Poor downstream sync

I am trying to help an elderly friend of the family, she is in her mid eighties, with her ADSL broadband.

Downstream is very poor (704 kbps), upstream is as expected (760 kbps), distance from the exchange by road is approx. 2km. More complete stats are shown below. The BT Wholesale checker shows an expected Downstream Range of 5.5 to 7.5 Mbps.

I have taken a Billion 8800NL round and managed to get a graph from DSLStats which seems to show very high attenuation at higher frequencies (not sure how to post an image to this forum).

She has had Openreach visit a few times in the past but they have not resolved the problem and she stopped progressing it due to a period in hospital.
They are due to visit again in a few days and I will be present.
I have checked the wiring in the house and it all seems in order to me.
The outside cables are all underground.

Does anybody know what sort of faults can cause this sort of issue?

DSL Mode: ADSL2

Line Attenuation (dB) D/U: 37.5 / 22.8
Conn. Speed (kbps) D/U: 704 / 760
SNR Margin (dB) D/U: 2.9 / 6.0
Power (dBm) D/U: 0.0 12.7
Interleave D/U: 1 / 1

Pete

Does her landline phone work? One wire of the pair disconnected between her and the exchange can cause very low broadband speeds, but is accompanied by a complete loss of phone service.

Edited by RobertoS (Thu 14-Jun-18 18:28:07)

No problems at all on her landline, she uses it most days to both make and receive calls.
A 17070 Quiet Line test is clear, no noise is heard.

Any alarms or other devices connected to the line that may not have a filter on them?

Do the stats improve when using the test socket at all? And you've verified all extensions stop working when the test socket is exposed

No alarms or devices connected the line, there was an extension star wired before the master socket, I have disconnected the extension.

The master socket is quite old, no test socket.
I have unscrewed it and disconnected the one remaining extension and plugged the router directly in using a new cable and filter and also with no filter, it made no difference to the sync speeds.

When you disconnected the star-wired extension, did you disconnect it at the point of branching off, or at the user end of it? I expect you did it at the branch but I'm double-checking .

I disconnected the star wired extension where it branched off at the join between the incoming external black cable and the internal white cable going to the master socket..

Sync might have been banded and not change, so the impact on all the figures is what needs to be looked at

Banded sync would have a telltale high SNR though.

Why have none of these Openreach visits resulted in the LJU being replaced with an NTE ? This is bread and butter stuff for an SFI visit ....

Are the CP not raising SFI tasks ?

I was surprised to find an LJU. I am trying to discover more about the history of the problem, it seems to have been going on for at least six months and possibly many more.

Hence why asking what all the figures are when using the test socket, i.e. if noise margin is better compared to usual it tells us they are banded and that is wiring is improved and banding removed things will improve

I'm assuming the figures were taken after the remedial work but that is an assumption and OP needs to confirm.

Figures from the master socket, there is no test socket, with the extension wiring removed.
Only very minor changes compared with the figures from the extension

DSL Mode: ADSL2

Line Attenuation (dB) D/U: 37.5 / 22.9
Conn. Speed (kbps) D/U: 698 / 763
SNR Margin (dB) D/U: 2.9 / 6.0
Power (dBm) D/U: 0.0 12.8
Interleave D/U: 1 / 1

Openreach have visited twice in the past, the owner is not sure what they did, and are due to visit again on Tue 19 Jun 2018.

Figures are after the star wired extension was removed.

Which provider?

If this is Sky then you may need to get them to reset their line profile system, which tends to band people and seems to use power back off i.e. you can get stuck at the slow sync speeds even when something has been fixed.

On BT Wholesale based (WBC) services the system should usually relent after a few weeks and give the speed back if it is at all possible, but usually if there is more speed available but banding is holding you back you will see spare noise margin.

The downstream attenuation suggests speeds of 8000 Kbps are possible.

One possibility is a quirk with the ADSL2 mode, is the modem to set AUTO DSL standard negotiation? It may be worth trying the different ADSL/ADSL2/ADSL2+ modes.

It is a BT Wholesale service, John Lewis Broadband which is Plusnet. I think she mentioned having a line reset when I visited in January. It made no difference.

The BT Wholesale checker shows an expected Downstream Range of 5.5 to 7.5 Mbps which is in agreement with the figure derived from the attenuation.

I will try forcing the ADSL mode when I next visit.

Photo showing graph from DSLstats

https://photos.app.goo.gl/1cY6A1ykGKLSR6qUA

SFI visit this afternoon (19 Jun 2018).
Cable is OK between the master socket in her house (no. 37) and to outside number 29.
There is a cable issue, possible HR fault, between number 29 and the cabinet. It has been passed back as an open fault and will, hopefully, be progressed tomorrow.

Tried ADSL/ADSL2/ADSL2+ modes, no significant difference.

Yeah, thought it wouldn't. There's a line fault there, and changing modulation won't fix it.

Me too but it filled some time while waiting for Openreach to arrive.

What kind of SFI bod doesn�t do UG ??

He did UG work, ran out of time to complete the job.

Ah, OK, so he has retained the job for today then hopefully.

Did not retain job: "ran out of time, would of retained job but am on loan and back to my local area tomorrow".
I am trying to find out when the fault will be worked on again so that I can attend.

Openreach have not turned up today. ISP said that I have to make another appointment.
OR are booked for Thu 21 Jun PM.

OR engineer turned up early and ran some tests before I arrived.
He identified a split pair and has moved the line to a spare pair.
Downstream sync is now excellent.

DSL mode: ADSL2+
Line attenuation (dB): D/U 40.0 23.1
Connection speed (kbps): D/U 7979 888
SNR margin (dB): D/U 6.0 11.9
Power (dBm): D/U 0.0 12.8

Many thanks to all those who offered advice.

No worries, the connection speed is great for the line attenuation.