During the first manned space flights, NASA used two radio-frequency (UHF or VHF) video links, one in each direction.
TV channels routinely use this type of videotelephony when reporting from distant locations.
By reducing the need to travel to bring people together, this technology also contributes to reductions in carbon emissions, thereby helping to reduce global warming.
The concept of videotelephony was first popularized in the late 1870s in both the United States and Europe, although the basic sciences to permit its very earliest trials would take nearly a half century to be discovered.
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 physicially manipulating objects).