Terabits-Per-Second Data Rates Achieved at Short Range

Using the same kind of techniques that allow DSL to transmit high-speed Internet over regular phone lines, scientists have transmitted signals at 10 terabits per second or more over short distances, significantly faster than other telecommunications technologies, a new study finds.

Digital subscriber line (DSL) modems delivered the first taste of high-speed Internet access to many users. They make use of the fact that existing regular telephone lines are capable of handling a much greater bandwidth than is needed just for voice. DSL systems leverage that extra bandwidth to send multiple signals in parallel across many frequencies.

Using megahertz frequencies, current DSL technologies can achieve downstream transmission rates of up to 100 megabits per second at a range of 500 meters, and more than 1 gigabit per second at shorter distances. (DSL signal quality often decreases over distance because of the limitations of phone lines; telephone companies can boost voice signals with small amplifiers called loading coils, but these do not work for DSL signals.)