666 - Your modem (or other connecting device) is not functioning.
Applies to Windows 95 & 98:
The telephon.ini file in your \%systemroot%\ folder may be corrupted, missing or damaged. Locate and rename the telephon.ini file to
telephon.old.
(%systemroot% is normally c:\windows.)
Re-start your computer and then run the tapiini.exe file located in the \windows\system folder.