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Which connections can be used for videoconference?
Videoconferencing is not currently a "plug-and-play" technology. Videoconferencing actually began over a decade ago with the introduction of expensive group conferencing systems designed to send and receive compressed audio and video over network connections that could guarantee a dedicated rate of transmission and predictable service (i.e., point-to-point T1 or fractional T1 communication links, switched connections using ISDN, or ATM). Standards surrounding how the audio and video would be compressed, how the endpoints would communicate with each other (i.e., initiating/terminating calls, negotiating audio/video compatibility, indicating error conditions during a call), and how the video streams would travel over the network eventually evolved but systems were not fully interoperable at the start. Still, evolution persisted and useful videoconferencing did finally emerge. Arguably the most popular and extensible early compressed videoconferencing was enabled via the ITU (International Telecommunications Union) standard called H.320. However, even with H.320, videoconferencing remained largely restricted to a) those who could afford the technology and network connections to establish meeting rooms, and b) those who were able to travel to a videoconference enabled meeting location.
As time has gone on, the above restrictions have lessened. The technology itself for conducting videoconferencing has become less expensive, more flexible, and now includes options for desktop videoconferencing as well as group videoconferencing. More ubiquitous network types, particularly TCP/IP as used on the Internet, are commonly used to provide less expensive and more flexible connections. In conjunction with this, a new ITU standard has emerged for supporting audio/videoconferencing over IP. This new standard, H.323, was first approved by the ITU in 1996 And has evolved through several additional versions since then and been implemented in a wide variety of commercially available products.
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