xDSL

The Asymmetrical Digital Subscriber Line (ADSL) and Very High Speed Digital Subscriber Line (VDSL) are transmission methods for high-speed data transmissions over regular telephone lines.

With ADSL and ADSL2+, transmissions (downstream) of up to 24 Mbps can be implemented over normal telephone lines; for bidirectional transmission there is a second frequency band with transmission speeds of up to 3.5 Mbps (upstream) - hence the name "asymmetric". As an example, the ADSL-over-ISDN infrastructure operated in Germany supports maximum speeds of 16 Mbps (downstream) and 1125 kbps (upstream).

VDSL is a DSL technology that delivers far higher data rates over normal phone lines than, for example, ADSL or ADSL2+.