Line attn changed from 47 to 40 db??

When BT changed me from tiscali LLu to BT Max the downstream attenuation, on my line changed
from 47 to 40 db. Would any one know a possible reason why?
ADSL Link Downstream Upstream
Connection Speed 7616 kbps 448 kbps
Line Attenuation 40 db 12.5 db was previously 47 downstream 10upstream
Is there any adjustment that BT can perform at my exchange prior to putting the adsl on the line.
Barry King

Did you change routers at the same time? Routers are not very accurate in measuring attenuation so different routers can vary quite a lot, especially different models.

No its the same router. The figures with tiscali attenuation was the same down and up, every time, when i logged in to the router.
The attenuation figures with BT, are also the same all the time, down and up when i log in to the router 40db down 12 .5 up every time.
My observation i have now got a reduced attenuation of 7 db downstream and an increased attenuation of 2 .5 upstream.
So can, or do, BT adjust the attenuation figures at the exchange if it helps my exchange is Fazeley Staffordshire.
Barry King

BT cant change the attenuation at the exchange, its a factor of the line itself, although as pointed out, some routers do differ from one another.
Maybe the tie cables to the LLU equipment were very long or there was a poorer termination on the LLU service n the exchange.

Ok i take the point that the line is a physical entity and cannot change from my house to the exchange.
During the good old days 1999 i had dialup and was having trouble with connection BT told me that they were going to increase (dont remember)on my line this cured the problem
I noted at the time that the the tone when i lifted the receiever had got louder and faster would BT have reset this when they put adsl on my line.
Please dont say has it returned to how it was in 1999 i cannot tell (old age)pardon what did you say!!?

That would have been the audio gain on the PSTN service. It would have no effect on broadband .

OK thanks so forget that. And if nobody else has any suggestions.? My final comments are thank you all, and it works fine.

Just one idea. The only accurate way to measure attenuation is to measure the signal strength of the input and the output. The ration between these (input over output) is the attenuation. The router only knows the output. It has to guess or assume the input strength.

A high loss link for the LLU connection could explain a lower than estimated input. Perhaps BT are providing a stronger signal.

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It has to guess or assume the input strength

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No it doesn't - the DSLAM tells it.

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And if nobody else has any suggestions.?

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Can you post the sync speeds and SNR margin before and after? Changes in these may give a clue.