The recent growth of the Internet has increased the demand for additional bandwidth. Digital subscriber line (xDSL) technology meets the demand by providing higher bandwidth data service over existing twisted pair telephone lines. xDSL technology achieves higher data transmission rates by taking advantage of unused frequencies, which are significantly higher than voice band frequencies, on existing twisted pair lines.
xDSL technology, however, is limited because signals cannot be transmitted over long distances without losing signal strength. Due to this limitation, subscribers located closer to the data service provider typically achieve higher data transmission rates than subscribers located further away. Data transmission rates to subscribers located a short distance from the data service provider, however, can also be affected by other conditions, such as noise on the digital signals or intermodulation within the data transmission bands.