Multi-rate symmetric digital subscriber line
Multi-rate symmetric DSL (MSDSL or MDSL) is a proprietary, non-standardized symmetric digital subscriber line technology with a maximum distance of 29,000 feet (8,800 m). It is capable of multiple transfer rates, as set by the Internet service provider, typically based on the service and/or price.
Source: Wikipedia — Multi-rate symmetric digital subscriber line (CC BY-SA 4.0)