Digital Subscriber Line (DSL) is a family of technologies that transports data over existing twisted-pair copper wire. DSL uses frequencies that are beyond the upper list used by POTS (plain old telephone service) to deliver broadband applications, such as multimedia and video, over the local loop (or last mile) that connects the telephone company's central office to customer sites.

Based on the International Telecommunications Union (ITU) G.991.2 global industry standard, symmetric high-speed digital subscriber line (SHDSL) delivers symmetrical data rates from 192 up to 2.3 Mbps on a single wire pair. It transports many types of signals, such as T1, E1, ISDN, ATM, and IP. In addition, the G.SHDSL signal has a greater distance reach from the central office than ADSL and proprietary SDSL connections

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