SDSL (Single-Line Digital
Subscriber Line)

SDSL can be known as Single-line Digital Subscriber Line which is HDSL over a single telephone line. What you need to remember is this particular name, Single-line Digital Subscriber Line has not yet been adopted by a standards group yet, so it may not stick as a name. It is also very important to remember that SDSL operates over POTS and would be suitable for symmetric services to premises of individual customers.