In February 1995, VocalTec produced the first Internet Protocol Telephone software. The call quality was poor but the phone calls were free. In that (long ago) era Internet Telephony (IT) was compared to the CB radio craze of a generation ago. Those using, or working on, IT were referred to as 'the lunatic fringe' by those in conventional telephony. Today, Internet Telephony is accepted as mainstream technology. IT has become the logical successor to the circuit switched telephony that evolved over the past 125 years. What is Internet Telephony and why has this rapid change happened? 

This talk contains an overview of IT, from its start as a cheaper way to make phone calls from PC to PC up through today. This includes both a description of the technology that has already been created and the technical hurdles that still lie ahead. Conventional telephony is complex. Can it be replaced with a simple technology without eliminating the features that consumers know and love? The talk also contains a discussion of the economics of IT. Why are businesses embracing it? 

Finally, we include some visions of the future. Where  will this all lead? Is it all hype? When are we going to see IT in the marketplace as a mature technology - or is it one already?