By default Phone Dialer is not added to the communication menu. Therefore unless you know where to find it your immediate assumption is that Windows XP no longer uses Phone Dialer. As you can see, from the instructions below, Phone Dialer is alive and kicking. It's just keeping itself well and truely under wraps!
1/ Click the Start button
2/ From the Start menu click Run
3/ In the Run dialog box type: dialer.exe and press Enter
4/ The dialer application will now open