Symmetric Digital Subscriber Line

Broadband Internet Glossary

Broadband Internet — Symmetric Digital Subscriber Line

Information on Symmetric Digital Subscriber Line

Symmetric Digital Subscriber Line allows broadband data services to be carried on conventional copper pair telephone cables. Symmetric Digital Subscriber Line is a single-pair alternative to HDSL, providing data rates (or speed) up to 1 Mbps duplex (i.e. for both upstream and downstream traffic).
     The term "symmetric" in ADSL refers to the difference in uplink and downlink capacities; the same capacity is provided for the downlink as for the uplink. This means that the same number of tones are allocated for downlink data as for uplink data.
     Symmetric Digital Subscriber Line is based on an adaptive, multi-tone modulation system. Each tone carries a part of either the uplink or the downlink bitstream. Because the bitstreams are split across a number of tones, the symbol rate on the link is much less than the bit rate.

Other topics in our resources on Broadband Internet related to Symmetric Digital Subscriber Line include: 

Symmetric Digital Subscriber Line Broadband (Symmetric Digital Subscriber Line Broadband)

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