Symptom
An alert box with this message appears when connecting to the Internet with your internal Apple modem:
"A crossed connection has been detected. Please check your modem settings and try again."
Solution
1. Choose System Preferences From the Apple menu.
2. Click Network.
3. Choose Internal Modem from the Show pop-up menu.
4. Click the Modem tab.
5. Choose Apple Internal 56K Modem (v.90) from the Modem pop-up menu.
In the event that your Internet service provider uses a v.34 connection protocol, choose Apple Internal 56K Modem (v.34) instead. Contact your ISP if you are not sure whether to use v.90 or v.34. For more information, see technical document 30734: "
V.90 Protocol: Connectivity Discussion"