Theres something amiss with your line as your downstream attenuation has dropped significantly, your line rate has increased to the maximum with an improved noise margin. You must have lost sync .

Not lost sync - the router confirms it's been up for over 2 hours.

No noticeable change as far as perceived speed goes.

Can't understand why the noise margin has gone up when the attenuation (= volume ?) went down ?

Also - what are "normal" noise margin figures ?

Lost sync since your earlier post , connection speed of 6784 kbps.
Attenuation isnt the the power of the signal but the loss over the line.
Less loss equals more signal received for a given power output.

OK - thanks. My amateur audio engineering getting in the way of my understanding (not for the first time).

All runnign ok until 13:30. Connection dropped completely. Came back up with the following ...

System Up Time 05:14:04
Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 7463 12726 0 4933 55946 00:05:12
LAN 10M/100M 93483 72860 0 4397 689 05:14:02
WLAN 11M/54M 1568 0 0 27 0 05:13:59


ADSL Link Downstream Upstream
Connection Speed 7168 kbps 448 kbps
Line Attenuation 15.5 db 27.0 db
Noise Margin 4.9 db 17.0 db

So, attenuation is back up and noise margin is down. Coudln't get to the line in time to listen with a phone.

Its worse than that as your line rate has dropped also.
I expect all this up and down rate change is playing havoc with your IP profile

Just after posting that (with line noise margin still down at 4.9) I took the router out of the phone test socket and put the phone in - clear noise on the line when I picked up, which went after a couple of seconds. Nothing else on the line except single phone.

Swapped back, router came back up with ...

System Up Time 05:17:56
Port Status TxPkts RxPkts Collisions Tx B/s Rx B/s Up Time
WAN PPPoA 86 83 0 280 484 00:01:32
LAN 10M/100M 94254 73577 0 4364 687 05:17:54
WLAN 11M/54M 1574 0 0 27 0 05:17:51


ADSL Link Downstream Upstream
Connection Speed 8128 kbps 448 kbps
Line Attenuation 10.0 db 6.0 db
Noise Margin 6.9 db 24.0 db

So - back up to 8128, with attentuation down to 10 and noise margin back to 7.

Anyone think I'll get charged by BT ?

Oh - and speed test now shows 3.3.

What's an IP Profile ?

Noise margin just dropped to 2.5, then steadied at 3.7. Speed test showed 0.7 !!!

After a smooth morning I was thinking of cancelling BT, but will let him come and see what happens on Thursday. With this evidence it seems clear there is a line noise problem.

Are you running Routserstats? That will log the noise/attenuation for you (and graph it), which, together with copies of your router log, should help you demonstrate the issue to the BT engineer.

Thanks - was just thinking of writing one