Videotelephony

Videotelephony (also known as videoconferencing or video call) is the use of audio and video for real-time communication between people.^[1]

Videophones are standalone devices for video calling. Other devices like smartphones and computers are now capable of video calling. Videoconferencing implies the use of videotelephony for groups.^[2] High-quality videoconferencing is used for telepresence, whose goal is to create the illusion that remote participants are in the same room. Videoconferencing has also been called visual collaboration and is a type of groupware.

The idea of videotelephony was concieved in the late 19th century, and became available to the public starting in the 1930s. Early demonstrations were installed at booths in post offices and shown at various world expositions. In 1970, AT&T launched the first commercial videotelephone system where anyone could subscribe and have the technology in their home or office. Image phones would exchange still images between units every few seconds over conventional telephone lines. The development of advanced video codecs, more powerful CPUs, and high-bandwidth Internet service in the late 1990s allowed videophones to provide high-quality low-cost color service between users almost any place in the world.

Applications of videotelephony include sign language transmission for deaf and speech-impaired people, distance education, telemedicine, and overcoming mobility issues. News media organizations have used videotelephony for broadcasting.^{[citation needed]}