Setting Up Network on your Macintosh OS X

In the Apple menu at top left, click "System Preferences".
Choose the "Network icon".
For location, choose "Automatic".
For show, choose "Internal Modem".
Under the TCP/IP tab, for "Configure," select "Using PPP"

Network - TCP/IP

Click on the PPP tab
Type "PShift" in the Provider box.
Type your local access number in the Telephone number box.
Type your username in the Account name box.
Type your password in the Password box

Network - PPP

Click the PPP Options button
Make sure only the following are checked, and click "OK"

Network - PPP Options