These two terms are used interchangeable in most cases, but technically speaking, they are not quite the same thing. The three terms that personate one another are Voice over IP, IP Telephony and Internet Telephony. They all refer to the channeling of voice calls and voice data through IP networks, namely LANs and the Internet. This way, existing facilities and resources that are already used for data transmission are harnessed, thereby eliminating the cost of expensive line dedication as is the case with the PSTN. The main advantage that VoIP brings to users is considerable cost cutting. Calls are also often free.
This along with the numerous advantages that VoIP brings has caused the latter to become a major technological element that has gained worldwide popularity and claimed the lion’s share of the telephony market. The term Computer Telephony has emerged with the advent ofsoftphones, which are applications installed on a computer, mimicking a phone, using VoIP services on the Internet. Computer telephony has become very popular because most people use it for free