Just like to thank everyone for there input, appreciated.

I got a call from Sky last night but hung up after 10 minutes of the caller having no clue as to what he was doing. Running continous tests on the line because I told him the engineer hasn't reset the speed profile...

I really do not have the patience to speak to an overseas call centre who have no idea, running test after test and him saying 'your line looks good'. Obviously it looks good, it's just been repaired.

Thanks /all.

My line rate/sync won't budge from those below;


Line Rate - Upstream (Kbps):5428
Line Rate - Downstream (Kbps):7095

Current Line Stats (Fibre);

Connection Speed: 7095 kbps 5428 kbps
Line Attenuation: 25.6 dB 0.0 dB
Noise Margin : 22.9 dB 6.6 dB

Line Attenuation for the upload doesn't register on the Sky Hub, had a few of these routers and each one gives the same problem.

IIRC the 0dB upstream attenuation is a bug in the Broadcom chipset/firmware that just affects VDSL2. If you connect the hub to an ADSL connection it will show an upstream attenuation figure.

Having checked the line rate/sync today, no change from yesterday.

Line Rate - Upstream (Kbps):5274
Line Rate - Downstream (Kbps):7095

Actually, downstream is the same and upstream is a little lower.

Connection did re-sync at approx 0830 this morning, a couple of times. I thought this was done automatically to adjust line rate as the line was stable but no change.
What should I do?

Morning!

What exactly happens when your line profile is reset?

I'm a little confused... My sync rate has improved and this happened after I received a callback from Sky, they stated that they had to pass a message on to another dept. to arrange the profile reset. The problem I've noticed is that my line doesn't seem to be budging from this new sync rate. Normally the sync changes each night as it works out the max stable line rate, this doesn't seem to be happening and I have room on the nm to allow greater speeds. My Fibre Line never offered fantastic speeds due to length but it was more than what I'm getting now...


Connection Speed..............22400 kbps.........5383 kbps
Line Attenuation.................25.5 dB................0.0 dB
Noise Margin........................9.3 dB................5.5 dB

Thanks /all

What does the dslchecker estimate for your line? www.dslchecker.bt.com?

35 but before the fault occurred, my Fibre rate was 27 but the line doesn't seem to be adjusting and the snr has some room left to improve the speed...

Correction, . You are very confused.

Whether the line profile has been set via Sky we cannot be sure. But something has certainly happened.

However "Normally the sync changes each night as it works out the max stable line rate" is not normal on FTTC and there is no such thing as "max stable rate".

It could be that 22400kbps is the top of a band, or it could be your line still has wide SNRM variations between day and night times. You could try a single daytime re-sync to see if it improves.

Following that, as long as you aren't getting overnight reconnections just leave it alone now. It will take time and stability for the DLM to remove banding if it is still in place. For example - this post.

Thanks for that RobertoS, that has cleared up any confusion.

I have just completed a re-sync and everything remains the same, I'll leave it alone and see how things progress.

If there is no max stable line rate, what is the 10 day line training for, I thought this was to work out your max stable line rate?

Thanks again, appreciated.

It is, on ADSLx, except all it does is record the lowest sync in the ten days and from that calculate the Fault Threshold Rate. It doesn't do any searching around for the "highest stable" as we would understand it.

On FTTC, BT Wholesale connections BTW may record it in the same way, but it is nothing to do with line training.

See the Openreach SIN 498 Section 2.2.1. The "intervene" there means "apply banding", not the day-to-day stuff like interleaving, SNRM etc.

Edited by RobertoS (Tue 06-Sep-16 14:09:51)