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line noise margins @ 8128kbps

sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

Thanks James, will try that later on today and post back. been working all night and i need to get some sleep.

PS why does it only happen when i sync at 8128 and not at slower syncs? If it was a BT wholesale problem wouldnt it be happening across the range of syncs?
16 REPLIES
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

I am currently experiencing line noise problems when my router is synced at 8128kbps.
@ 8128kbps the router syncs with a line noise margin of around 9db. When the phone is used the margin drops to below 0db and loses sync.
BT BRAS then drops the sync speed (currently at 5684kbps) when the phone is used at this sync there is no alteration in line noise margin (currently at 17db).
After a couple of days BRAS then increases my speed back to 8128 kbps and the problems come back.
I have tried changing phones, line filters, plugging line filters straight into the master socket. As I only have one phone and no sky there is nothing else plugged in.
I have raised a ticket (ID: 22081396) and PN tell me BT fault finding service doesnt find any faults. If BT are called out they will charge £144 +vat if no fault is found. I have been stung before for the £85 before by BT and was wondering if anyone on here had any advise.
Also, when PN used BT's fault finding service, if i was synced at the lower speed when the service was run would it of found a fault?

PS please bring back James (hes a guru) Bailey.
Community Veteran
Posts: 1,160
Thanks: 1
Registered: 01-08-2007

line noise margins @ 8128kbps

Can't help you myself (doing similar testing at the moment and coming to the conclusion that I need to fit a filtered faceplate) but it appears your wish was granted yesterday!

See:
http://portal.plus.net/central/forums/viewtopic.php?t=56842
Plusnet user since November 2003
Currently on Unlimited Fibre Extra and Unlimited UK & Mobile Calls
James
Grafter
Posts: 21,036
Registered: 04-04-2007

line noise margins @ 8128kbps

Hi dcstechnologies,

It's really quite ironic that you should say that, given that I moved back to the Comms Team yesterday Smiley

I can see you've done quite a bit of work to ensure that the problem isn't one being caused by your equipment, which is great, but can I ask you to try one more thing? Can you try unscrewing the faceplate from your master socket, take your microfiler and plug this directly into the test socket on the bottom half. Plug your router into the ADSL side and your telephone into, bizarrely enough, the phone side of the filter.

Then if you keep an eye on your routers sync rates, try connecting to the internet and then picking up your phone again. If you are still seeing sync variations then this would point towards a BT Wholesale related fault. However, if you not see sync variations, then this would point towards a fault on your master socket, which is BT Retails responsibility to fix.

The SFI Engineer charge of £144+VAT would apply if it were a fault caused by your router, filter or internal wiring, which you have just about ruled out, so I wouldn't worry about it too much once you have run the test socket test as I outlined above.
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

Already had a NTE with microfilter face plate fitted when BT came last year and charged me £85!

Thanks for the heads up about james,
James
Grafter
Posts: 21,036
Registered: 04-04-2007

line noise margins @ 8128kbps

Hi again,

I'm going to have to go with coincidence. there shouldn't be any issues with a noise margin of 9dB. That's 3dB higher than the standard max profile, which should mean that you should see a more stable connection than most!

Go with the test socket thing once you've had a bit of sleep and we'll see how you get on.
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

i will have to wait till BRAS resyncs me to 8128kbps as its fine at slower syncs. Im on 5984 kbps at the mo. please have a look at the ticket for a full explaination of whats been going on.

ticket ID: 22081396
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

Thanks for your help James, seems to have sorted itself out. syncing @ 8128kbps now and LNR doesnt drop when the phone is used.
Great to see ya back with the 'living' tho m8.
James
Grafter
Posts: 21,036
Registered: 04-04-2007

line noise margins @ 8128kbps

That's great news. Hope it stays that way Smiley
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

james im not complaining but have a look at this


10069!
N/A

line noise margins @ 8128kbps

Hi dcstechnologies

I have a similar problem (on the face of it) - every time the phone is used I drop 6db or so, current my SNR target is set at 12 so I'm stable, but at a lower sync rate than my line is capable of at a 6db SNR Target.

I've tried new filters, cabling, disconnecting everything else etc. including stripping out an unused extension - no joy.

Can you advise if a change was actually made to fix your problem, or did it just dissappear ?

Thanks
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

it lasted for about two weeks,
it started with line noise when i was using the phone, then that disappeared and the sync drops started coming when the phone was in use.
then the problem disappeared today.
what router do you use?
Have a look here, this may help.
http://www.kitz.co.uk/adsl/lowSNR.htm
N/A

line noise margins @ 8128kbps

Spookily similar.

I had audible noise on the voice line (that only the other end could hear), then it bled through to our end. Had BT out but they couldn't find anything. The audible noise problem seems to have dissappeared, but the adsl line-noise when phoning persists.

I'm on a DG834G, which is amazing at holding on. I've seen negative 3db SNR Margin and it still doesn't lose synch, however it's dropped synch enough that the target has been raised to 12db, so even though I drop 6db when the phone's in use I still have a 6db margin and I don't lose synch. I'm just missing out on about 2M of speed, since the 12db Target pulls my synch speed down.

Already removed the ring-wire, checked everything internal, had BT out (couldn't find anything) so I was hoping James (MrFixIt) Bailey had performed some magic that he could repeat on my line.

Thanks anyway - faint hopes, dashed once more - I'm in a high-RF region with a fairly long line, synching at 3776 so guess I should be happy to have anything at all.

Like your speedtest though.....
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

i'm on the similar router (dg834gt), there is a way to override to target SNR, but it only last till you reboot the router.

DG834GT - How to Overide Target SNR on the DSLAM

~ Enable debug via the web interface
http://192.168.0.1/setup.cgi?todo=debug

~ Then telnet the router

~ when logged in type the following command
/usr/sbin/adslctl configure --snr N

where N = (target SNR * 16)

havent tried it myself, maybe James has a comment about this script.
sloany
Grafter
Posts: 153
Registered: 08-06-2007

line noise margins @ 8128kbps

another tool which maybe of use to you

http://www.vwlowen.co.uk/internet/files.htm