CRAIGFIN

A quick question for the BT boffins. I currently have a 1.1mb ADSL Broadband service provided by Pipex through a BT line. I want to upgrade to a faster service but when I do the BT online check with my phone number the results come back saying they can only provide me with 500kbits/s. The same check using my postcode comes back with 3.5mb.
I am sure my line can handle more than they claim it can, as my neighbour has a lot faster speed than me, not sure exactly the speed though. This doubt is fuelled by the fact that Pipex is currently giving me 1.1mb, yet BT claim the line can only handle 500kbits/s. There is clearly a discrepancy somewhere.

Is the BT online check accurate?
Can I get BT to send an engineer to physically check or replace the line at all, as opposed to doing an online check that I have no confidence in?

What are my options? (apart from moving, before somebody suggests it )

Cheers,

Craig.

Dark

iTrader: (1)

The broadband speed is governed by your distance from the exchange, the attenuation of the line and the signal to noise margin that can be maintained.

Does you existing router / modem display the line attenuation and signal to noise margin ? Most should have this capability. Note that these measurements should be made from the BT master socket, internal house wiring can have a huge impact upon adsl performance.

The ADSL Max service from BT will sync at the highest stable speed possible depending upon the line conditions and this can vary hour to hour and day to day.

Typically you should be able to achieve ~4Mbit/s with a 40dB line, ~2Mbit/s with a 50dB line and 0.5Mbit/s with a 60dB line.

Mark

CRAIGFIN

Dark,

Thanks for the reply. I've had a look through the diagnostics for my Alcatel Speedtouch 330 ADSL modem but I can't see anything that looks like what you described.

Craig.

Dark

iTrader: (1)

This site tells you how to find out !!

::. Kitz - Get your adsl line stats .::

The rest of the site also has some good reading.

Mark

CRAIGFIN

Mark,

I'll have a look, many thanks.

Craig.

CRAIGFIN

Okay,

I've done the procedure as per the above link. My results are as below.

Receive Attenuation = 54db
Receive Margin = 10db
Send Attenuation = 31db
Send Margin = 26db

Can anybody tell what me what this means in real terms?
Does the 40db figure that Mark mentions above for a 2mb speed refer to the Receive Attenuation or the Receive Margin?

Can anything be done to lower the noise on the line?
Do I have grounds to ask BT to replace the line?

Cheers,

Craig.

stara

Hi i am an ADSL openreach engineer (can't call ourselves BT engineers anymore due to equivalence rules.) Mark pretty much has covered what the problems are. Your only option is to go for a maxrate product, doesn't matter who your isp is or will be, the speed will be the same (although some LLU providers have their own exch racks in BT exchanges, they may offer higher speeds depending on what equipment they are using.) . You have posted a rec attn of 54db, this means you are either a fair distance from the exchange (4km+) or you are fed via aluminium cable, this figure determines your line speed. There is not much that can be done to improve this, just make sure you have no audible noise (i.e. crackling or buzzing) on your phone line, as this greatly affects your broadband speed. Your isp will not send an engineer to improve your line speed, they will only ask for us to attend if the line is performing slower than expected by the isp. Also note that a change to maxrate could possibly be perceived to be running slower than your previous fixed rate as a fixed rate product may have been erroring, maxrate will not allow itself to error, so will back it's speed off.

Also, one of the easiest and most efficient ADSL fixes is to fit a SSFP (basically it is a master filter, which filters all extensions at the cable entry point, the upsides are that all extensions are filtered reducing line loss and potentially increasing maxrate speeds, the downside is the router has to be plugged in at this point as the ADSL signal will only exist at this point.)

There should be no TEE'D wiring, i.e. extensions connected to the wiring before the master socket.

Plugin extensions are not recommended to provide ADSL due to the usually cheap quality and resulting noise issues.

The perfect ADSL circuit would be within 1km of the exch, have copper wires, have endless new dropwire (D/W10) or leadin, connected straight to NTE5 socket with no extension wiring. Or if extensions must be fitted, an SSFP is fitted to filter extensions.

CRAIGFIN

Stara,

Many thanks for taking the time to write a lengthy and complete explanation of my woes. Its put the issue to bed for me now. I guess I'm pretty much stuck with what I have for the time being. Is there any way I can trace where my exchange is? I would like to see, just out of interest, how far I am from it.

Cheers,

Craig.

root

If your neighbours are achieving good speeds and you are not you could try and get them to move your line onto a different pair in the cabinet on the street. It's not uncommon to have older and newer cables running from the exchange to the cabinet and you could be on a crappy old one.

Ray_li

none about because they are not Engineers

bobsabuilder

Sorry to hijack this thread - well ok I'll admit I'm not sorry at all

Using that link above I've got theses figures:

Up Stream Margin 29
Down Stream Margin 27

Up Stream Line Attenuation 35
Down Stream Line Attenuation 28

On a 2mb connection at present but been offered a free upgrade by the ISP of upto 8mb depending on line suitability.

So any ideas from the above info if my line is gonna be able to handle more than the present 2mb?

Cheers for any advice,

Bob

Dark

iTrader: (1)

Hi Bob,

Run your phone number through the BT adsl checker and see what it says but with those stats I would expect you to get 5-6Mbit/s on the BT ADSL Max service.

Regards, Mark

bobsabuilder

Cheers mark

GCollier

The Broadband Resource

CRAIGFIN

GCollier,

Many thanks for the link, it was exactly what I was after. I now know my exchange is 2 miles (3.3km) away from my house.

Craig.

Dark

iTrader: (1)

I also found this website which has a table of line length (line attenuation) against line speed.

-=| adsl.yesyes.info |=- - FAQ

Mark