Converting a digital signal back into an analogue one allows this transmission to take place losslessly – in other words a digital signal can be used to transmit data (and in this case voice) perfectly.

VoIP works in this manner. It digitalizes voice into data packets and then sends them and reconverts them into voice at the final destination.

There is more control over digital formats. They can be compressed, routed, converted and they are more tolerant to distortion (noise) than analog formats.

On the Internet the TCP/IP protocol is Universal. TCP/IP networks are made of IP packets containing a header (to control communication) and a payload to transport the data being transmitted.

VoIP use this technology to route across the Internet to reach its final destination.

The advantages of Internet Telephony used in this manner over a traditional voice network are that cost for voice networks are typically time based. The more time you stay on the line the more you'll pay. You also can’t talk to more than one person at a time.

In contrast, using VoIP you can talk as long as you like with as many people you like (simultaneously) – all that is required is that all parties are connected to the Internet at the same time. Costs are not necessarily time based.

Whilst talking on VoIP you can exchange ‘normal’ data with the people you are talking to – you can send photos, graphs and videos (and you can make video calls as well).