Symmetric Digital Subscriber Line (SDSL) is a Digital Subscriber Line (DSL) variant with E1-like data rates (72 to 2320 kbit/s). It runs over one pair of copper wires, with a maximum range of about 3 kilometers. The main difference between ADSL and SDSL is that SDSL has the same upstream data transfer rate as downstream (symmetrical), whereas ADSL always has smaller upstream bandwidth (asymmetrical). A typical DSL Modem Digital Subscriber Line, or DSL, is a family of technologies that provide digital data transmission over the wires of a local telephone network. ... Two Network Interface Units, one with a single card, the other with two In telecommunications, T-carrier is the generic designator for any of several digitally multiplexed telecommunications carrier systems originally developed by Bell Labs and used in North America and Japan. ... Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional modem can provide. ... Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... Symmetry is a characteristic of geometrical shapes, equations and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ...

SDSL was never properly standardised until G.SHDSL was standardised by ITU. SDSL is often confused with G.SHDSL and unfortunately, in Europe G.SHDSL was standardized by ETSI using the name 'SDSL'. This ETSI variant is compatible with the ITU-T G.SHDSL standardized regional variant for Europe. Symmetric high-speed digital subscriber line (SHDSL) is a telecommunications technology for Digital Subscriber Line (DSL) subscriber lines. ... Monument in Bern, Switzerland. ... World map showing Europe Political map Europe is one of the seven continents of Earth which, in this case, is more a cultural and political distinction than a physiographic one, leading to various perspectives about Europes borders. ... The European Telecommunications Standards Institute (ETSI) is a standardization organization of the telecommunications industry (equipment makers and network operators) in Europe, with worldwide projection. ... Monument in Bern, Switzerland. ...

Equipment touting SDSL support is usually proprietary equipment which only speaks to SDSL equipment from the same vendor, or to SDSL equipment from other vendors that use the same DSL chipset. Most new installations use G.SHDSL equipment instead of SDSL. A chipset is a group of integrated circuits (chips) that are designed to work together, and are usually marketed as a single product. ...

See also

• G. Symmetric High-speed Digital Subscriber Line (G.SHDSL)
• Digital Subscriber Line (DSL)
• Asymmetric Digital Subscriber Line (ADSL)
• ISDN