Digital Subscriber Line (DSL)
DSL technologies use unused frequencies available in standard telephone wire for data transmission. Voice communications are carried on only 4 kilohertz of the available frequency of copper wires. This leaves the rest of the frequencies on copper cabling available for data communications.DSL is the most cost-effective way to get high-speed bandwidth to the Internet.
There are many types of DSL, but the most common are ADSL and SDSL. Asymmetric (ADSL) has download speeds much higher than upload speeds; this is the most common and effective DSL for residential use. Symmetric (SDSL) has download speeds and upload speeds at the same rate per second; this is more common for business use, because of the large transfers of outgoing data.
