Hi, I am currently having a problem with my ADSL connection, one which I have contacted my ISP about but am reluctant to pursue without more knowledge.

When I came back from working abroad in August I noticed that my connection was much slower than it was before I left, going from about 5mbps to something closer to 0.5mbps. I contacted my ISP and this was soon sorted, but soon after I noticed another strange thing -- I would randomly get periods where I would get no internet connection. I noticed that my SNR was dropping to very low levels (I'm on 12db interleaved but sometimes it would drop to 3/2 or so). Sometimes it is the case that I can still talk to people over VoIP and they can hear me, but I can't hear them, or they have lots of jitter/lag as they speak.

About a week after that I noticed that there were times where the SNR was fine but I could not access new websites. It is strange, because when it happens other network activity like IRC/torrents/Steam etc keep on working and (for example) I can still talk to people on IRC/Steam or continue to download torrents which were downloading before the problem, but I can't access any websites, they just time out, say that the connection was interrupted while the page was loading, or say that the connection to the server was reset while the page was loading. I noticed that when this happens my router lists my output power (dBm) as going to either 0 or 512 (I assume these must be the lower and upper limits for this), it does this on either the downstream or upstream (or sometimes both) and causes this strange problem. If I reboot the router, both the SNR and the output power issues go away and I can access the internet again, and most of the time if I wait for 2-3 minutes it will start letting me access the internet properly again.

I have done the following

* Tried two different types of router
* Tried two different DSL cables
* Tried the master socket
* Tried three different microfilters (which I have also tested elsewhere, they all work fine)
* Tried disconnecting the phone

My ISP was talking about sending someone out to take a look at the problem, but my worry is that when they come to check it out it will not be occuring (it is intermittent, sometimes it happens multiple times in a day, sometimes it takes 2 days to occur). Is there anything specific you think it might be causing this, and as such is there anything you would recommend the person who comes to check it out should be asked to take a look at?

Thanks. :)