The picturephone® system: Baseband video transmission on loops and short-haul trunks

Local Picturephone® service will be provided using present telephone cable facilities. Three cable pairs are required for each Picturephone call, one for audio and two for video transmission. Underground cables will be used extensively and aerial facilities to a limited extent. A cable equaliser will provide shaped gain to compensate for cable loss from 5 Hz to 1 MHz. This article discusses the plan for providing baseband video transmission on paired cable facilities, the cable equalizer design features, the important rules for engineering the video transmission system, and the maintenance features.