Noise on quiet line test (listen to recording)

This evening I noticed my SN margin dropped to 0.2 db with an increase in CRC errors and attainable rate went down to ~20Mbps from ~40Mbps.

I did a quiet line test on 17070 and this is how my line sounds:
http://www.4shared.com/mp3/e3E74CTYba/BT_Quiet_Line_...

Previously my line was devoid of such noises.

Have already reported this as a fault.

Any ideas what could be causing this?

Seems to be related to my sync speed dropping by ~10Mbps previously: http://forums.thinkbroadband.com/fibre/t/4441199-ftt...

EDIT: Also noticed that the SN margin drops whilst the phone line is in use (which did not occur before)

Edited by deleted (Tue 08-Mar-16 08:37:46)

Any ideas what could be causing this?

Yes, a poor connection between you and the cabinet somewhere.

I managed to schedule a BT engineer to come in the next few days to do some checks but concerned I may be charged £130.

Anything I should tell the engineer? Perhaps he can move me onto a better port in the FTTC cabinet?

I did some tests:
SN margin drops to nearly 0.5 db from 6db (as reported by the HG612 modem) when:
-Landline is called (without any telephones connected)
-Landine is called (with telephones connected)
-Landline is picked up

Surely this suggests a problem somewhere between the master socket and cabinet somewhere and not on my premises?

Is the noise still there if you turn off your modem/router and take it/their plugs out of the mains socket? Note - removing the power cord from the device instead is a waste of time.

In reply to a post by RobertoS:

Is the noise still there if you turn off your modem/router and take it/their plugs out of the mains socket? Note - removing the power cord from the device instead is a waste of time.

Yes still there, as it sounds in the recording.

My main concern really is the FTTC side of things, even when there aren't any telephones connected to the master socket, just the RJ11 cable, if I call the landline, the SN margin still drops (as reported by the HG612 modem). Very strange.

Edited by deleted (Wed 09-Mar-16 13:09:34)

Bob just asked the best question ... is the sound still present at the NTE with all else, including extension wiring, disconnected. You have answered yes to this, so that's good.

Did you report this as a noisy line fault or for the FTTC part ?

If as a noisy line, then don't be bothering the engineer with the whole SNR dipping thing .... they very likely won't be interested. Show a little interest yourself in the tests they run, ask if they don't mind you watching, if possible ask them to explain the results of the PQ (pair quality) test they run .... what you are looking for is a nice high AC balance, preferably over 60db (though the machine will pass it at 55db or over) and most importantly that both legs should be nice and balanced, ideally less than 3 nanofarad's difference between the two readings. The TDR function on their tester should be used to try and look for an HR ... also a good long listen to the quiet line test if the noise isn't immediately apparent.

If the engineers visit has been raised to look at the FTTC side of things, maybe an SFVA or a BOOST task, then feel free to mention the SNR thing, they should be able to duplicate this with their tester in manual sync mode and watching the error counter and snr whilst they use the phone at the same time.

In reply to a post by Zarjaz:

Bob just asked the best question ... is the sound still present at the NTE with all else, including extension wiring, disconnected. You have answered yes to this, so that's good.

Did you report this as a noisy line fault or for the FTTC part ?

If as a noisy line, then don't be bothering the engineer with the whole SNR dipping thing .... they very likely won't be interested. Show a little interest yourself in the tests they run, ask if they don't mind you watching, if possible ask them to explain the results of the PQ (pair quality) test they run .... what you are looking for is a nice high AC balance, preferably over 60db (though the machine will pass it at 55db or over) and most importantly that both legs should be nice and balanced, ideally less than 3 nanofarad's difference between the two readings. The TDR function on their tester should be used to try and look for an HR ... also a good long listen to the quiet line test if the noise isn't immediately apparent.

If the engineers visit has been raised to look at the FTTC side of things, maybe an SFVA or a BOOST task, then feel free to mention the SNR thing, they should be able to duplicate this with their tester in manual sync mode and watching the error counter and snr whilst they use the phone at the same time.

I reported two faults, initially for the phone line and later for broadband. It seems the BT support guy who rang me earlier scheduled the engineer visit under phone fault, from what I can see in my account. So if it's a phone fault engineer I'll just let him do his thing.

Cheers

Edited by deleted (Wed 09-Mar-16 13:36:55)

So if it's a phone fault engineer I'll just let him do his thing.

No, there's a lot of new boys on the park who have had the 'charge and be damned' school of thought drummed in to them.

Show a little interest yourself in the tests they run, ask if they don't mind you watching, if possible ask them to explain the results of the PQ (pair quality) test they run .... what you are looking for is a nice high AC balance, preferably over 60db (though the machine will pass it at 55db or over) and most importantly that both legs should be nice and balanced, ideally less than 3 nanofarad's difference between the two readings. The TDR function on their tester should be used to try and look for an HR ... also a good long listen to the quiet line test if the noise isn't immediately apparent.

Follow that advice.

Good luck.

Will do.

I've been reading about high resistance faults, perhaps this could be why the SN margin drops when my landline is called (even without any telephones connected). This is the first time I've seen this behaviour occur on my line. Anything else which could cause this?

Anything else which could cause this?

A duff filter at the customers end, and very rarely (and not applicable to you as you have FTTC) an issue with the PSTN equipment in the exchange.

In reply to a post by Zarjaz:

Anything else which could cause this?

A duff filter at the customers end, and very rarely (and not applicable to you as you have FTTC) an issue with the PSTN equipment in the exchange.

I have this SSFP Infinity faceplate which was installed by an engineer (seemed to be a contractor) when I first got FTTC in 2013. http://bt.custhelp.com/rnt/rnw/img/enduser/ssfp_sock...

Anything else which could go wrong with the FTTC cabinet itself?

Edited by deleted (Wed 09-Mar-16 14:16:31)

Anything else which could go wrong with the FTTC cabinet itself?

There's filters in there too, and although saying I've not come across it doesn't mean it doesn't exist ....

Stick with the HR theory as the most likely cause.

In reply to a post by Zarjaz:

Anything else which could go wrong with the FTTC cabinet itself?

There's filters in there too, and although saying I've not come across it doesn't mean it doesn't exist ....

Stick with the HR theory as the most likely cause.

Thanks, I'll see how this goes.

Some graphs anyway:
https://bt.i.lithium.com/t5/image/serverpage/image-i...
https://bt.i.lithium.com/t5/image/serverpage/image-i...
https://bt.i.lithium.com/t5/image/serverpage/image-i...
https://bt.i.lithium.com/t5/image/serverpage/image-i...

Edited by deleted (Wed 09-Mar-16 15:13:46)

BT engineer came and he connected a testing device to the test socket. Results came back good, so he found nothing wrong. He then said he would go to the exchange and check the line cards and call back later. Shouldn't he be checking the FTTC cabinet?

The SN margin still drops when the phone line is in use or called.

Edited by deleted (Fri 11-Mar-16 15:57:15)

If you plug a corded phone into the Test Socket is it noisy?

Hopefully it is - get him to listen to that and see what he says...

In reply to a post by b4dger:

If you plug a corded phone into the Test Socket is it noisy?

Hopefully it is - get him to listen to that and see what he says...

He didn't bother to listen to the phone, just plugged in his test device to the test tocket and ran some tests which were "OK".

He said he suspects a faulty line card which may need to be replaced. Does this make sense, I thought it was fibre optic from the exchange to the FTTC cabinet and then copper from the FTTC cabinet to my premises.

Edited by deleted (Fri 11-Mar-16 16:11:37)

He didn't bother to listen to the phone, just plugged in his test device to the test tocket and ran some tests which were "OK".

Utter [censored]. How can a CP/customer report a line as 'noisy' and the engineer not even listen to the line ???

Ring your CP and complain.

In reply to a post by Zarjaz:

He didn't bother to listen to the phone, just plugged in his test device to the test tocket and ran some tests which were "OK".

Utter [censored]. How can a CP/customer report a line as 'noisy' and the engineer not even listen to the line ???

Ring your CP and complain.

I think I'll reopen the fault. Well I did ask if he was going to charge and he said no since he didn't actually fix anything and couldn't find the fault at my end.

Well I did ask if he was going to charge and he said no since he didn't actually fix anything and couldn't find the fault at my end.

That's the very definition of 'right when tested' ..... which I would strongly suspect would see the engineer being prompted to raise charges when he closed the task. Ask your CP when you speak to them.

In reply to a post by Zarjaz:

Well I did ask if he was going to charge and he said no since he didn't actually fix anything and couldn't find the fault at my end.

That's the very definition of 'right when tested' ..... which I would strongly suspect would see the engineer being prompted to raise charges when he closed the task. Ask your CP when you speak to them.

I have another engineer visit booked for next week. Anything else I should demonstrate this time?

What I am concerned about is the next engineer might just run the same test again. As in connect his test device to the NTE5 test socket with no telephone connected and the test will pass of course.

It seems when the modem is connected, the noise margin dropping/losing sync during phone calls is apparent. How do I get the engineer to see this??? Last engineer wasn't really interested in my graph stats. Tried another modem/router, RJ11 cables, filters, etc, to no avail.

In reply to a post by Zarjaz:

Bob just asked the best question ... is the sound still present at the NTE with all else, including extension wiring, disconnected. You have answered yes to this, so that's good.

Did you report this as a noisy line fault or for the FTTC part ?

If as a noisy line, then don't be bothering the engineer with the whole SNR dipping thing .... they very likely won't be interested. Show a little interest yourself in the tests they run, ask if they don't mind you watching, if possible ask them to explain the results of the PQ (pair quality) test they run .... what you are looking for is a nice high AC balance, preferably over 60db (though the machine will pass it at 55db or over) and most importantly that both legs should be nice and balanced, ideally less than 3 nanofarad's difference between the two readings. The TDR function on their tester should be used to try and look for an HR ... also a good long listen to the quiet line test if the noise isn't immediately apparent.

If the engineers visit has been raised to look at the FTTC side of things, maybe an SFVA or a BOOST task, then feel free to mention the SNR thing, they should be able to duplicate this with their tester in manual sync mode and watching the error counter and snr whilst they use the phone at the same time.

How do I get the engineer to see this???

I'd suggest concentrating on getting the noisy line fixed and only move on to other things if, once the noisy line is no more, you are still seeing broadband related issues.

I have another engineer visit booked for next week. Anything else I should demonstrate this time?

Yes, ask them to connect their butt (test phone) to the line and listen to a quiet line test, maybe even with it on speaker so you can listen as well.

In reply to a post by Zarjaz:

I have another engineer visit booked for next week. Anything else I should demonstrate this time?

Yes, ask them to connect their butt (test phone) to the line and listen to a quiet line test, maybe even with it on speaker so you can listen as well.

One thing I noticed but I'm uncertain if this was the case previously, it seems there is no noise when the VDSL2 modem is not connected to the phone line?

When the VDSL2 modem is on the hook, that's when I can hear some static noise as if the broadband signal is leaking onto the voice part. Tested another modem/router, still noise.

Edited by deleted (Sat 12-Mar-16 17:12:55)

That's not what you said in this post.

In reply to a post by RobertoS:

That's not what you said in this post.

I know, it seems to be intermittent, I listened again just now, unplugged the modem (power plug + RJ11 cable), the noise is still there. Seems to be worse at different times of the day.

Really frustrating not knowing what this is exactly.

Edited by deleted (Sat 12-Mar-16 17:36:32)

What else in the house is connected to the phone line? Sky boxes and burglar alarms are the common ones, and people nearly always forget about burglar alarms.

In reply to a post by RobertoS:

What else in the house is connected to the phone line? Sky boxes and burglar alarms are the common ones, and people nearly always forget about burglar alarms.

No sky boxes or burglar alarms. Just the telephone and modem are connected to the phone line.

I think this time it would be best if I let the engineer hear the noise on the phone line first hand, I can't believe he didn't even listen, he relied solely on his test device. As I tried to push him to do more he said he can't due to 'protocol' or else he would be scolded at. He did mention that 2 customers at the exchange had their line cards removed, not sure if that has any bearing. Overall he was friendly though.

Edited by deleted (Sat 12-Mar-16 17:54:25)

Did you report it as an audible noise fault on the phone, or as a broadband fault? Are the phone and broadband with the same ISP?

In reply to a post by RobertoS:

Did you report it as an audible noise fault on the phone, or as a broadband fault? Are the phone and broadband with the same ISP?

Yes I reported it as noise on the line and that picking up the phone/receiving calls affected the VDSL2 signal (sn margin drops/sync is sometimes lost), so it's under phone fault. I asked for a broadband engineer but the support agent gave a sarcastic reply.

Yes phone and broadband same ISP.

I'm out of contract anyway (except line rental saver) so if this isn't resolved I'll probably switch to VM.

Edited by deleted (Sat 12-Mar-16 17:57:56)

Someone from BT rang earlier to discuss the issue and confirm the next engineer visit.

Good timing he heard the actual noise on the line and the modem lost sync.

Fingers crossed!

The engineer called you might not be him in next visit. So, beware of it!

In reply to a post by adslmax:

The engineer called you might not be him in next visit. So, beware of it!

I think I prefer a different engineer this time around.

Fingers crossed!

Received two emails, first saying the engineer is at my property and then a few minutes later saying the job was done. I can't be sure if the engineer really did something since he never made contact.

The issue still persists, SN margin drops when there is a load on the line (as in the phone is picked up or call received). I did notice though that from the QLN graphs the noise has decreased in the lower tones and attainable max rate has increased.

Went on live chat and confirmed that the engineer did check the cabinet but could not detect noise. I finally pushed for this to be classed as a possible "high resistance" fault.

Anyway 3rd engineer visit in 48 hours...

Fingers crossed

Edited by deleted (Wed 16-Mar-16 15:49:50)

3 engineer callouts so far and still the issue remains...

4th next...

4th engineer came and he did a much better job this time than the first three engineers.

He discovered a 'HR dis' fault and used an 87J oscillator. He really did the best he could but couldn't access one of the boxes upstairs to check further (needs a key from the landlord but main office closed today)

Fingers crossed.

Took 8 engineers visits to sort my line fault, only No8 finally sorted the problems, did take him 2 days work though.

Edited by Nightglow (Thu 24-Mar-16 13:45:07)

Blimey that's a lot.

5th engineer visit now booked.

Edited by deleted (Thu 24-Mar-16 15:10:58)

G.INP now enabled, connected to an ECI cabinet.

G.INP Framing: 18 0
G.INP lookback: 31 0
RRC bits: 0 24
Bearer 1

Still waiting for the engineer to arrive though.

Edited by deleted (Wed 30-Mar-16 17:59:54)

I gather from the earlier parts of the thread you are probably on BT Infinity. If so, or any other BT Wholesale connection, please could you run this BTW diagnostic test and report back to us the downstream IP Profile, and your sync speed reported by your router?

This is just to help some of us settle a discussion about G.INP and ECI cabinets.

In reply to a post by RobertoS:

I gather from the earlier parts of the thread you are probably on BT Infinity. If so, or any other BT Wholesale connection, please could you run this BTW diagnostic test and report back to us the downstream IP Profile, and your sync speed reported by your router?

This is just to help some of us settle a discussion about G.INP and ECI cabinets.

Download speedachieved during the test was - 35.56 Mbps
For your connection, the acceptable range of speedsis 40 Mbps-37.05 Mbps .
Additional Information:
IP Profile for your line is - 37.05 Mbps

Stats recorded 30 Mar 2016 11:50:48

DSLAM/MSAN type: IFTN:0xb204 / v0xb204
Modem/router firmware: AnnexA version - A2pv6C038m.d24j
DSL mode: VDSL2 Profile 17a
Status: Showtime
Uptime: 57 min 29 sec
Resyncs: 0 (since 30 Mar 2016 11:36:15)

Downstream Upstream
Line attenuation (dB): 21.4 0.0
Signal attenuation (dB): Not monitored
Connection speed (kbps): 39999 9995
SNR margin (dB): 6.5 6.2
Power (dBm): 12.1 6.8
Interleave depth: 1 1
INP: 52.00 0
G.INP: Enabled Not enabled
Vectoring status: 5 (VECT_UNCONFIGURED)

RSCorr/RS (%): 0.0010 0.0000
RSUnCorr/RS (%): 0.0000 0.0000
ES/hour: 0 0

I'm supposed to be on up to 76 Mbps. Looks like I've been capped to 39999 Kbps?

Still having the same issue though, noise margin drops/lose sync when phone line in use/call received.

Having G.INP enabled on an ECI cab is a welcome surprise.

Thanks. But yuk for my purpose as they don't fit either of the theories. I see the stats were just after I asked fro them. Is the IP Profile from the same time, or something historic?

Re capped, it looks more like the actual Openreach product is 40/10, rather than 80/20 "banded". This can happen, but BT are likely to be seeing the 76/19 on your account if that's what was ordered. Have you ever had over 40Mbps real speed?

In reply to a post by RobertoS:

Thanks. But yuk for my purpose as they don't fit either of the theories. I see the stats were just after I asked fro them. Is the IP Profile from the same time, or something historic?

Re capped, it looks more like the actual Openreach product is 40/10, rather than 80/20 "banded". This can happen, but BT are likely to be seeing the 76/19 on your account if that's what was ordered. Have you ever had over 40Mbps real speed?

When I first got FTTC in 2013 I had sync rates of ~58 Mbps and real world speeds over 40 Mbps. The stats I posted are from today, including the IP profile.

5th engineer came, did some work for nearly 2 hours. The problem seems to have been fixed since my sn margin remains stable even if the phone line is in use/phone call received.

He said I had a bad line and I think he did a line swap. He wasn't really talkative or explained much so just let him do his work.

Cheers

EDIT: Engineer notes mentioned a fault at the node external to my property which was fixed.

Edited by deleted (Wed 30-Mar-16 15:10:54)

Fingers crossed. But you need to check which Openreach product it is some time.

In reply to a post by RobertoS:

Fingers crossed. But you need to check which Openreach product it is some time.

Yes I'm on the 76/19 package. I think due to the fault DLM capped my sync rate since the attainable rate is higher:

Max: Upstream rate = 9961 Kbps, Downstream rate = 48056 Kbps
Bearer: 0, Upstream rate = 9779 Kbps, Downstream rate = 39999 Kbps

It turns out the pair was changed from node to node and that the fault was located on the d-side. Seems to have fixed the problem!

Edited by deleted (Wed 30-Mar-16 17:29:52)

How very sad it has taken so long for you to get a 'decent' engineer out.

I might add that most are, but exceptional pressure from those above to comply to stats that are frankly awful causes even the most committed to struggle and do what is right.

In reply to a post by Zarjaz:

How very sad it has taken so long for you to get a 'decent' engineer out.

I might add that most are, but exceptional pressure from those above to comply to stats that are frankly awful causes even the most committed to struggle and do what is right.

Yes indeed. The guy seemed like he was having a bad day, didn't talk much, but at least he did a good job.

With those figures is it worth being on 76/19? If you moved to a 40/10 you would hardly notice the difference.

In reply to a post by MHC:

With those figures is it worth being on 76/19? If you moved to a 40/10 you would hardly notice the difference.

I was thinking about that but I would have to recontract for 12 months. I was thinking about switching to a cable provider such as VM instead if this issue wasn't solved.

If it has been banded it needs removing anyway, and if he has been moved onto 40/10 accidentally, which we have seen happen, things need sorting out.

Frontline support won't have a clue what that means .

Edited by RobertoS (Wed 30-Mar-16 18:46:34)

The way to tell is to check the Upstream IP Profile using this test

In reply to a post by smsmasters:

In reply to a post by RobertoS:

I gather from the earlier parts of the thread you are probably on BT Infinity. If so, or any other BT Wholesale connection, please could you run this BTW diagnostic test and report back to us the downstream IP Profile

Download speedachieved during the test was - 35.56 Mbps
For your connection, the acceptable range of speedsis 40 Mbps-37.05 Mbps .
Additional Information:
IP Profile for your line is - 37.05 Mbps

In reply to a post by RobertoS:

If it has been banded it needs removing anyway, and if he has been moved onto 40/10 accidentally, which we have seen happen, things need sorting out.

Frontline support won't have a clue what that means .

I was told by a support agent I would have to wait 24 hours for the line to stabilise after the line fault was cleared.

The upstream rate IP profile for my line is 20 Mbps so I assume I've just been banded on the downstream.

In reply to a post by smsmasters:

I was told by a support agent I would have to wait 24 hours for the line to stabilise after the line fault was cleared.

Probably rubbish, but it is possible a reset order on the DLM has been placed to remove the banding.

The upstream rate IP profile for my line is 20 Mbps so I assume I've just been banded on the downstream.

Yes. That is conclusive except on legacy Plusnet 40/20. My brain is very fuzzy at the moment or I would have suggested looking at that, as BatBoy did.

Do you think I could claim compensation for all this hassle?

EDIT: I'm told an engineer is supposedly being "sent to the exchange and cabinet to perform a DLM reset" and my compensation claim has been forwarded to a higher level team.

Edited by deleted (Thu 31-Mar-16 13:21:01)

Now my sync has dropped from 39999 to 34999 and now 32400 Kbps but the SN margin is 11.6.

Really fed up now, I think it's better I switch to another FTTC provider that uses the same OR network. Perhaps my DLM will be reset then.

Edited by deleted (Fri 08-Apr-16 13:23:33)

Resetting DLM will not resolve this. There's obviously still some issue existent if DLM feels the need to reduce the banded profile on your line.

Yes, I agree. The phone line fault needs fixing to allow stability.

In reply to a post by Zarjaz:

Yes, I agree. The phone line fault needs fixing to allow stability.

I think the pair swap did the trick, for now.

The noise margin does not seem to drop or lose sync when the phone line is in use.

I think it's still DLM banding my line since I still have spare downstream capacity?

Max: Upstream rate = 9879 Kbps, Downstream rate = 48556 Kbps
Bearer: 0, Upstream rate = 9682 Kbps, Downstream rate = 32400 Kbps
Bearer: 1, Upstream rate = 0 Kbps, Downstream rate = 0 Kbps
Link Power State: L0
Mode: VDSL2 Annex B
VDSL2 Profile: Profile 17a
TPS-TC: PTM Mode(0x0)
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 11.4 6.2
Attn(dB): 21.0 0.0
Pwr(dBm): 10.9 6.9

Edited by deleted (Sat 09-Apr-16 10:20:04)

Well just had a call from level 2 support

They won't do anything since my speed is within limits of 25 to 35 Mbps...

I think I'll have to move to cable.

Edited by deleted (Sat 09-Apr-16 12:06:26)

Had my DLM finally reset by a BT OR engineer.

All back to normal now.

Edited by deleted (Tue 19-Apr-16 15:34:15)