A telecommunications cable and separator spline. In one example the cable includes a cable jacket defining an elongate cable core, a conductor assembly including four twisted pairs of conductors disposed along the core and a plurality of parallel elongate localized and like distensions in an inner surface of the cable jacket. The distensions are substantially evenly spaced about an inner surface of the cable jacket. In one example, the distensions are the result of a series of filler elements placed between the cable jacket and the cable core and which wind helicoidally along and about the cable core. The separator spline includes first and second elongate dividing strips having a substantially H shaped cross section and arranged side by side, and twists helicoidally along its length. In one example the separator spline and the insulation surrounding the twisted pairs of conductors is manufactured form a material having the same dielectric constant.