ADSL - Asymmetric Digital Subscriber Line
Asymmetric digital subscriber line is a type of DSL technology, that enables faster transmission of data over the existing copper line, traditionally used for voice communication. It provides high data rate by utilizing the unused frequency band of voice channels.
The splitter, or DSL filter used at both the ends allows single telephone connection to be used for both ADSL service and voice communication. In ADSL technology, the downstream data rate is much higher than the upstream, that's why the name asymmetric. This very reason makes this technology suitable for home users.
The theoretical data rate of ADSL is 13.4 Mbps for downstream data transfer and 1.544 Mbps for upstream. But, the actual data rate is very low, as the majority of channels are not considered due to the effect of noise in them.