Ericsson has successfully demonstrated data-transfer speeds of more than 500 megabits per second over copper, the communications company said Monday. The data-transfer rates were achieved using a version of digital subscriber line (DSL) technology called “vectorized” VDSL2, Ericsson said in a statement. The technology, also called “crosstalk cancellation,” provides the high transmission rates through a twisted pair of copper cables by reducing the noise coming from other pairs in the same cable bundle.