The interesting thing about VoIP is that there is not just one way to place a call. There are three different "flavors" of VoIP service in common use today:
-ATA: analog telephone adaptor- The ATA allows you to connect a standard phone to your computer or your Internet connection for use with VoIP.
-IP phonaes :IP phones connect directly to your router and have all the hardware and software necessary right onboard to handle the IP call
-Computer-to-computer: There are several companies offering free or very low-cost software that you can use for this type of VoIP