What is SDSL?

Another variation of DSL to be widely used is SDSL or Symmetric DSL (digital subscriber line). The main characteristic of SDSL is that it is symmetrical, meaning an equal amount of bandwidth is available in both directions. In other words, downloading has the exact same data capacity as uploading. This option is ideal for small- and medium-sized businesses that have an equal need to download and upload data over the Internet.

A typical use of SDSL would be a company running a web server at their office (web servers require upstream bandwidth so you would need the upstream capacity as much as the downstream capacity). SDSL can carry about as much data on a single wire of twisted-pair as can be carried on a T1 line.