Simple answer don't touch, as if you break stuff you could be landed with a bill to fix it all and upset neighbours in the process

Annex M is a facility on ADSL2+ that requires the ISP to activate it.

It is also the last thing you could possibly want - it would be a disaster for you. Its purpose is to increase the upstream maximum speed from 1.3Mbps to 2.5Mbps.

On ADSL2+ the upstream frequencies are below the downstream ones. What Annex M does is double the number of frequencies allocated to upstream, taking those frequencies from the bottom end of the downstream.

The effect is that unless the downstream connection speed is above 16Mbps on Annex A, then you lose at least 2.5Mbps downstream speed, but at that level of downstream attenuation the upstream attenuation is also high and the increase above 1.3Mbps simply doesn't happen. Lose-Lose!

At 24MBps downstream on Annex A then the strength of the top-end downstream frequencies is enough to compensate fully for the loss of the bottom end ones. and the attenuation each way is obviously much lower. So the full upstream increase is obtained. Win-Win!

In between those two extremes there is a sliding scale of downstream loss against upstream gain.

Your line just isn't suitable.

I see. Now it makes a bit more sense. Thanks for the in depth explanation.

I've read somewhere that if I see no difference from speed testing the connection directly with the test socket vs nts5 socket than I shouldn't invest in a vdsl filtered faceplate and cat5 cable do you know if that's true?

If the adsl2+ stats are no better in the test socket then investing money in faceplates and cables won't make much or any difference

Noise margin is too high at 10db this will lower the speed. This happens if the line is dropping normally or if the routers doing some funny business.

Can you get fibre? It seems unlikely not given the location.

Can you get your details here and post back the results?
https://www.dslchecker.bt.com/

Edited by ukhardy07 (Mon 06-Mar-17 23:19:23)

Nope. Just ADSL available.

What do you mean the line is doing? Connection is super stable.

Simply put you'd only be put on a 10db noise margin if the connection is unstable.

You mention the router can manually edit the noise margin, is this something you setup? I guess this could be the issue too?

Basically at 6db you'd have faster speeds but more chance of the line dropping.
Out of the box you will be on 6db, so for some reason dynamic line management has decided that's too unstable and changed it to 10db. This lowers the speed but makes it less likely to drop.
Very stable lines get 3db noise margins but one of your length is unlikely to get that.

Yeah it's a setting on the router. I can disable it and set the snr to something else. What would you recommend?

+1

Just leave it at whatever it decides next time you sync, I mean do not impose any SNR setting yourself! Then take the stats immediately and post them. Do not do this right now. Connections made well inside daylight hours are nearly always higher than ones made at dawn, dusk or night-time.

We need to see your stats as the system wants them in order to advise you what to do.

Edited by RobertoS (Mon 06-Mar-17 23:32:42)