LindowsOS 4.5 comes with Session Initiation Protocol, or SIP, technology that allows PC users to call up others using the same technology. Customers
will get a unique number to send and receive calls and use features such as four-way conferencing and 800-number access. Using this number and a
virtual keypad, they can connect to the phone number of anyone with a SIPphone, videophone or SIP-enabled computer.