ADSL upload speed very slow!
 

I have just successfully installed a Fujitsu FDX310 usb adsl modem on a Red Hat 9.0 system and while I get good download speed, I get a very slow upload connection. I used the web tool at "adslguide.org.uk" to perform the measurements and this reports a download speed of ~450 Kbps BUT upload speed is only 3 Kpbs!!

The line is ADSL 512 Kbps download, 256 Kbps upload to a Pipex ISP host. Under Windows, on the same machine, the tool reports a download of 468 Kbps and an upload of 243 Kbps. So it looks like I have some kind of configuration issue that is severely limiting my upload bandwidth?

Any ideas where to look?