How does a digital subscriber line (DSL) transmit data?

A digital subscriber line (DSL) transmits data over existing telephone lines using a technique that allows for high-frequency signals to be sent simultaneously with traditional voice calls. The technology takes advantage of the frequency spectrum of the standard copper telephone lines, which were initially designed for voice communication. By modulating data signals at higher frequencies than those used for voice, DSL enables users to access the internet without interrupting phone service.

This ability to utilize pre-existing infrastructure is a significant advantage of DSL, as it does not require new cables to be laid, thereby minimizing costs and installation disruptions. The effective separation of voice and data signals allows for simultaneous use, which is a cornerstone of how DSL operates.