Massive difference in max speed

[Stumpy]

As some of you will know, I've been having massive problems with my line for 2 months or so now, resulting in two lots of "lift & shifts" at the exchange. I'm just coming out of the second lift and shift however am rather confused about my resultant speed changes.

Prior to my current problems, I was getting a stable connection of around 4-4.5Mb. Checking the tables with respect to line attenuation/distance from the exchange, this was about right.

During the last round of "repairs", a sky contact told me that they have a different set of information at Sky, showing the length of my line as being 5.5 Km, which translates, according to their information, as a max speed of 1.5-2Mb.

The latest "fix" was carried out a few days ago, but resulted in my non-capped router disconnecting constantly, at a speed of 2Mb. I was told this was because more information was being "forced" down the connection than it could cope with, resulting in large amounts of errors and therefore disconnections. They therefore capped me initially at 1Mb, although said they may be able to tweak it slightly to get closer to 2Mb. Their argument is that, because their records show my distance as 5.5Km, even though I did originally get 4Mb downloads, they couldn't do anything about it if I could now only get 1Mb.

Now, I've left my router during all this time plugged into the test socket (ie, test socket, then filter, then Sky supplied cable to the router in one side, and one telephone in the other).

This is the stats I pulled off my router about half an hour ago, which is approximately what it has been all weekend, since they "fixed" the line:

Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 25.6 16.0
Attn(dB): 52.0 25.0
Pwr(dBm): 15.9 5.3
Max(Kbps): 1376 1076
Rate (Kbps): 1024 416

(note they changed it to G.DMT because it gave less errors)

I have just reconnected my ADSLNation faceplate, connected the router directly into that (rather than via an extension), and now get:

Mode: G.DMT
Channel: Interleave
Trellis: ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 17.8 16.0
Attn(dB): 52.0 31.5
Pwr(dBm): 8.2 3.7
Max(Kbps): 5152 1124
Rate (Kbps): 1024 416

Can anyone explain these figures to me? I'm aware that the faceplate does filter out some interference, but these figures are drastically different, and I had been told previously that the best possible connection I can get would be directly via the test socket which obviously is not the case here.

Does this indicate that I have a particularly noisy line? I've not noticed anything on the telephone. There also appears to be quite a difference in the "Pwr" figure - is this an indication of anything?

Will this change therefore mean that I will be able to go back to my 4Mb+ connection speed, or are Sky's figures pulled from the exchange, which means that I can't affect them?

[simonmpoulton]

Chances are you had a dodgy filter you were using from the test socket. The ADSLNation faceplate contains one of the highest quality filters you can get!
Your SnR indicates that you have been capped severely and you should be able to get 5mb without problems. Get onto SKY and get them to raise your cap as your SNR shows you have plenty of noise in reserve!

[Stumpy]

We used several different filters, a different router, a different wire from the router to the test socket, whilst on the phone to Sky, all of which gave exactly the same readings (with slight differences - for example unsurprisingly using a different, much longer, cable from the router to the test socket increased the errors). During the course of my problems with this connection over the last 2 months, I have used at least half a dozen new (brand new, Sky provided, still in plastic wrappers) filters. None of them gave any different readings.

Edit - I'm aware I've been capped - at 2Mb my connection was dropping constantly and I was told this was because my router was trying to connect at too high a speed - which is why they (temporarily at least) capped me at 1Mb.

[Isitme]

I think what you have to understand that the Test socket is the main connection to the phone line. Everything you plug into the phone anywhere in your house goes through the Test socket. If you are getting a poor result when you plug into it directly it means a) the plug is not making proper contact with the socket or b) the filter you are using is u/s.

If you leave the router plugged into the ADSL faceplate and phone Sky they should be able to configure your line to 4-5Mb.

[Stumpy]

I suppose it is possible that there is some design flaw in the filters I have been using whilst in the test socket - they were all the standard "dangling out of the socket" types that Sky sends out, and I understand that the ADSLNation faceplate is going to be a better quality than those - but it just seems strange to have such a large difference.

But my main question is, those figures that I put in my original post - do they indicate anything other than my faceplate filter works exceptionally well? I know what the attenuation and noise margin indicate, but not sure about the power fluctuations ...

I was also rather confused as to why Sky's equipment and my diagnostics show such a difference in all of the figures when the test socket is supposed to be the purest connection point.

[simonmpoulton]

If i'm not very much mistaken your power values are for Transmit power!
Basically the lower the value the less power it's using at the exchange to send your signal out down your line. Higher quality phone lines with new cable should have lower powers and lower quality lines use more.

[Stumpy]

Hmmm ... so it takes about half the amount of power to send a signal down my line WITH my faceplate, than without.

I'm assuming this then means that, as nothing else has changed, the filters that Sky provide are very sub-standard.

[Isitme]

I was also rather confused as to why Sky's equipment and my diagnostics show such a difference in all of the figures when the test socket is supposed to be the purest connection point.

As I explained before, it is. All I can suggest is that the filters supplied by Sky are not functioning properly. What you can try is connecting your router using a dial up modem cable with a standard BT plug. The one used to connect your Sky box would do. You should get very similar figures to the ADSL faceplate. If you do, you will know that the Sky filters are the problem.

[Stumpy]

Hmmm .. perhaps it isn't the filters after all. I've just had a disconnection, using the faceplate, and the stats now show my max connection speed as much lower:

SNR (dB): 16.8 16.0
Attn(dB): 52.0 31.5
Pwr(dBm): 15.6 5.2
Max(Kbps): 2208 1080
Rate (Kbps): 1024 416

[Isitme]

It looks like there is a large noise spike causing your connection to drop and resync at a lower rate. Try downloading and running Routerstats Lite for a while and see what it shows. Get it from here-
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