Margin) & Attenuation thats needed.

 

Or do it yourselfe here:- http://212.23.23.177/calc.htm

 

Interesting.
However, it asks for SNR, whereas some modems report SNR margin.
Is there a simple conversion? Add 2dB for example?

 

Thanks. How do I check my line stats? I'm using a Netgear DG834G and when I
log in I don't see anything relevant. Do I need some other software?

 

Likewise my router does not have a figure for SNR, but has DS and US
margins. Would that be the same?

 

Log on to the Netgear Router
Goto Router Status Page.
At bottom of page click on Show Statistics. New window opens with the info.

 

Its the DS (Downstream) statistics you're after.

 

Max DSL isn't an improved technology, it's simply BT relaxing their own
guidelines as to what speeds they will support for a given line
attenuation. These guidelines have previously been set on the low side,
reportedly to give what BT regarded as an acceptable level of
reliability, but also perhaps with a view to being able to relax them in
order to sell a new 'Max DSL' product to maintain competitiveness
against growing customer interest in LLU products.

So yes there is certainly a chance that you will be able to get higher
speeds, but possibly at the expense of reliability, and nothing you
couldn't already get from an LLU ISP if you were lucky enough to have
LLU support at your exchange.
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Thanks for your reply, Paul.
When I do what you suggest all I see is a table headed System Uptime with
columns headed Port, Status, TxPkts, RxPkts, Collisions, TxB/s, RxB/s and
Up Time. I'm using firmware 1.01.00.00. Yes, I know there are later
versions but this one works very reliably for me.

 

Later: I've upgraded the firmware to v 1.05 and can now see the line stats.

 

Here are my line stats at 1152 kbps:
Line attenuation 48db
Noise margin 22db

What do you think?

 

You should be able to have a reliable 2Mb connection, possibly as much as
3Mb.

Dan.

 

Based on those stats, using ADSL1 technology (which is what MaxDSL is)
the max your line could support is approx 4-4.5Mbps. It depends on
what BT are setting the "target SNR" as on this new MaxDSL service, as
that will be what determins your sync speed. I reckon at worst, you'll
be looking at 3Mbps.

When ADSL2+ comes along (well, its already here if you have an ISP with
their own equipment installed at the exchange using LLU), you'd see a
slight increase in sync speed on top of that above..

 

Thanks for your replies DLMatthews and Daniel. Very helpful.

 

My exchange has just been MaxDSL enabled, and my SNR has dropped from
about 15db to 6db, attenuation is 55db and line speed has stay fixed at
1152kb/s. Nothing has changed at my end of the connection.

Any reason why BT carrying out 'the work' would have reduced my SNR?

pzboyz.

 

More probably part of your cable has been changed due to uplift works,
or your neighbour has bought a big shiney new plasma TV, or your PC
power supply is starting to throw a wobbly, same for your router power
supply. There are a lot of things which can affect your SNR, the
majority of them happen to be outside BT's control...

 

It reminds me of that old not the nine o'clock news spoof sketch where
the BBC were being blamed for no milk in the fridge and tripping over
the pavement. 'It is not the fault of the BBC'. That said the latter
could well be the fault of BT.......

 

How long have you worked for BT?

Euan.

 

Not long enough for a decent pension but to long to keep my sanity