Attempts at using normal telephony networks to transmit slow-scan video, such as the first systems developed by AT&T Corporation, first researched in the 1950s, failed mostly due to the poor picture quality and the lack of efficient video compression techniques.The greater 1 MHz bandwidth and 6 Mbit/s bit rate of the AT&T Picturephone in the 1970s also did not achieve commercial success, mostly due to its high cost, but also due to a lack of network effect — with only a few hundred Picturephones in the world, users had extremely few contacts they could actually call to, and interoperability with other videophone systems would not exist for decades.The news media were to become regular users of mobile links to satellites using specially equipped trucks, and much later via special satellite videophones in a briefcase.This technique was very expensive, though, and could not be used for applications such as telemedicine, distance education, and business meetings.Although not as widely used in everyday communications as audio-only and text communication, useful applications include sign language transmission for deaf and speech-impaired people, distance education, telemedicine, and overcoming mobility issues.It is also used in commercial and corporate settings to facilitate meetings and conferences, typically between parties that already have established relationships.Telepresence may refer either to a high-quality videotelephony system (where the goal is to create the illusion that remote participants are in the same room) or to meetup technology which goes beyond video into robotics (such as moving around the room or physically manipulating objects).
However video technology was to be deployed in analog television broadcasting long before it could become practical—or popular—for videophones.
Videotelephony developed in parallel with conventional voice telephone systems from the mid-to-late 20th century.
Very expensive videoconferencing systems rapidly evolved throughout the 1980s and 1990s from proprietary equipment, software and network requirements to standards-based technologies that were available for anyone to purchase at a reasonable cost.
During this time, there was also research into other forms of digital video and audio communication.
Many of these technologies, such as the Media space, are not as widely used today as videoconferencing but were still an important area of research.