I hope somebody can shed some light on this. I've encountered this problem with both Lucent and PCTel chipsets. Under WinXP, the modems install fine. You can do the diagnostics and they appear to run fine as well. But when you dial, you get a "No dial tone" error. There is nothing wrong with the connection, as replacing the modem allows me to connect. Why in the world does this happen? Anybody know of a fix? I will be eternally greatful.