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Aspiring Contributor
Message 1 of 6

ADSL line reset?

Oh fonts of knowledge, is there a set amount of time at we having work done that my line speed should improve?
We've had a new faceplate installed today but according to the engineer there were issues aplenty at the exchange, which she sorted. Our download as peed is less than half a mb as before but i assume as we'd been having dropouts the line had been limited previously.
I have a daughter crawling the walls as Easter holidays have arrived and YouTube is beyond her currently.
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Distinguished Sage
Message 2 of 6

Re: ADSL line reset?

your speed should improve after 3/5 days providing you maintain a stable connection
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Aspiring Contributor
Message 3 of 6

Re: ADSL line reset?

Cheers for that.
I'm on day 3, so wait for the full 5 before contacting BT again? Can that be done here or does it have to be through the flipping contact centers?
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Aspiring Contributor
Message 4 of 6

Re: ADSL line reset?

Have just rediscovered how to obtain line stats:


4. Board version:

BT Hub 5A
5. DSL uptime:1 days, 05:38:47
6. Data rate:1132 / 575
7. Maximum data rate:1124 / 8120
8. Noise margin:5.9 / 26.8
9. Line attenuation:16.7 / 31.9
10. Signal attenuation:16.7 / 29.5


Looks like we had another drop out yesterday morning, just two days after the engineer visit.


Could anyone advise if this is likely to be an ongoing concern and will be limiting out line if it continues?





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Distinguished Sage
Message 5 of 6

Re: ADSL line reset?

Why has my speed suddenly dropped?
ADSL connections (see notes about Infinity at the end), and the notes by RogerB
Changes in your connection speed are automatically managed by the exchange equipment, using a process called
Dynamic Line Management (DLM).
Its purpose it to give you the best speed possible, without introducing a lot of errors back into the BT network.
These errors impact on other users, and can slow their connection down, as your data packets have to keep being resent.
This is a continous process, but certain things can cause it to make drastic changes to your connection speed.

These can include the following:-
You could have also been recently moved from ADSL max to ADSL2+, this would mean that the line
would have to re-train again, and must be left undisturbed  for at least 10 days.
If you keep restarting or disconnecting your BT Home hub, then the exchange equipment will see this as a fault condition, and reduce your connection speed, in an attempt to stabilise your line.
You have recently had a fault on your line which has just been fixed.

Sometimes a single interruption to your line can cause this too, especially if it generates a large error burst.
The effect is that you get placed in a low banded speed profile, and you will notice that your downstream margin is high, usually over 15dB.
The lower the banded speed profile, the quicker it will recover, but it could take up to a month before the fullspeed is recovered.

If you want your speed to recover, then these are the steps you need to take.
DO NOT restart or disconnect the power to your BT Home Hub.
DO NOT disconnect your BT Home hub from your phone line.
Leave everything alone for at least 10 days, so that the exchange can record a stable connection.

During this time, the exchange may drop the connection, and re-establish a faster connection.
If you use the BT Speedtester, then do not restart the BT Home Hub, even if it tells you to.
If after 10 days your speed does not increase, then please return to your forum post.
showing  that you have 10 days of connection time, then the problem can be escalated.

You can calculate your final speed by using this website.

Maximum speed calculator
Infinity connections
A similar process is applied to the connection between the Infinity cabinet, and the Openreach modem.
You cannot view that connection information, but the same thing applies, do not restart or disconnect the Openreach modem.
The BT home hub only acts as a router, and restarting it will not affect your physical connection speed to the cabinet.
Additional information by forum member RogerB
BT broadband is line adaptive, if you have a good line, you get good broadband , BUT consider this, you only get good broadband
from the outset, if you let the exchange "train" the connection, when it is new, simply because it has to try various methods of modulation.
And once it is running at full speed and set the MSR (maximum stable rate) provided you don't keep disconnecting the router, it will stay that way.
So two important things:  ALWAYS leave the router on, 24/7 and DO NOT impede the training process which can take up to 10 days.
The reasons are vaguely the same for both scenarios:  DLM trains the connection during setup, and DLM runs the connection in a similar but different mode once it's running.
And the most common issue apart from line faults in causing poor broadband is FREQUENT RESETS and DISCONNECTIONS of the router or hub, because if you interupt line management it will demote the line profile if done to excess, with often time consuming efforts and long waits to get it back.
BT don't punish users indiscriminently by making them wait for their broadband speed to come up, but the line management is in place  to DEFEND the network against bad and corrupted data, and if the exchange sees your line being reset too often it assumes a fault,
whereby your linespeed is demoted, and often profoundly so.
Also, because the exchange can't tell the difference between you messing around resetting all the time, and a real line fault, it assumes (using logic) the worst and demotes the line profile.
If you get a real line fault and the noise margin increases, the linespeed will decrease, it's normal, again it's a defence to help give you a service  allbeit a depleted one, and at the same time stop corrupted data getting back to the exchanges.
But unfortunatlely it's at this point when people in general start to become frustrated,  and guess what?
They then start to reset the router in an attempt to "repair" the connection. And in doing so, impede the line management from promoting the linespeed again. (providing any fault is or was fixed).
And to summarise, if the connection is left to run unimpeded, no excess resetting, and left to its own devices, it actually benefits from the good line

history that the exchange has accumulated for your connection, simply because the attention span by the line management is not so profound when it does bite the dust, for whatever reason.
So regardless of the opinions of some, switching off broadband routers is NOT a good idea, not if you want consistent broadband and a good line rate.
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Message 6 of 6

Re: ADSL line reset?

Great Advice, but my modem is left powered on continuously and is either turning itself off or the line keeps dropping out. My speeds have dropped from 142mbps to 97 mbps in the last 14 days since we had the engineer out for a third time!!!! So what is causing my speeds (which I am paying for) to keep dropping below your 100Mbps guarantee. Is it the router or a bad line. I've been told both are fine. The router is resetting approx every couple of days all by itself. Didn't have this trouble with my Home Hub 5 I now have a smart hub 2 which I was told I had to buy as my Hub 5 couldn't cope with the faster speeds. Is this true??



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