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Noise margin

balbinot
Newbie
Posts: 4
Thanks: 2
Registered: 11-11-2017

Noise margin

9 - Noise margin: 5.9/3.0

10 - Line attenuation: 13.9/17.0

 

I got a very low noise margin and my ADSL connection keeps dropping when there is intense traffic. Nothing has changed indoors, same modem, same cables. 

It used to work perfectly for the last 1.5 years.

 

Could it be cables outside? How to check this? 

9 REPLIES
Superuser
Superuser
Posts: 10,016
Thanks: 1,549
Fixes: 19
Registered: 22-08-2007

Re: Noise margin

Hi,

A warm welcome to the forums.

The normal margin is 6dB but some lines work perfectly well at 3dB.  Might be best to cover some basics - take a look at the BB speed issues link below.

Broadband is not going to work well if the "phone" line is not working properly.

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.


 

How is your line performing?

Please post your router stats; for PN TG582n and 2704n routers use the buttons below, for other routers look at the Kitz link.

Also run a BT Wholesale speed test (ideally using an Ethernet wired PC with the WiFi turned off) then run the further diagnostics and post the results here. DO NOT REBOOT the router!

Also find your CURRENT SPEED (PlusNet line profile) from the PlusNet user portal - you will need to log in.


 

balbinot
Newbie
Posts: 4
Thanks: 2
Registered: 11-11-2017

Re: Noise margin

 

Sorry, I do not have a phone to do the line noise test. 

Here are the ADSL statistics from the link you provided. 

 

 

Mode: ADSL_2plus    
Traffic Type: ATM    
Status: Up    
Link Power State: L0    
 
  Downstream Upstream    
Line Coding(Trellis): On On    
SNR Margin (1 dB): 3.0 5.9    
Attenuation (1 dB): 17.0 13.9    
Output Power (1 dBm): 0.0 12.7    
Attainable Rate (Kbps): 15312 436    
 
  Path 0   Path 1  
  Downstream Upstream Downstream Upstream
Rate (Kbps): 15166 435 0 0
 
MSGc (# of bytes in overhead channel message): 54 13 0 0
B (# of bytes in Mux Data Frame): 254 12 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 2 4 0 0
R (# of check bytes in FEC Data Frame): 0 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.5369 0.9369 0.0 0.0
L (# of bits in PMD Data Frame): 3799 111 0 0
D (interleaver depth): 1 1 0 0
Delay (msec): 0 0 0.0 0.0
INP (DMT symbol): 0.00 0.00 0.0 0.0
 
Super Frames: 0 0 0 0
Super Frame Errors: 165472 31403 0 0
RS Words: 0 3530842 0 0
RS Correctable Errors: 0 0 0 0
RS Uncorrectable Errors: 0 0 0 0
 
HEC Errors: 1720699 9423 0 0
OCD Errors: 0 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 29604296 843294 0 0
Data Cells: 1240196 275796 0 0
Bit Errors: 0 120 0 0
 
Total ES: 9820 25352    
Total SES: 3417 12    
Total UAS: 16740 13885    

 

Superuser
Superuser
Posts: 10,016
Thanks: 1,549
Fixes: 19
Registered: 22-08-2007

Re: Noise margin

Something is odd here - a 17dB attenuated line ought to do far better than this - I suspect line noise.

A telephone hand set to be used as a diagnostic tool (if not for making calls) is an absolute essential.  If you cannot pick one up for around £5 (e.g. from Tescos) then can you borrow one?

balbinot
Newbie
Posts: 4
Thanks: 2
Registered: 11-11-2017

Re: Noise margin

I will try to get one from work tomorrow and do the test. Will report back soon.

 

Thanks!

Plusnet Help Team
Plusnet Help Team
Posts: 4,153
Thanks: 864
Fixes: 212
Registered: 21-04-2017

Re: Noise margin

Hi there.

I'm sorry to hear you're experiencing connection problems.


Testing your line is finding a potential fault at the exchange so I've reported that through to Openreach now. We've not received confirmation of the fault being accepted but we'll let you know when we know more via this ticket.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
Superuser
Superuser
Posts: 10,016
Thanks: 1,549
Fixes: 19
Registered: 22-08-2007

Re: Noise margin

Odd PPP session durations - they all look circa 2+ a bit hours or multiples there of...

Plusnet Help Team
Plusnet Help Team
Posts: 4,153
Thanks: 864
Fixes: 212
Registered: 21-04-2017

Re: Noise margin

The fault report is showing to be cleared at the cabinet.

 

Can you monitor your connection over the next couple of days and let us know if the problems return?

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team
balbinot
Newbie
Posts: 4
Thanks: 2
Registered: 11-11-2017

Re: Noise margin

First few hours of use and it seems to have improved. I will keep monitoring for a few days and report back.

Thanks for the help!

 

Here are the new stats

 

 

 
Mode: ADSL_2plus    
Traffic Type: ATM    
Status: Up    
Link Power State: L0    
 
  Downstream Upstream    
Line Coding(Trellis): On On    
SNR Margin (1 dB): 3.8 6.3    
Attenuation (1 dB): 9.0 3.6    
Output Power (1 dBm): 0.0 12.5    
Attainable Rate (Kbps): 23888 1252    
 
  Path 0   Path 1  
  Downstream Upstream Downstream Upstream
Rate (Kbps): 24172 1251 0 0
 
MSGc (# of bytes in overhead channel message): 58 12 0 0
B (# of bytes in Mux Data Frame): 254 38 0 0
M (# of Mux Data Frames in FEC Data Frame): 1 1 0 0
T (Mux Data Frames over sync bytes): 3 4 0 0
R (# of check bytes in FEC Data Frame): 0 0 0 0
S (ratio of FEC over PMD Data Frame length): 0.3371 0.9904 0.0 0.0
L (# of bits in PMD Data Frame): 6051 315 0 0
D (interleaver depth): 1 1 0 0
Delay (msec): 0 0 0.0 0.0
INP (DMT symbol): 0.00 0.00 0.0 0.0
 
Super Frames: 0 0 0 0
Super Frame Errors: 21372 3007 0 0
RS Words: 0 1254230 0 0
RS Correctable Errors: 0 0 0 0
RS Uncorrectable Errors: 0 0 0 0
 
HEC Errors: 149175 1333 0 0
OCD Errors: 0 0 0 0
LCD Errors: 0 0 0 0
Total Cells: 259980103 13430181 0 0
Data Cells: 185210735 8375448 0 0
Bit Errors: 0 0 0 0
 
Total ES: 958 1684    
Total SES: 458 6    
Total UAS: 3617 3196    

 

Plusnet Help Team
Plusnet Help Team
Posts: 4,153
Thanks: 864
Fixes: 212
Registered: 21-04-2017

Re: Noise margin

Happy to hear that!

Keep us posted.

If this post resolved your issue please click the 'This fixed my problem' button
 Anoush Mortazavi
 Plusnet Help Team