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This technique was very expensive, though, and could not be used for applications such as telemedicine, distance education, and business meetings.
Only in the late 20th century with the advent of powerful video codecs combined with high-speed Internet broadband and ISDN service did videotelephony become a practical technology for regular use.
Simple analog videophone communication could be established as early as the invention of the television.
Such an antecedent usually consisted of two closed-circuit television systems connected via coax cable or radio.
Videoconferencing has also been called "visual collaboration" and is a type of groupware.
At the dawn of its commercial deployment from the 1950s through the 1990s, videotelephony also included "image phones" which would exchange still images between units every few seconds over conventional POTS-type telephone lines, essentially the same as slow scan TV systems.