Here's an answer : it's muddy. A few weeks ago, a blogger gave a quick history of Voice Over IP. Trouble is... it's basically wrong. VocalTek no more invented voice over IP than Gutenburg invented books. (And that's giving a lot of credit to VocalTek, whom I respect nonetheless.) Just like Ana Nicole's baby, VoIP has many, many fathers - and it mucks up prior art big time. Let's look at some of the happy fathers not mentioned by the bloggers, and probably not mentioned by the patent attorneys, either :
- H.323 was finalized in November 1996, written by many of my fellow employees at PictureTel, firmly establishing that nearly all of the ideas it contained were known in the community for at least two years prior, including naming conventions, gateways, etc.
- Of course, H.323 was not born in a vacuum. It's father, H.320 was developed in the late 1980's, introducing packetized media and call control over WAN networks. It's where most of the G.7xx codecs come from. H.320 has gateways, and admission controls, conversions between synchronous networks.... sound familiar at all?
- And of course, H.320 wasn't the first one either. How could it be? Px64 predated H.320 and was used as a major part of the spec, along with tight integration with Q.931. Yes, that SS7 spec. Anyone in Peabody at that time knew all about voice, video, packets, synchronous streams. I'm pretty sure that Regan was president.
- I remember listening to "geek of the week" in College around 1985-1986. Audio? Yup. Internet? Yup. Real time? Well, maybe not. I'll give you that one.
- Who could forget the ATT PicturePhone in 1970?
- World's Fair anyone?