History of videotelephony

telephonoscope

France in XXI Century. Correspondance cinema

AT&T Picturephone Advertisement 1970

AT&T Picturephone - upper RH oblique view

AT&T Picturephone Mod II - right side view with its cover removed

History of Videotelephony

The history of videotelephony encompasses the historical development of several technologies which enable the use of live video in addition to voice telecommunications. The concept of videotelephony was first popularized in the early 20th century, and has since evolved from simple video calls to complex applications in telemedicine, tele-education, and teleconference systems.

Early Developments

The idea of transmitting images along with sound over a distance has its roots in the late 19th and early 20th centuries. The first conceptual designs and experimental systems for what would later become known as videotelephony were developed shortly after the invention of the telephone and the telegraph. One of the earliest known proposals for a videophone was made by the German inventor Augustin Mouchot in 1878, who envisioned a system that used the sun's energy to transmit images over telegraph wires.

In the 1920s and 1930s, the first practical videophone systems were developed. These early systems, such as the German Reichspost's public video telephone service launched in 1936, were based on mechanical television technology and had very limited image quality. Despite these limitations, they marked the first step towards the realization of videotelephony.

Post-World War II Developments

The development of electronic television technology after World War II significantly advanced the videotelephony field. In the 1960s, AT&T's Bell Labs introduced the Picturephone at the 1964 New York World's Fair. The Picturephone service was a pioneering effort in commercial videotelephony, allowing callers to see each other on small video screens. However, due to high costs and limited infrastructure, the service was not widely adopted.

Digital Revolution

The advent of digital technology in the late 20th century was a turning point for videotelephony. Digital compression techniques, such as those developed by the Moving Picture Experts Group (MPEG), made it possible to transmit video over the limited bandwidth of early computer networks and eventually the Internet. This led to the development of video conferencing systems for corporate use in the 1980s and 1990s, as well as the introduction of personal computer-based videotelephony software like Skype in the early 2000s.

The Internet Era

The proliferation of broadband Internet access and improvements in video compression algorithms have greatly expanded the possibilities for videotelephony. Today, videotelephony is widely used in various fields, including telemedicine, where doctors can consult with patients remotely, and in education, where teachers can conduct classes with students around the world. The COVID-19 pandemic further accelerated the adoption of videotelephony, making video calls a standard for personal and professional communication.

Future Directions

The future of videotelephony includes the integration of augmented reality (AR) and virtual reality (VR) technologies, which promise to make remote communication even more immersive. Developments in 5G technology are also expected to improve the quality and reliability of video calls, enabling more sophisticated applications of videotelephony in everyday life.