Mine used to do that, so I got shot of it and replaced it with a router modem and NIC card.
The NIC is a "pcworld" £10 cheapie - works perfectly and the modem router is a
SAR110 which has been an excellent buy.
Before I got it, I looked round the
adsl guide and the SAR110 seemed to be ideal.
I didn't really know a thing about networks and so on, so I just plugged it up, called Solwise, and one of the blokes from their tech dept talked me through the config (he even "schpielled" the IP address numbers out to me off the top of his head). I then booted it into my mandrake install and he did the same, it took all of 10 minutes.
I haven't bothered to look back. I will say that the "freezes" and the wait for the speedtouch to reinitialise between where what drove me away from it, apart from that, it was fine.
regards
John