If your base station came with an internal modem, and you have a dial-up account with an Internet service provider (ISP), you can connect the base station modem port to a standard phone line and use PPP to connect to the Internet.
Make sure to have your account information ready before you use AirPort Utility.
Your ISP account name (user name) and password
Your ISP's dial-up modem telephone number
Whether you want to configure TCP/IP manually or using PPP
Your IP address (manual configuration only)
The address of your Domain Name System (DNS) server
Click Modem to set modem options, such as how long the modem will remain idle before disconnecting, your country code, and other options.