ADSL Max connection problems all of a sudden

In May of last year I moved from my 1MB/s Pipex ADSL connection to a Zen ADSLMax connection. All has gone well for the last 11 months, with syncs between 3.8-4.8Mb/s, with a 55db line attenuation and between 6-3db noise margin. Downloads were pretty much constantly around 400KB/s.

Recently I decided to see what my connection would be like without interleaving. I wanted better pings and thought I'd just try it, if it damaged my speeds too much I could turn it back on. So I requested it to be turned off. The connection was still ok for weeks, then one day (about 2 weeks ago) my sync speed plummeted. Suddenly I was connection at around 2Mb. The following morning I reset my router and all seemed to be back to normal syncing at 4Mb. But unfortunately later in the day the connection plummted again, first to 3Mb, then to 2.5, then to 2.1.

Now if I leave my router (without resetting) it starts at about 2.7Mb with a attenuation of 54db and a noise margin of 16db! As the day goes by the noise margin will start to drop, down to 9, to 6 and then to 0. It'll then resync to either 2.5Mb or 2.1Mb and the noise margin will go back up to 9db. Within hours the noise margin will drop to 0 again but the connection will stay at either 2.5 or 2.1, at that point I normally go to bed so I have no idea what happens after that

If instead I reset my router in the morning it will resync at over 4Mb but still has a noise margin of 9db? Why is it syncing with that noise margin? I was under the impression that ADSLMax was supposed to sync as high as possible with a 6db noise margin?

Anyway last week I requested Interleaving to be turned back on. Which Zen tell me is now on according to BT's system. But the problem hasn't changed. 54db attenuation and 16db noise margin during the day (or 9db if I reset it to 4Mb), 55 attenuation and 0db noise margin in the evening and night time.. WTF is going on?

Edited by DonnieD (Thu 26-Apr-07 14:07:19)

As I understand it the SNR Margin will drop until the first of

1) 8128 kbps is reached
2) 6 dB is reached
3) the line becomes unreliable

I guess your line has become unreliable.

What happens if my line has suddenly become unreliable? Will BT actually do anything about it? Is there anything I can do about it?

Edited by DonnieD (Thu 26-Apr-07 14:35:49)

You will need to do a little digging yourself. Something does appear to have altered the stability of your connection, more than just interleave being changed alone I'd guess.

Check your internal wiring.

http://www.dslzoneuk.net/socket.php

Check your modem statistics, and post them if you are not sure what they are indicating.

http://www.dslzoneuk.net/adsl_line_stats.php

Also look here for general info

http://www.dslzoneuk.net/adslmax_explained.php

I tried the first link, but I don't really think it applies to me. My socket is pretty messed up, but not in a way that I think should cause any problems, well it hasn't for the previous 11 months. What I mean is that I used to have ISDN. Originally I had one socket downstairs. The BT engineer made that the second socket and led a wire upstairs to another socket which he made the master socket, this was connected to the ISDN box. When I first got ADSL nobody came out to disconnect the ISDN box, so I did it myself by removing its internal wiring into the socket. I then disconnected the socket downstairs as its never used. So now all I have is the socket upstairs with two internal wires connected to it coming from the wire that leads up my stairs from the outside line (I have no face place on, the filter is plugged direct into the internal socket).

Here's a pic of my line stats:

http://img124.imageshack.us/my.php?image=statspc2.gif

If your line starts to become unstable the DLM may increase your Traget Margin from 6dB to 9dB to help cope with the swings in noise levels.

In reply to:

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If your line starts to become unstable the DLM may increase your Traget Margin from 6dB to 9dB to help cope with the swings in noise levels.

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According to the OP's screenshot (above) his SNR is at 16 dB so it looks as though he is on the highest setting of 15 dB already.

Ok, as an update this is what happened for the rest of the day when I posted this thread:

As the pic I posted showed my connection was synced at 2720 kbps with a 54db attenuation and a 16db noise margin at around 2pm. About an hour later the noise margin started to drop, first to 15db. Within another 45 minutes the noise margin was down to 3db, my attenuation was up to 55db and the connection had resynced at 2176 kbps. Within another 10 minutes the noise margin dropped to 0. Over the course of the next hour it went back up to 6, then 7 and then back to 0, which is when I gave up and went out.

Yesterday when I came in from work I turned on my router and PC and found my connection at 4.1Mb with a 9db noise margin. This wouldn't normally be unusual, if it was early in the day. But this was 5pm. I tried downloading, and for the first time in weeks I was getting my normal 400+KBps downloads. This stayed the same for the rest of the evening until I went to bad at 10pm (hard day ).

But low and behold when I got up today (having left the router on all night) my connection was synced at 1984 kbps with a 0db noise margin The strangest thing though is that only minutes later when I reset the router it synced at 2496 kbps with a 9db noise margin!! How on earth can the router be synced at 1984 kbps with a 0db margin and when reset sync straight to a higher speed with a much better noise margin?.. does that make sense or is it as crazy as it seems to me?..

In reply to:

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How on earth can the router be synced at 1984 kbps with a 0db margin and when reset sync straight to a higher speed with a much better noise margin

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A noise source has been along and then gone away, the router was locked into a lower speed using frequencies that avoided the noise. When you rebooted it was able to exploit the frequencies the noise had previously blocked out.

"My socket is pretty messed up, but not in a way that I think should cause any problems"

The first thing that needs to be done where problems such as yours are apparent is to eliminate all possible internal causes. That means either using the hidden test socket of the NTE5 type master where fitted or physically disconnecting all internal cabling from the master, connecting to it and monitoring the result in that state.

If improvements are seen using either method, then you have an internal fault that you are responsible for. Be aware that if you or your ISP arrange for a BT engineer visit and he finds a fault on your side of the master socket, it's possible that a