The Development and Standardization of the Technologies
Audioconferencing, videoconferencing and data sharing technologies have been around for years. It is the real-time interoperability of these technologies using the desktop computer that is relatively new. The amount of data transfer required to maintain a video conference is astronomical and data compression techniques are used almost universally across all software packages designed for desktop/multimedia conferencing.
In the not so distant past, it would cost $40,000 to equip a room for videoconferencing. Currently, it costs less than $1,000 to equip a desktop computer with audio and video hardware and software technology.
Advances in desktop videoconferencing have come about due to increased standardization, growth of bandwidth on the world wide web, faster and cheaper desktop computers and better and less expensive video cameras.
Standardization
ITU-International Telecommunications Union
The ITU is an organization which promotes the establishment of operations and services of telecommunications for governmental agencies and private corporations. The Telecommunications Standards Sector of the ITU promotes world wide standards for audio, visual and data conferencing. A list of various standards are discussed below. The ITU-T T.120, H.320, H.323 and H.324 standards are the core standards for multimedia teleconferencing. Visit the ITU and IMTC websites for more information on these standards.
[T.120 Standard] supports audiographics and desktop conferencing between platforms. Standards-based systems support desktop conferencing, application and document sharing and collaboration. Traditionally, audiographics included facsimile, slow scan television, and 35mm slides."
The IMTC presented this overview of the H.320 Series of Standards:
"The H.320-series governs the basic videotelephony concepts of audio, video and graphical communications by specifying requirements for processing audio and video information, providing common formats for compatible audio/video inputs and outputs, and protocols that allow a multimedia terminal to utilize the communications links and synchronization of audio and video signals.
"Like the other multimedia teleconferencing standards, H.320 applies to multipoint and point-to-point sessions. The H.320 suite addresses videoconferencing over circuit switched services like ISDN or Switched-56. "
The IMTC presented this overview of the H.323 Series of Standards:
"The H.323 standard is an extension of H.320, which addresses videoconferencing over ISDN and other circuit switched networks and services. Since H.320 was ratified, in 1990, corporations have increasingly implemented Local Area Networks (LANs) and LAN gateways to the Wide Area Network (WAN). H.323 is a logical and necessary extension of the H.320 standard to include Corporate Intranets and packet-switched networks generally. Because it is based on the Real-Time Protocol (RTP/RTCP) from the IETF, H.323 can also be applied to video over the Internet.
"In common with the other ITU multimedia teleconferencing standard, H.323 applies to multipoint and point-to-point sessions."
The IMTC presented this overview of the H.324 Series of Standards:
"H.324 addresses and specifies a common method for sharing video, data, and voice simultaneously using high-speed (V.34) modem connections over a single analog (POTS) telephone line. It also specifies interoperability under these conditions, so that videophones, for example, based on H.324 will be able to connect and conduct a multimedia session."