Videoconferencing 

Teleconferencing or videoconferencing is an electronic conference using video. It:

1.        Allows information to be shared among colleagues around the world at the same time

2.        Gives colleagues the ability to share visual aids

3.        Promotes unity and participation in group meetings and discussions

4.        Saves on travel (and consequently money) budgets

5.       Lower environmental impact than physical travel - air travel, in particular, is a major source of carbon dioxideemissions thus contributing to global warming and climate change

 Videoconferencing networks can be implemented using one of two transmission technologies: satellite or terrestrial. Within each of these networks there are two categories: multi-point and point-to-point.

1.        Multi-point - the exchange of audio and video information between more than two points. It is further categorised into two sub-categories: broadcast and interactive. The broadcast is the conveyance of audio and video information from a transmitting site to multiple receiving sites without interaction. However, this one way radio often included return audio for Q&A via telephone lines. The interactive multi-point conference is similar to the broadcast with the addition of the capability of interaction (audio and/or video) between all the sites involved in the conference.

2.        Point-to-point - the exchange of audio and video information between two points in a full duplex, interactive manner.

Therefore the current types of conferencing available are:

1.        CODEC / ISDN Public Rooms. Terrestrial, multi-point, interactive conferencing. This uses a monitor, small camera and an integration box, that allows the participants to send and receive audio and video via ISDN lines. The video signal still falls short of the “full motion video” experienced by satellite transmission technologies and there is the occasional un-sync’d audio and video. It only allows a meeting among a few locations with a few people at each location.

2.        Desktop conferencing and webcasting. Terrestrial, multi-point, broadcast conferencing. These are both computer forms of communication. Desktop conferencing is a targeted communication that can be done over the Internet or Intranet. Webcasting uses the Internet and is made available to participants by means of website, and so is a less secure form of communication. It allows the participants to view from their desk, although it is mainly one-way communication. The content of the meeting must be quite simple, as the video produced is slow, but it does allow the event to be saved for viewing after the live event.

3.        Multi-point or point-to-point satellite. This allows “real-time” video with up to 34 frames per second. It allows meetings with medium to large groups in remote locations.

Differences between the types of conferencing only appear when you compare multi-point satellite and multi-point terrestrial videoconferencing, as detailed in the table below (adapted from http://www.qpcomm.com).

 Sources and further reading

http://www.qpcomm.com

http://www.satellite-commsys.com/webcast.htm