A telecommunications cable having a cable jacket defining an elongate cable core, a conductor assembly comprising four twisted pairs of conductors disposed along the core and parallel elongate distensions formed on an inner surface of the cable jacket. The distensions are spaced about an inner surface of the cable jacket and prevent the conductor assembly from coming into contact with the inner surface. The distensions can be 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. A separator spline has first and second elongate dividing strips having a substantially H shaped cross section and arranged side by side. The spline twists helicoidally along its length. The separator spline and the insulation surrounding the twisted pairs of conductors can be manufactured form a material having the same dielectric constant.