Videotelephony, also known as video chat, videoconferencing, video calling, or telepresence, is the use of audio and video for simultaneous two-way communication.
A telepresence system in 2007
Videotelephony predicted to be in use by 2000, as envisioned in 1910 (artist's conception)
Videotelephone booth, 1922
Gregorio Y. Zara was a Filipino engineer and physicist best remembered for inventing the first two-way video telephone.
Commonly used modalities include webcams, videoconferencing, phone lines, videophones and webpages containing rich Internet applications. The visual nature of telerehabilitation technology limits the