Picturephone arrived in the early 1970s. 1ESS switch was already going into service and provided a more sophisticated basis for advanced services, but was not yet as widely available, so 5XB was designated as the switching vehicle. Every Picturephone line has six wires: the old talking pair plus a video transmission pair and a video receiving pair. A new wideband switching fabric was designed using a 6-wire version of Type B crossbar switches, two of the wires being grounded, thus diminishing crosstalk for the two video pairs. When completing a Picturephone call, the completing marker first picked the line or trunk to which the audio portion of the call would be completed, and then set up both the audio switches and the video ones. Wideband remote switches (WBRS) were installed in smaller exchanges, as video concentrators for lines that were beyond video range from a larger exchange that had been given the Picturephone feature.