iMac 350s can't use v.90* If someone using an older iMac complains about slow connection speeds, this might be the problem. These iMacs have been on sale since 10/99. In the article it states Apple denies any problem and "blame for V.90 not working 'will be put on phone lines and ISP's.'"
There is a script available from Apple for iMacs with 56k modems that are having problems with unstable connects. It reduces the top speed to 33.6k, but is more stable.