How it Works

     DSL is a modem, not a line. DSL modems use twisted-pair bandwidth from 0 to about 120 kHz. They are being used today for so-called pair gain applications, in which DLS modems convert a single POTS (Plain Old Telephone Service) line to two POTS line by splitting the phone line into two frequency ranges: voice and data. Frequencies below 4 kHz are reserved for voice, and the range above is used for data. A device called splitter is needed to be installed on the phone line in order to separate the voice service from the data service. This makes it possible to use the line for phone calls and data network access at the same time.