Editing VDSL (section)

{{short description|Digital subscriber line technology}}
{{Infobox technology standard
|title= VDSL
|preview_date=
|long_name = Very high speed digital subscriber line transceivers
|preview =
|version_date = November 2015
|version = (11/15)
|year_started = 2001
|status = In force
|caption=
|image=
|organization = [[ITU-T]]
|committee = [[ITU-T Study Group 15]]
|license= Freely available
|domain= [[telecommunications]]
|abbreviation=
|related_standards= [[G.993.1]], [[G.993.2]]
|base_standards=
|website= {{URL|https://www.itu.int/rec/T-REC-G.993.2}}
}}

'''Very high-speed digital subscriber line''' ('''VDSL''')<ref name="VDSL-spec">{{cite web |title= ITU-T Recommendation G.993.1: Very high speed digital subscriber line transceivers (VDSL) |url= http://www.itu.int/rec/T-REC-G.993.1/en |access-date=24 July 2016}}</ref> and '''very high-speed digital subscriber line 2''' ('''VDSL2''')<ref name="VDSL2-spec">{{cite web |title=ITU-T Recommendation G.993.2: Very high speed digital subscriber line transceivers 2 (VDSL2) |url=http://www.itu.int/rec/T-REC-G.993.2/en |access-date=24 July 2016}}</ref> 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&nbsp;[[Mbit/s]] [[Downstream (networking)|downstream]] and 16&nbsp;Mbit/s [[Upstream (networking)|upstream]],<ref>{{cite web |url=http://computer.howstuffworks.com/vdsl2.htm |publisher=[[HowStuffWorks]] |title=VDSL Speed|date=21 May 2001 }}</ref> over a single [[twisted pair]] of [[copper wire]]s using the frequency band from 25&nbsp;[[kHz]] to 12&nbsp;MHz.<ref>{{cite web |url=http://www.itu.int/rec/T-REC-G.993.1-200406-I/en |publisher=ITU |title=G.993.1 (06/04)}}</ref> 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 [[Plain old telephone service|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)<ref name="vdsl2-press">{{Cite news |title= New ITU Standard Delivers 10x ADSL Speeds: Vendors applaud landmark agreement on VDSL2 |date= 27 May 2005 |work= News release |publisher= International Telecommunication Union |url= http://www.itu.int/newsroom/press_releases/2005/06.html |access-date= 22 September 2011 }}</ref> use frequencies of up to 30&nbsp;MHz to provide data rates exceeding 100&nbsp;Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about {{convert|300|m}}; performance degrades as the [[local loop]] [[attenuation]] increases.