Do BT keep logs of test results?

Back in the day (Nov 2003), I got ADSL installed, when the threshold for
512K attenuation was 60dB.
AIUI, 60dB is now the limit for 1Mb.
However, I believe my line has got a couple of dB noisier.
Will they simply attempt the upgrade, based on records?

Ian Stirling wrote:
> Back in the day (Nov 2003), I got ADSL installed, when the threshold for
> 512K attenuation was 60dB.
> AIUI, 60dB is now the limit for 1Mb.
> However, I believe my line has got a couple of dB noisier.
> Will they simply attempt the upgrade, based on records?

I believe they will, as long as Pussy-Not don't put their foot in it.
You know Attenuation is different to SNR, don't you?

> Back in the day (Nov 2003), I got ADSL installed, when the threshold for
> 512K attenuation was 60dB.
> AIUI, 60dB is now the limit for 1Mb.
> However, I believe my line has got a couple of dB noisier.
> Will they simply attempt the upgrade, based on records?

The SNR (or "noise margin") is the important thing. So long as the SNR is
above about 15 dB, then they should be able to upgrade you, regardless of
the attenuation (unless it's really really bad).

tim <(E-Mail Removed)> wrote:
> Ian Stirling wrote:
>> Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>> 512K attenuation was 60dB.
>> AIUI, 60dB is now the limit for 1Mb.
>> However, I believe my line has got a couple of dB noisier.
>> Will they simply attempt the upgrade, based on records?
>
> I believe they will, as long as Pussy-Not don't put their foot in it.
> You know Attenuation is different to SNR, don't you?

Yes, it was my understanding that BT have a limit of 60dB on 1Mb (and
43dB for 2Mb), and no specific SNR based figures.

On 21 Jun 2005 22:24:24 GMT,it is alleged that Ian Stirling
<(E-Mail Removed)> spake thusly in uk.telecom.broadband:

>Yes, it was my understanding that BT have a limit of 60dB on 1Mb (and
>43dB for 2Mb), and no specific SNR based figures.

Ooh. I have a reading of 53db for downstream attenuation, and
30.something for upstream on a 512k, allegedly 2200m from the exchange
(probably closer to 3000 as the cable flies).

*looks sideways at the 1Mb service*

--
The most exciting phrase to hear in science, the one that heralds new discoveries, is not "Eureka!", but "That's funny..."
- Isaac Asimov

Chris Jones wrote:
>>Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>>512K attenuation was 60dB.
>>AIUI, 60dB is now the limit for 1Mb.
>>However, I believe my line has got a couple of dB noisier.
>>Will they simply attempt the upgrade, based on records?
>
>
> The SNR (or "noise margin") is the important thing. So long as the SNR is
> above about 15 dB, then they should be able to upgrade you, regardless of
> the attenuation (unless it's really really bad).
>
>

The SNR is unimportant as long as its above 6dB.
Its the attenuation which is the important thing.

tim <(E-Mail Removed)> wrote:
> Chris Jones wrote:
>>>Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>>>512K attenuation was 60dB.
>>>AIUI, 60dB is now the limit for 1Mb.
>>>However, I believe my line has got a couple of dB noisier.
>>>Will they simply attempt the upgrade, based on records?
>>
>>
>> The SNR (or "noise margin") is the important thing. So long as the SNR is
>> above about 15 dB, then they should be able to upgrade you, regardless of
>> the attenuation (unless it's really really bad).

> The SNR is unimportant as long as its above 6dB.
> Its the attenuation which is the important thing.

Not technically, but possibly as a matter of BT policy.

Ian Stirling wrote:
> tim <(E-Mail Removed)> wrote:
>
>>Chris Jones wrote:
>>
>>>>Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>>>>512K attenuation was 60dB.
>>>>AIUI, 60dB is now the limit for 1Mb.
>>>>However, I believe my line has got a couple of dB noisier.
>>>>Will they simply attempt the upgrade, based on records?
>>>
>>>
>>>The SNR (or "noise margin") is the important thing. So long as the SNR is
>>>above about 15 dB, then they should be able to upgrade you, regardless of
>>>the attenuation (unless it's really really bad).
>
>
>>The SNR is unimportant as long as its above 6dB.
>>Its the attenuation which is the important thing.
>
>
> Not technically, but possibly as a matter of BT policy.

Yes technically, as the attenuation is a function of the line length.

tim <(E-Mail Removed)> wrote:
> Ian Stirling wrote:
>> tim <(E-Mail Removed)> wrote:
>>
>>>Chris Jones wrote:
>>>
>>>>>Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>>>>>512K attenuation was 60dB.
>>>>>AIUI, 60dB is now the limit for 1Mb.
>>>>>However, I believe my line has got a couple of dB noisier.
>>>>>Will they simply attempt the upgrade, based on records?
>>>>
>>>>
>>>>The SNR (or "noise margin") is the important thing. So long as the SNR is
>>>>above about 15 dB, then they should be able to upgrade you, regardless of
>>>>the attenuation (unless it's really really bad).
>>
>>
>>>The SNR is unimportant as long as its above 6dB.
>>>Its the attenuation which is the important thing.
>>
>>
>> Not technically, but possibly as a matter of BT policy.
>
> Yes technically, as the attenuation is a function of the line length.

Attenuation is a loose factor of line length, line type,..
It's not particularly important. SNR margin at a given speed is the only
really important number.

Ian Stirling wrote:
> tim <(E-Mail Removed)> wrote:
>
>>Ian Stirling wrote:
>>
>>>tim <(E-Mail Removed)> wrote:
>>>
>>>
>>>>Chris Jones wrote:
>>>>
>>>>
>>>>>>Back in the day (Nov 2003), I got ADSL installed, when the threshold for
>>>>>>512K attenuation was 60dB.
>>>>>>AIUI, 60dB is now the limit for 1Mb.
>>>>>>However, I believe my line has got a couple of dB noisier.
>>>>>>Will they simply attempt the upgrade, based on records?
>>>>>
>>>>>
>>>>>The SNR (or "noise margin") is the important thing. So long as the SNR is
>>>>>above about 15 dB, then they should be able to upgrade you, regardless of
>>>>>the attenuation (unless it's really really bad).
>>>
>>>
>>>>The SNR is unimportant as long as its above 6dB.
>>>>Its the attenuation which is the important thing.
>>>
>>>
>>>Not technically, but possibly as a matter of BT policy.
>>
>>Yes technically, as the attenuation is a function of the line length.
>
>
> Attenuation is a loose factor of line length, line type,..
> It's not particularly important. SNR margin at a given speed is the only
> really important number.
>

As long as SNR is 6 or above it doesn't matter - the speed is
immaterial. On the other hand the limits for acceptable line length and
therefore attenuation, are strictly defined by speed.