Essentially sending some form of video, from B W still frames to full motion, full color as well as audio over one of many transmission media to effect the experience of presence in the "other" place.
Quality varies greatly dependent mostly on bandwidth and the quality of the CODEC.
I have worked for two companies that make significant use of the technology.
Used mostly in business, but also used in Telecommunication Art See Electronic Cafe International, CIF
Related:
Sources:
http://www.ala.org/ala/pla/plapubs/technotes/videoteleconferencing.htm
http://www.videnet.gatech.edu/cookbook//
Last Updated 05.05.04