DSL Internet is Internet that is accessed over telephone lines and can also be called digital subscriber lines. The same lines that are used for home phones are used to deliver the signal for the Internet.
The signal for the Internet is run at a much higher frequency to prevent it from interfering with telephone calls. There is a special filter used to keep the Internet frequencies from interfering with the phone calls. The DSL can come in two types, symmetric and asymmetric. The symmetric DSL lines allow an even flow of data in and out of the system. Asymmetric, which provides a wider section of the lines for downloads, is used more often since most users do more downloads than uploads.