How do i activate windows server 2008 r2 by phone?

Windows server 2008 r2 is sold with an activation tool. After installation one will be notified after 60 days of the need to reactivate. Activation is performed with a utility supplied with Windows. It can be performed using one the Internet. Here, the utility transmits data using an Internet connection. It can also be done using a telephone call where telephone activation code must be read to the Microsoft agent who supplies a code to input into the utility to activate Windows. Finally it can be done using a modem. The utility sends data to the activation centre using a phone line accessed through the modem.