Could you post your downstream attenuation, snr and speed and say what make and model of router you are using.

Router: Netgear DG834G v4

Current sync 2912 Kbps

Downstream att. 57db (this has remained steady throughout
Noise Margin 6.3 db but goes up to sbout 7.6 at times.

I may ring support over the weekend and see if I can get them to send BT round (which I am prepared to pay for if necessary)

So (if I understand this correctly), because your sync speed is right on the border line of one of the DLM speed profiles, the DLM chops and changes your available speed by as much as half a megabit?

I'm not sure there's much you're going to be able to do about that, except move to an ISP that doesn't use BT back haul network (and hence no DLM).

If you can switch to 21CN, there might be a chance the DLM will put you on a 3db noise profile, with a higher sync speed, but that's likely to make things more unstable. You could try and counteract that by switching on interleaving, which will increase latency.

Food for thought.

EDIT: I think the 3db noise profile is only if you sync using ADSL2(+), so if you only have an ADSL1 router, forget that idea - or buy a newer router.

Edited by deleted (Wed 17-Aug-11 21:12:04)

Having quie a few resyncs over the past few days.

Did plug a phone in and did a quiet line test and all appeared to be OK.

Was on ADSL2+ but it dropped all the way down to 350 Kbps, did ask support about fixing the Noise Margin and they said they could if I put it back onto ADSL2+ but they also reckoned it would make line less stable.


Could this be something like an HR disconnect fault?

You might get lucky and get an engineer who is very thorough and gets a few more hundred kbps out of your line but I suspect it is more likely that Zen and/or BT will say relatively small fluctuation in synch speed is to be expected on a line with that attenuation.

I have a line with similar stats and I use the DGTeam firmware on a NetgearDG834GT

There is a version of that available for your router at

http://dgteam.ilbello.com/index.php?pid=11

I set my router to have a target SNR of 40% of the normal 6db and this gets me about 500-1000 kbps extra synch speed. I can get 3500 profile and sometimes 4000 when the standard settings would be 2500 or 3000.

Another point - recently my router was running 1000kbps slower than usual and SNR was varying between 1 and 5. I realised I had several extra routers, switches and access points under test and some or all of their power supplies were creating interference - worth having a look for any devices you can unplug at least temporarily.

Have you tried forcing the router to use only ADSL2 (no plus). For long lines, this is actually better. Worth a shot. There's no reason why you shouldn't be able to sync at 3dB on ADSL2, with interleaving, and still hold a reasonable connection. Fingers crossed this will give you enough extra sync speed to be well above the DLM speed profile border line that's causing you your speed issues.

Unfortunately, as another chap has said, I think for the length of line, the fluctuations you are seeing are expected.

Line modulation is fixed at ADSL so will have to talk to sales about getting it remodulated but its worth a shot I suppose.

Is there any mileage in getting the socket replaced with an NTE5 type and sticking an iPlate on?

I was corresponding with a member of the support team via the PM system on this forum and did ask for a price for getting this done but not had a reply, must have got bored and moved on.

Replacing a socket and not reconnecting the extensions if any, is £25+VAT
IPlate would be a seperate issue.

Generally if using twisted pair wiring on extensions, and ring wire is disconnected that is as good as an iPlate

What colour is the bellwire?