Noise Margin

[#1]

How is the extension socket upstairs connected to the master socket - via an extension cable that plugs into the front of the master socket or connected to the rear connectors of the lower removable panel of the master socket?
I.e.was the socket upstairs connected to the master socket when you tried plugging the router into the master socket?

[#2]

The socket upstairs must be connected via some internal wiring in the walls, there aren't any external wires. There's no other obvious connections from the master socket downstairs. Sorry, that probably doesn't help much!

[#3]

Have a look at the black background picture here http://www.wppltd.demon.co.uk/WPP/Wiring/UK_telephone/uk_telephone.html - You are actually looking at the back of the master socket (the bit against he wall).
The lower removable plate has some IDC connectors (identified by the green lines on the picture). Are the wires you refer to connected to them? If so, this is you extension cable which probably goes back into the wall and upstairs. With the lower removable plate removed, this extension socket is disconnected so does not interfere so you get a better sync rate. With the cover replaced, the extension socket is affecting the sync rate.
If the above sounds correct say so and I'll explain what to try next.

[#4]

Depending on the make of Router it might be worth running RouterStats for a few days and getting to understand the fluctuations in SNR that occur on your line. Then try and tweak to a set of values that give you the blend of stability and speed.
I use a DG834GT (ex Sky) with the DGTeam firmware. My line is stable (one dropout per 2-3 weeks) at 6240-6400 (to hold a 5500 BRAS)  with SNR tweaked down to 4-5dB. If I reboot during the day I can see 7500+ sync's, but they soon degrade as night falls back to 6300 ish.
Most neighbours run 4500 BRAS profiles.

[#5]

Ok, my master socket is very much like the first one listed on http://www.kitz.co.uk/adsl/socket.htm
If you take the face plate off and turn it around, there is the user socket in the centre and the wiring connectors in the top right (white with blue into 5 and blue with white into 2 - I've tried removing the bell wire as it can apparently be a source of interference).
Ooo - I've just reconnected with the bell wire removed and get the following stats:
ADSL Link  Downstream  Upstream
Connection Speed 7072 kbps 448 kbps
Line Attenuation 40 db 13 db
Noise Margin 3 db 21 db
Noise Margin seems to hang around 2-3 dB, occasionally 4 and has hit 6. Perhaps bell wire interference then? Is it worth removing the bell wire from the extension socket too?

[#6]

That looks better... It was the bell wire that I was going to suggest, and yes, the bell wire should be removed from both ends (plus any other wires not being used) and isolated (i.e. kept as far away as possible from the remaining connected wires).
Also i'll throw in a FYI... the netgear is not very accurate at reporting noise margin (SNR) so seeing a wide fluctuation may not actually indicate that is so. Mine used to go -ve (-2 billion) but still kept the line in sync) so take those readings with a pinch of salt.
You may want to look to see if there is a later version of firmware for the router - and remember to get hold of the recovery software just in case things go funny on the upgrade. There is also unofficial firmware from DGteam which appears a lot more stable than the Netgear versions - see http://dgteam.ilbello.com/ - but as always... use at your own risk (although the recovery software can get you going again).

[#7]

Excellent, thanks for all your help If the thing does reconnect overnight I think I can be safe in the knowledge that my line speed should increase to around 4.5-5Mbps at least, always handy

[#8]

Hi snarf,
only just got back, I see Peter has pretty well got to the bottom of things for you, yes the ring wire is what's causing the main problem. You should only have Blue-white on 2 and White-blue on 5 at the master and all extensions. Spare wires should be neatly coiled and tucked back so they don't touch anything when the sockets are replaced on their boxes.
Don't forget the powerdown method when disconnecting.
Depending on how many you've done this evening, I'd leave until tomorrow. You have the prospects of some excellent performance compared to what you have had.

[#9]

HI again,
I've just re-read the rest of your information, and you should now get the same performance plugged into the socket on the other side of the room (no extension) as you got in the test socket, but as I've already said I would not do any more disconnects tonight.
The extension cable is now the only thing of concern. can you describe it.
Most extension cables that plug into a socket and have another socket on the end have all four wires connected, and are not twisted pair cable and will pick up interference and reduce your performance (especially considering the equipment it is close to!).
You could do one of three things -
1) purchase an extension cable that is a single pair of twisted wires only connecting 2 & 5. Such things are not that common or especially cheap.
2) purchase a "modem" extension cable which has the same plug and matching socket on it as your router, BUT it should only have the two wires and be twisted pair. Plug your filter into the socket on the other side of the room, and then plug the extension cables into it.
3) the best bet - purchase some proper cable for fixed extensions (to spec.CW1308) as used by BT, 2 pair (4 wires) similar to the wire you've already seen at the back of your master. The wire colours will be pair 1 Blue-white and White-blue, pair 2 Orange-white & White-orange. You don't want the version with the 3rd pair (greens). Also an extension secondary socket and a cheap (plastic) punch down tool sometimes called a krone tool.
Install this new fixed extension at the most convenient location and connect it to the back of the extension socket on the other side of the room.
If you want to go down this last route, | can give you some further information about the connections, prices and some places you can buy from.

[#10]

Ok, cheers for that - if I have any more issues I'll look at perhaps improving the extension cable. One other question, would one of the new BT i-plates make any difference? I've noticed that they have an extra filter on the plate which is "supposed" to improve performance (I'd be interested to know if any has seen this improvement, as they quote around a 1.5Mbps increase).

[#11]

As I said, can you try and describe your extension cable? It's difficult to say what sort of effect it will have except it is likely to be degrading your performance!
The I-plate primarily deals with the bell wire issue (which you've just dealt with by disconnecting the orange wires). The filter in the i-plate electronically isolates the bell wire (but you don't need the bell wire anyway). It is primarily for people who don't have the ability to go fiddling with wires.
That said, it also has a common-mode filter on the main pair. A number of users have said it makes absolutely no difference to their performance (the main effect being the bell wire - as you've seen). Some users have noticed an improvement BUT any improvement will be undone by substandard or incorrect extension cables.
My recommendation would be it will be a waste of time & money unless you sort out the extension cable even then it may be of no benefit.
Where is the modem/router at the moment, can you post the current stats?
Could you also post some stats tomorrow (taken between 9am & 3pm) so we can asses the benefits of what you've done?
Thanks.

[#12]

The extension cable does seem to have 4 cables in it, it's basically a plug in dual splitter that also has an extension wire (which is the one that runs around the room and I plug the router into the other end).
Current stats are:
ADSL Link  Downstream  Upstream
Connection Speed 7264 kbps 448 kbps
Line Attenuation 40 db 13 db
Noise Margin 6 db 25 db
I'm not sure I'll be able to post anything tomorrow as it's a trip to IKEA then a party in the afternoon ( :D), but I'll be interested to see tomorrow evening if the router has decided to reconnect (I'll check what time it reconnected if it does). I'll check during the day on Sunday aswell.
As I've said though, the fastest I'd ever managed to get it to connect before was around 6500kbps, and that was without any other equipment connected (when we first moved in!) - the average reconnect speed in the evenings was around 5500kbps, so getting 7264kbps is a marked improvement!

[#13]

Well I've got to say that does look quite good if you are running from the extension cable.
One thing you could try then is watch your SNRM figures whilst switching on or off all your other kit TV etc and see what effect if any there is. If there is none, well carry on as it is and see if things continue to be ok.

[#14]

Ok will do, I'm back at home (weather too bad to go out) and the line hasn't dropped and the SNR is now stable at 6dB, so all is looking good