The picturephone® system: Service standards

We describe in this paper the fundamental requirements of a visual telephone service. These lead to a basic physical configuration of the station equipment. The picture standards are chosen to provide the visual adjunct at no greater cost than is necessary to secure most of the possible enhancement of direct conversation. Transmission standards are established with the objective of limiting to an acceptable range the difference in quality between the image as viewed at the originating station and as received over the longest connection possible in the network.