What Is VoIP and IP Telephony, and Are They the Same?

An Explanation of IP Telephony and VoIP

Girl on video call on tablet
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Most people, including consumers and those in the media, use the terms Voice over Internet Protocol (VoIP) and IP Telephony (IPT) interchangeably, equating one to the other.

However, to put it simply, VoIP is really just a subset of IP Telephony. 

VoIP Is a Type of IP Telephony

That may sound confusing but since the word "telephony" refers to telephones, we can assume that Internet Protocol telephony deals with the digital side of telecommunications, and it does so with the internet protocol called Voice over IP, or VoIP.

What this means in the literal sense of the words is that you're transferring voice using the internet. The protocol defines how voice is to travel over a network, similar to how the HyperText Transfer Protocol (HTTP) defines how data is to be understood, transmitted, formatted and displayed in web servers and web browsers.

To see it in a broader picture, think of IP Telephony as the overall concept and VoIP as a means of transmitting voice to implement this concept. An IP Telephony system can, for example, be an IP-PBX, which has VoIP and its standards (SIP, H.323 etc.) along with many other things (e.g. CRM), geared towards better productivity.

What Does It All Mean?

IP Telephony is a way of making a phone system digital to take advantage of the internet and any hardware or applications attached to it.

The main aim of IP Telephony is to increase productivity, which suggests that the technology is better referenced in business environments.

On the other hand, VoIP is simply a digital transport vehicle for phone calls. In its different flavors, it works towards offering cheap or free calls and to add more features to voice communications.

There are many other ways to put the difference simply. Some describe IP Telephony as the overall experience of communicating effectively and reliably using internet protocols; this being achieved by harnessing the power of VoIP by virtue of the latter’s user-friendly features.

The difference is quite subtle, isn’t it? However, I still think that using the two terms interchangeably can be acceptable in many contexts, even if just to avoid confusion.

How Do I Make Free Internet Calls?

There are lots of ways you can make free phone calls over the internet. The easiest way is to download an app for your tablet or phone because then you can use it just like a regular phone but you don't have to worry about it using up your calling minutes.

Viber, Skype, Facebook MessengerGoogle Voice, BlackBerry Messenger (BBM), and WhatsApp are just a few examples of ways you can call other people with those apps for free, all around the world.

To make free calls from a Mac, specifically, see these VoIP Apps for Free calling on a Mac.