Types of VoIP Service

PC to PC
PC to PC VoIP is a software-based service. It is a free service. PC to PC VoIP allows people using their computers to place calls to each other for free. Of course, you both need to be using your computer in order to place the call.

PC to phone and vice versa
PC to phone VoIP is a software-and-hardware-based service. It allows you to use your PC to call a landline or mobile phone. This type of VoIP does not come for free, however, but the rates are considerably lower.

Phone to phone
Phone to phone VoIP is a hardware-based service. For phone to phone VoIP, the caller and the call recipient can use their phones to call each other using the Internet. VoIP converts audio sounds into data packets and transfers these packets over the Internet. The packets would then travel from one open router to another following the built-in packet address. Once the packets reached the call recipient, they would be converted back to audio sounds.