I've recently seen users encounter problems when trying to use a cell phone to connect to an ISP or a RAS server after upgrading from Windows 9x to Windows XP. When you use a cell phone keypad to dial the number and make a connection, you can hear the tones and you know that the server is responding. However, you can't use DUN to make the same connection through an XP PC. I discovered that the problem is the dashes between the groups of numbers (i.e., between the area code, exchange, and last four digits). If you eliminate the dashes, you can connect.