Signed up for expected 512kbps, can't get anything!

Apologies if you�ve heard all this before! But help appreciated.
I signed up with an ISP a month ago (12-month contract!), and have had only about 30 minutes broadband service in that time. OK, I�m rather far from the exchange; ISP�s test gave likely speed of 512kbps. Each time the ISP tests my line they get a different answer; the last two such tests say that it failed the copper line test. They say they can�t do anything about that through BT Wholesale. When I call BT myself, they say my line passes the copper line test.
What to do? House wiring is old (router plugged into BT box with one-piece faceplate, no test socket inside). I hesitate to call BT out because of likely cost -- for 512k it�s hardly worth it. Maybe an NTE5 box would help, but what would BT charge for that? Comments appreciated!

What ISP?

What exchange?

What are the line stats reported by your router?

ISP is Newnet, exchange is 01981. Don�t seem to have any statistics � I was only online for a few minutes a couple of weeks ago. Router�s ADSL light flashes, Internet light is off. Log shows router is repeatedly trying to connect, reporting �ADSL link down�.

Have you anything connected to the phone line that isn't going through a filter? That includes burgalr alarms and Sky boxes.

Gently open every phone socket in the house, (one at a time will do), particularly the master. Check what wires are attached to which terminals.

Be very careful not to disturb T2 and T5. Gently disconnect and curl any others, particularly T3, out of the way. It is best not to cut them, and you don't want them making an electrical connection with anything when you put it back together.

do you have wired extensions or does the line terminate on this single non-NTE5 socket ?

do you know if the service is fixed speed 512k or variable rate MaxDSL "up to 8M" ? The latter may connect (slowly) when the former will not.

Everything (just 2 phones) goes through filters, & I�ve tried with the phones unplugged. Thanks for wiring suggestions; I�ll have a careful look at that!

yarwell: No extensions. There are 2 BT boxes in the house, each on a spur from a BT connector box where the line comes into the house.
My package is �up to 24Mbps� so I presume it�s MaxDSL.

Have you tried the router in both extension sockets?

Have you tried different filters?

Different modem cable to the phone?

In reply to a post by XDavid:

yarwell: No extensions. There are 2 BT boxes in the house, each on a spur from a BT connector box where the line comes into the house.
My package is �up to 24Mbps� so I presume it�s MaxDSL.

If you look at these pics, the master is the /1A and the extension the /3A. The visual difference is the cylindrical capacitor.

Thanks for that; I�m on the /1A master. All other suggestions here have been tried, except:
Just as I was thinking about disconnecting the wire on T3, suddenly broadband is working! For no obvious reason. It�s been on now for about 12 hours and still going.

BatBoy: re your query about statistics. I�m getting this (there's more, but I don't want to strain your patience!):

Mode: G.DMT
Type: Interleave
Line Coding: Trellis On
Status: No Defect
Link Power State: L0

Downstream Upstream
SNR Margin (dB): 4.8 13.0
Attenuation (dB): 63.5 31.5
Output Power (dBm): 12.3 13.7
Attainable Rate (Kbps): 448 764
Rate (Kbps): 352 448

The output power looks low. It is usually around the 19dBm mark. I don't really know what causes that, but I think it is something at the exchange end.

Re the stats you didn't post, the error seconds, RS Corr or FEC (same thing) counts, and the time since the last connection (approx) are useful. Loads of stuff about bin/bit loadings isn't at the moment.

When the power from there to you is low the connection speed can be low, as yours is. So I would take that up with your ISP.

Sorry I didn't make it clear when I asked about the wiring in the sockets. It is worth checking what colours are on which terminal numbers at each and letting us know.

The output power looks low. It is usually around the 19dBm mark. I don't really know what causes that

Only being able to use a smaller number of frequency bands, as the power per tone is fixed less tones = less power.

In reply to a post by yarwell:

The output power looks low. It is usually around the 19dBm mark. I don't really know what causes that

Only being able to use a smaller number of frequency bands, as the power per tone is fixed less tones = less power.

Ah thanks. I thought it was the other way round.

Though perhaps it is when the bins are available? Less power means fewer bits per bin?

it's only just managing to connect, with a low SNR and a low speed.

Ideally you want a single pair coming in and going to the socket where you connect. A tee off isn't helpful.

You didn't say what the router was, on such lines you may benefit by trying different ones like the 2 Wire BT business hub (via ebay) also set the mode to multimod eif available in case ADSL2 can do better (or force ADSL2 as a test).

less total transmitted power in this case doesn't mean less bits per bin because the Tx power per bin is the same, there's less total power 'cos of less bins in use.

Imagine 256 modems on the line but only some of them (the lower frequency ones) in action, perhaps ?

On very short lines, and in some scenarios, the power does seem to back off if the max speed is being achieved with a sensible margin. If the power backed off on a long line then the SNR per bin would drop and consequently the bits per bin. (NB SNR not margin).

Yes, that's what I was getting at. I understood what you said, and was trying to clarify my misconception .

Much appreciate all the helpful and rapid contributions about my problem!
Re the wiring: my star-wired BT master LJU2/1A socket has white/green blob on T2, green/white blob on T5, and orange/white on T3. No other wires are connected. I note that the orange/white is connected in the BT junction box to the white/orange which serves the /3A socket. I assume this is the bell wire; should I disconnect it at both LJUs? (One of my phones is elderly � BT Relate 80 � and I�m a little worried it may not ring. Guess I�ll soon find out!)
I�ve noted elsewhere on this most informative website that disconnecting the bell wire may help a lot, but I�ve ducked doing it so far, in the hope that broadband settles down if I don�t touch anything (I�m half expecting it to go down again!). But after 48 hours, it seems to be stable, if slow.
Here are all the stats! (Can�t get the tabs right -- hope you can deduce.)

Mode: G.DMT
Type: Interleave
Line Coding: Trellis On
Status: No Defect
Link Power State: L0

Downstream Upstream
SNR Margin (dB): 4.5 13.0
Attenuation (dB): 63.5 31.5
Output Power (dBm): 12.3 13.7
Attainable Rate (Kbps): 448 764
Rate (Kbps): 352 448
K (number of bytes in DMT frame): 12 15
R (number of check bytes in RS code word): 8 4
S (RS code word size in DMT frame): 4 4
D (interleaver depth): 8 8
Delay (msec): 8 8

Super Frames: 4038550 4311498
Super Frame Errors: 202 55
RS Words: 68655350 73295466
RS Correctable Errors: 801648 225
RS Uncorrectable Errors: 844 N/A

HEC Errors: 144 35
OCD Errors: 4 0
LCD Errors: 0 0
Total Cells: 60849323 0
Data Cells: 520924 0
Bit Errors: 0 0

Total ES: 120 0
Total SES: 0 0
Total UAS: 10547 0

Router is TP-Link W8950ND. (I also have access to an Novatech/AddOn GWAR3550 which I could try.) Haven�t found a multimode facility yet.
Not sure what you mean by tee off; the socket is master /1A and the microfilter�s plugged into that. Do you mean T-shaped microfilter? It was a cheap one; is that bad news?

That wiring is correct so no worries there thank goodness . However the ring wire would be better disconnected. I would do it at all three points, just to be sure - both sockets and the junction box.

The problem with it is that it acts as an antenna, picks up wireless noise, and feeds it onto the line. Probably only feeds it on at the master, but given what you described I wouldn't be certain in your case.

Your old phones will ring anyway as the ADSL filters incorporate circuitry to make them, as do most modern phones. It is only certain phones used without filters that may stop ringing. So it is usually recommended when leaving a property to reconnect ring wires, just in case the next occupier doesn't have broadband and does have phones that need them. That's why we say don't cut them.

It will be interesting to see the stats after ring wire disconnection.

it sounded like you have a T shaped wiring setup with incomer going to two sockets. One would be ideal - can you remove the other ?

check the stats are the same with no phone in the microfilter then you'll see if the filter is OK

Many thanks. Can't remove a socket however.
I still don't really know why broadband was down for 2-3 weeks, almost from the day I signed up for it, then suddenly started up 3 days ago and has been chugging on ever since!
Anyway, I'm not complaining; even slow broadband is bliss after Onetel's snail-like dial-up, which seemed to be getting ever slower.
Again, thanks again to all you guys and to this excellent site!

Finally got around to disconnecting the bell wire, as per your suggestion. Result: immediate increase in sync speed from roughly 350k to 600k (no detailed stats yet as the line went down just afterwards!)
Problem: one oldish phone (maybe 15 years old) no longer rings. It's connected through a microfilter, but it was a cheap microfilter -- could that be the problem? I'd rather not bin the phone!
Though broadband now works, it goes down rather too often and can take a few hours to come back. Would a suspect central heating room thermostat be enough to cause the line to go down?
Many thanks

microfilters should regenerate the ring signal, there are some bad designs that don't (and don't filter the ring wire either) so I would change that for a better one.

Many thanks, Phil. After some online research, I see that even supposedly good microfilters aren't necessarily much more expensive.
This is rapidly turning into a crash course in telecommunications for me, for which I'm grateful to you guys.

Final postscript to all the above, I hope.
It's clear now that all the initial problems, plus later ones of ADSL going down sometimes for several hours at a time, were due to that bell wire. Strange the ISP people never mentioned it. Speeds now regularly above the promised 512K.Thanks to RobertoS.
A better quality microfilter installed for £3.50: old phones ringing their heads off now, and for all I know it contributed to the stability of the line. Thanks, Phil.