Symmetric Digital Subscriber Line (SDSL)

A symmetric high-speed digital network connection, usually between a home or small business and a telecommunications vendor, providing an always-up direct connection to an Internet Service Provider (ISP) . The upstream (from the user to the ISP) and downstream (from the ISP to the user) speeds are identical. See also Asymmetric Digital Subscriber Line (ADSL) , Digital Subscriber Line (DSL) .