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High SINR - BT Open Reach still haven't resolved

frank121
Dabbler
Posts: 10
Registered: ‎23-09-2015

High SINR - BT Open Reach still haven't resolved

Hello,

About 2 months ago, I noticed that my synch speed had dropped from around 4500kbps - 5000kpbs to around 3000kpbs. After checking my router stats, I saw that the target SINR was hovering around 11 to 13dB when it's normally around 6dB.

I reported the fault to plusnet and they manually adjusted the SINR back to 6dB but over the course of around 7 days it dropped back to approx 12dB. This was done on two separate occasions. After the 2nd manual adjustment, Plusnet informed me that my line had failed the copper line test (high resistance failure) and an engineer was needed.

I had three visits because each time the problem wasn't fixed:

 

1st Engineer - Spent 4-5 hours outside and cleared the high resistance fault. After he left, the internet was almost unusable as the router kept dropping out at the target SINR of 6db.

 

2nd Engineer -  He spent about 2 hours inside the property. He capped my upload speed to 448kbps and set a target SINR of 7db. He didn't tell me that he had done this and when I noticed I asked plus net to remove the cap. After the change was made..the internet was unusable again.  (frequent drop out's and poor speed)

 

3rd Engineer - Spent about an hour inside the property. He changed the my ADSL faceplate for the new Interstitial one and re-capped the upload back to 448 and manually adjusted my SINR to 10. (even if I told him specifically to not limit my line again!) He said my line had a lot of interference and there was nothing he could do!

 

My question is, do BT open reach have a responsibility to get the SINR to a good level so that the line synchs at the correct speed? Is it acceptable for them to artificially restrict the line rather than locate and fix the issue?

Like I said at the beginning of this post, I had no such issues with SINR before a few months ago and the same issue is present directly in the test socket.

 

I have attached the stats taken just now. The fault ticket is still open with plusnet.

 

Thanks very much for any suggestions.

Frank

 

For background. I tested the router directly in the test socket for some days and the observation was the same.  Originally I had an adsl v1 faceplate and the ADSL is carried on a separate pair to data extension upstairs. The rest of the extensions are therefore voice only. This was later changed by the 3rd engineer to the later interstitial version. (The ADSL is of course still on a separate pair to the data extension)

 

 

 

 

 

Tags (1)
9 REPLIES
Superuser
Superuser
Posts: 13,048
Thanks: 4,341
Fixes: 26
Registered: ‎22-08-2007

Re: High SINR - BT Open Reach still haven't resolved

Hi Frank,

SNRM changes in the presence (or absence) of electrical noise.  It is not a fixed value.  Lines have a TARGET SNRM which they will seek to attain when first synchronising.  Targets are in multiples of 3dB, 6dB being the norm and anything higher is seeking to manage an unstable line.  I am therefore surprised by the suggested targets set by the BT engineers.

You first need to under take some basic self help checks...

Please perform a quiet line test - dial 17070 select option 2 using a corded phone plugged into the test socket behind the face plate of the master socket. It should be silent. A noisy phone line (or no dial tone) will have a marked adverse impact on the performance of broadband.

If the line is noisy or there is no dial tone, then a PHONE LINE fault needs to be raised with your phone provider. If this is PlusNet, you can report a fault on line using the button below.

 

Is the router plugged direct into the master socket?  Are there any phone extensions?

Take a look over the speed issues thread - see link below.

frank121
Dabbler
Posts: 10
Registered: ‎23-09-2015

Re: High SINR - BT Open Reach still haven't resolved

Hello Townman,

 

Thanks for your helpful post, I have read your replies in other threads which are always very useful. Prior to posting, I have been through the speed test post and also tried my router directly in the master socket. There seems to be little difference between the master socket and the "filtered" adsl extension which is connected to the interstitial master socket faceplate .

I have called 17070 a number of times and I can't hear any noticeable noise on the line. The line is also frequently used for voice calls and no one has complained over a noisy line. 

 

At the moment the SNR target has decreased to around 10db but I have no idea if this is just temporary.

A fault is already opened with plusnet and they are due to phone me again tomorrow.  Plusnet always seem to be very helpfull, but I unfortunately that;s not the case with BT open reach. What I really wanted to know is whenever BT OR should try and bring the target SINR in line or can simply fob me off saying my line is within tolerance blah blah.

Thanks for the interest.

Frank

 

 

 

 

System uptime:
25:55:31
Modem ADSL(Sync)uptime:
25:54:16
Interleaving:
On
ADSL mode:
ANNEX_A
ADSL2 PLUS
ADSL setting:
VPI:0
VCI:38
ADSL line speed:
Up:1160
Down:3150
Line attenuation:
Up:27.9
Down:48.6
SN margin:
Up:6.0
Down:10.0
Total errors seconds:
1809

 

 

Community Gaffer
Community Gaffer
Posts: 17,683
Thanks: 666
Fixes: 167
Registered: ‎05-04-2007

Re: High SINR - BT Open Reach still haven't resolved

 The line is looking much more stable over the last few days.
 
 Profile Info: WBC 160K - 24M Medium delay (INP 1) 12dB Downstream, UC Low delay (INP 0) 6dB Upstream (ADSL2+)
 
 
  Upstream DSL Link Information Downstream DSL Link Information
Loop Loss: 27.8 48.5
SNR Margin: 5.9 11.3
Errored Seconds: 6 0
HEC Errors: 0  
Cell Count: 3443 885
Speed: 1160 3150
 
Maximum Stable Rate (KBPS): 3424 Fault Threshold Rate (KBPS): 2739
Mean Time Between Retrains (Seconds): 21545 Mean Time Between Errors Upstream (Seconds): 265
Indicative Line Quality: R Mean Time Between Errors Downstream (Seconds): 3

 

The mean time between errors and line quality is very low, that needs resolving before we can really even think about lowering the SNR again. If you reply to the fault ticket advising that the speeds are still lower than expected, we can continue investigating.

If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff
frank121
Dabbler
Posts: 10
Registered: ‎23-09-2015

Re: High SINR - BT Open Reach still haven't resolved

Thanks for looking into this Chris, I will update the ticket.

Gel
Seasoned Pro
Posts: 1,665
Thanks: 168
Fixes: 14
Registered: ‎02-08-2007

Re: High SINR - BT Open Reach still haven't resolved

As a matter of interest are there reasons why 1 of my SNR's isn't in multiples of "3"?

. Board version: Plusnet Hub One
5. DSL uptime: 7 days, 20:47:31
6. Data rate: 902 / 2779
7. Maximum data rate: 902 / 2692
8. Noise margin: 6.0 / 5.4
9. Line attenuation: 36.7 / 63.2
10. Signal attenuation: 36.7 / 58.2
11. Data sent/received: 945.5 MB / 17.0 GB
Community Gaffer
Community Gaffer
Posts: 17,683
Thanks: 666
Fixes: 167
Registered: ‎05-04-2007

Re: High SINR - BT Open Reach still haven't resolved

The target SNR is multiples of 3, but the actual SNR will fluctuate slightly.

If this post resolved your issue please click the 'This fixed my problem' button
 Chris Parr
 Plusnet Staff
Superuser
Superuser
Posts: 13,048
Thanks: 4,341
Fixes: 26
Registered: ‎22-08-2007

Re: High SINR - BT Open Reach still haven't resolved

@frank121,

This looks grim!  The VR plait posted by Chris us not pretty.  Do you switch the router off when not using it or do you leave it switched on?

In the current context a falling SNRM is not good news - it indicates an increase in noise.

Your reference to a filtered ADSL extension from the interstitial face plate rather confused me.  Can you be clearer about this please?  ADSL extensions are not generally good news and (electrically) the ADSL connection is not filtered, the filtering applies to the phone connection.

Which faceplate have you got?  A photo would be helpful please.

Are you able to remove the lower faceplate and the built in filter to expose the test socket and connect to that using a 'dangly' filter please?  If yes can you please do that and post the stats, ideally leaving it connected in that manner for as long as possible.

frank121
Dabbler
Posts: 10
Registered: ‎23-09-2015

Re: High SINR - BT Open Reach still haven't resolved

Hello Townman,

 

The router is always turned on and has only been unplugged for testing at the master socket. The disconnections shown on the graph were being caused after BT left the property and the internet was unusable. (frequent drops and slow speed) This is now stable since their last visit but the synch speed is much lower than expected.

I have MK3 faceplate which was fitted by engineer number 3. I have a separate pair feeding the ADSL extension upstairs so voice and ADSL are on seperate pairs. (pic of master socket attached)

 

Last weekend, I tested the router directly in the "unfiltered" test socket with a separate dangly micro-filter and also in the dedicated ADSL socket on the top of master socket. I left it connected for about 24 hours but the SINR remained around 10-12db and it actually seemed better on the ADSL extension. I am not sure if it needed a longer time to indicate the true SINR and whenever the exchange has already marked my line as bad with a target SINR of 12db therefore it won't attempt to lower it anymore? Sad

 

Thank for the help.

Frank

 

 

 

 

 

 

 

 

frank121
Dabbler
Posts: 10
Registered: ‎23-09-2015

Re: High SINR - BT Open Reach still haven't resolved

Hi Chris,

 

Any chance you could speak to the plus net support team? It's really annoying not being able to speak to the same person because every-time it's a different story. Sad

 

Received this today, I have no idea where 9Mbps has come from. In the interim another rep has changed my SNR to 6db and it's unstable again. I am at a loss here and no one can tell me if BT should ensure a good SNR of around 6db at the master socket?

 

Thanks,

Frank

 

Escalation Ref 1021619 Date Raised 14/5/16
No. of Engineers 3 Fault Type DCN
Escalation level Team Member Escalation contact Portal/Email

 

Internal Checks Quality Gates
Microfilter N/A NTE N
Test Socket N/A D-Side N
Router N/A E-Side N
Extensions N/A Dropwire N
Powerline Adapters N/A Lift & Shift N
REIN Investigation N TPM N
       
Previous Work actioned: Engineer advised max attainable line speed 4424kbps. Fault has been left open to monitor following engineer work to ensure no longer disconencting
Current Work to be actioned: Customer reporting issue due to speed, engineer has advised not possible to increase speed past 4.4mbps. Reset to 9mbps has not gone through. Placed reset to amend speed profile, advised customer of notes as shown by engineer and options for further action (sync speed below MGALS)