VoIP (Voice over Internet Protocol) is the process of making voice calls over an internet connection as opposed to a traditional landline. VoIP calls can be made from both a computer, and a regular (VoIP enabled) phone (the regular phone also connects to the internet). With a regular VoIP enabled phone, no computer is required!

A VoIP phone can be defined as an entity that is used to make telephone calls over the internet. A VoIP phone utilises the Voice over Internet Protocol (VoIP) technology wherein our voice is converted into digital signal that is transmitted over the Internet. VoIP phones enable you to enjoy the benefits of VoIP technology.
The VoIP technology is based on protocols, such as SIP, H.323 or proprietary ones like Skype.