| Very high speed digital subscriber line transceivers | |
| Status | In force |
|---|---|
| Year started | 2001 |
| Latest version | (11/15) November 2015 |
| Organization | ITU-T |
| Committee | ITU-T Study Group 15 |
| Related standards | G.993.1, G.993.2 |
| Domain | telecommunications |
| License | Freely available |
| Website | www |
Very high-speed digital subscriber line (VDSL)[1] and very high-speed digital subscriber line 2 (VDSL2)[2] are digital subscriber line (DSL) technologies providing data transmission faster than the earlier standards of asymmetric digital subscriber line (ADSL) G.992.1, G.992.3 (ADSL2) and G.992.5 (ADSL2+).
VDSL offers speeds of up to 52 Mbit/s downstream and 16 Mbit/s upstream,[3] over a single twisted pair of copper wires using the frequency band from 25 kHz to 12 MHz.[4] These rates mean that VDSL is capable of supporting applications such as high-definition television, as well as telephone services (voice over IP) and general Internet access, over a single connection. VDSL is deployed over existing wiring used for analog telephone service and lower-speed DSL connections. This standard was approved by the International Telecommunication Union (ITU) in November 2001.
Second-generation systems (VDSL2; ITU-T G.993.2 approved in February 2006)[5] use frequencies of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 metres (980 ft); performance degrades as the local loop attenuation increases.