Here are two methods for connecting the Symbian OS emulator to networks and to the Internet. Reading each one's overview will help you choose the most suitable method. Symbian recommend using Ethernet where possible:
If the above two methods of connecting to networks and the Internet are not suitable then you can edit the comms database as described in Comms database configuration tools. This allows modems, ports, and ISP settings on the emulator to match the hardware and settings available on the PC.
You can test your connections with How to test comms settings.