Editing Digital subscriber line (section)

==DSL technologies==
{| class="wikitable"
|+DSL standards<ref>{{Cite web |title=DSL Technology Evolution |url=http://www.broadband-forum.org/downloads/About_DSL.pdf |url-status=dead |archive-url=https://web.archive.org/web/20090816085124/http://www.broadband-forum.org/downloads/About_DSL.pdf |archive-date=2009-08-16 |website=[[Broadband Forum]]}}</ref>
!Full name
!Abbreviation
!ITU-T standard
!Date
|-
| rowspan="3" |[[Asymmetric digital subscriber line]]
|ADSL
|[[G.992.1]] (G.dmt)
|1999
|-
|ADSL2
|[[G.992.3]] (G.dmt.bis)
|2002
|-
|ADSL2plus
|[[G.992.5]]
|2003
|-
|[[Asymmetric digital subscriber line]]-Reach Extended
|ADSL2-RE
|[[G.992.3]]
|2003
|-
|[[Single-pair high-speed digital subscriber line]]
|SHDSL
|[[G.991.2]]
|2003
|-
| rowspan="3" |[[Very-high-bit-rate digital subscriber line]]
|VDSL
|[[G.993.1]]
|2004
|-
|VDSL2 -12MHz long reach
|[[G.993.2]]
|2005
|-
|VDSL2 -30 MHz short reach
|[[G.993.2]]
|2005
|}
DSL technologies (sometimes collectively summarized as '''xDSL''') include:
*[[Symmetric digital subscriber line]] (SDSL), umbrella term for xDSL where the bitrate is equal in both directions.
**[[ISDN digital subscriber line]] (IDSL), ISDN-based technology that provides a bitrate equivalent to two ISDN bearer and one data channel, {{nowrap|144 kbit/s}} symmetric over one pair
**[[High-bit-rate digital subscriber line]] (HDSL), ITU-T G.991.1, the first DSL technology that used a higher frequency spectrum than ISDN, {{nowrap|1,544 kbit/s}} and {{nowrap|2,048 kbit/s}} symmetric services, either on 2 or 3 pairs at {{nowrap|784 kbit/s}} each, 2 pairs at {{nowrap|1,168 kbit/s}} each, or one pair at {{nowrap|2,320 kbit/s}}
**[[High-bit-rate digital subscriber line 2|High-bit-rate digital subscriber line 2/4]] (HDSL2, HDSL4), ANSI, {{nowrap|1,544 kbit/s}} symmetric over one pair (HDSL2) or two pairs (HDSL4)
**[[Symmetric digital subscriber line]] (SDSL), specific proprietary technology, up to {{nowrap|1,544 kbit/s}} symmetric over one pair
**[[Single-pair high-speed digital subscriber line]] (G.SHDSL), ITU-T G.991.2, standardized successor of HDSL and proprietary SDSL, up to {{nowrap|5,696 kbit/s}} per pair, up to four pairs
*[[Asymmetric digital subscriber line]] (ADSL), umbrella term for xDSL where the bitrate is greater in one direction than the other.
**[[ANSI T1.413 Issue 2]], up to {{nowrap|8 Mbit/s}} and {{nowrap|1 Mbit/s}}
**[[G.dmt]], ITU-T G.992.1, up to {{nowrap|10 Mbit/s}} and {{nowrap|1 Mbit/s}}
**[[G.lite]], ITU-T G.992.2, more noise and attenuation resistant than G.dmt, up to {{nowrap|1,536 kbit/s}} and {{nowrap|512 kbit/s}}
**[[Asymmetric digital subscriber line 2]] (ADSL2), ITU-T G.992.3, up to {{nowrap|12 Mbit/s}} and {{nowrap|3.5 Mbit/s}}
**[[Asymmetric digital subscriber line 2 plus]] (ADSL2+), ITU-T G.992.5, up to {{nowrap|24 Mbit/s}} and {{nowrap|3.5 Mbit/s}}
**[[Very-high-bit-rate digital subscriber line]] (VDSL), ITU-T G.993.1, up to {{nowrap|52 Mbit/s}} and {{nowrap|16 Mbit/s}}
**[[Very-high-bit-rate digital subscriber line 2]] (VDSL2), ITU-T G.993.2, an improved version of VDSL, compatible with ADSL2+, sum of both directions up to {{nowrap|200 Mbit/s}}.<ref>{{cite web | url=https://www.itu.int/rec/T-REC-G.993.2-201902-I/en | title=G.993.2 : Very high speed digital subscriber line transceivers 2 (VDSL2) }}</ref> [[G.vector]] crosstalk cancelling feature (ITU-T G.993.5) can be used to increase range at a given bitrate, e.g. {{nowrap|100 Mbit/s}} at up to 500 meters.<ref>{{Cite journal |last1=Oksman |first1=Vladimir |last2=Schenk |first2=Heinrich |last3=Clausen |first3=Axel |display-authors=1 |date=October 2010 |title=The ITU-T's New G.vector Standard Proliferates 100 Mb/s DSL |journal=IEEE Communications Magazine |volume=48 |issue=10 |pages=140–148 |doi=10.1109/MCOM.2010.5594689 |url=http://www.ericsson.com/res/thecompany/docs/journal_conference_papers/broadband_and_transport/itu-ts_new_g_vector_standard_proliferates_100mbs_dsl.pdf |access-date=2013-12-12 |archive-date=2018-12-27 |archive-url=https://web.archive.org/web/20181227171441/https://www.ericsson.com/res/thecompany/docs/journal_conference_papers/broadband_and_transport/itu-ts_new_g_vector_standard_proliferates_100mbs_dsl.pdf }}</ref>
**[[G.fast]], ITU-T G.9700 and G.9701,<ref name="ITUT-PR-2013-12-11">{{cite web |url=http://www.itu.int/net/pressoffice/press_releases/2013/74.aspx |title=New ITU broadband standard fast-tracks route to {{nowrap|1 Gbit/s}} |publisher=ITU-T |date=2013-12-11 |access-date=2014-02-13}}</ref> up to approximately {{nowrap|1 Gbit/s}} aggregate uplink and downlink at 100m.<ref name="alu">{{cite web |url=http://www2.alcatel-lucent.com/techzine/the-numbers-are-in-vectoring-2-0-makes-g-fast-faster/ |title=The Numbers are in: Vectoring 2.0 Makes G.fast Faster |last1=Spruyt |first1=Paul |last2=Vanhastel |first2=Stefaan |publisher=Alcatel Lucent |work=TechZine |date=2013-07-04 |access-date=2014-02-13 |archive-url=https://web.archive.org/web/20140802091321/http://www2.alcatel-lucent.com/techzine/the-numbers-are-in-vectoring-2-0-makes-g-fast-faster/ |archive-date=2014-08-02 |url-status=dead }}</ref> Approved in December 2014, deployments planned for 2016.<ref name="g9701">{{cite web |url=http://www.itu.int/net/pressoffice/press_releases/2014/70.aspx |title=G.fast broadband standard approved and on the market |publisher=ITU-T |date=2014-12-05 |access-date=2014-12-07}}</ref><ref name="Alu-ONT">{{cite web |url=http://www.lightwaveonline.com/articles/2014/10/gfast-ont-available-early-next-year-says-alcatel-lucent.html |title=G.fast ONT available early next year says Alcatel-Lucent |last=Hardy |first=Stephen |date=2014-10-22 |access-date=2014-10-23 |publisher=lightwaveonline.com}}</ref>
**XG-FAST, allows for up to 10&nbsp;Gbps on copper twisted pair lines, but only for lengths up to 30 meters. Real-world tests have shown 8&nbsp;Gbps on 30-meter long twisted pair lines.<ref>{{Cite web|url=https://arstechnica.com/information-technology/2016/10/xg-fast-dsl-does-10gbps-over-telephone-lines/|title=XG.fast DSL does 10Gbps over telephone lines|first=Sebastian|last=Anthony|date=October 18, 2016|website=Ars Technica}}</ref><ref>{{Cite journal|url=https://ieeexplore.ieee.org/document/7355589|title=XG-fast: the 5th generation broadband|first1=Werner|last1=Coomans|first2=Rodrigo B.|last2=Moraes|first3=Koen|last3=Hooghe|first4=Alex|last4=Duque|first5=Joe|last5=Galaro|first6=Michael|last6=Timmers|first7=Adriaan J.|last7=van Wijngaarden|first8=Mamoun|last8=Guenach|first9=Jochen|last9=Maes|date=December 5, 2015|journal=IEEE Communications Magazine|volume=53|issue=12|pages=83–88|via=IEEE Xplore|doi=10.1109/MCOM.2015.7355589|s2cid=33169617 |url-access=subscription}}</ref><ref>{{Cite web|url=https://www.zdnet.com/article/nbn-attains-8gbps-speeds-over-copper-in-xg-fast-trial-with-nokia/|title=NBN attains 8Gbps speeds over copper in XG-FAST trial with Nokia|website=ZDNET}}</ref>
*[[Bonded DSL Rings]] (DSL Rings), a shared ring topology at {{nowrap|400 Mbit/s}}
*[[Cable/DSL gateway]]
*[[Etherloop]] Ethernet local loop
*[[High-speed voice and data link]]
*[[Rate-Adaptive Digital Subscriber Line]] (RADSL), designed to increase range and noise tolerance by sacrificing upstream speed
*[[Uni-DSL]] (Uni digital subscriber line or UDSL), technology developed by Texas Instruments, backward compatible with all DMT standards
*[[Hybrid Access Networks]] combine existing xDSL deployments with a wireless network such as [[LTE (telecommunication)|LTE]] to increase bandwidth and quality of experience by balancing the traffic over the two access networks.<ref name="BBF-TR348">{{cite web |url=https://www.broadband-forum.org/technical/download/TR-348.pdf |archive-url=https://ghostarchive.org/archive/20221009/https://www.broadband-forum.org/technical/download/TR-348.pdf |archive-date=2022-10-09 |url-status=live |title=TR-348 Hybrid Access Broadband Network Architecture|last=Broadband Forum|date=2016-07-01|access-date=2018-07-01}}</ref>

The line-length limitations from telephone exchange to subscriber impose severe limits on data transmission rates. Technologies such as [[VDSL]] provide very high-speed but short-range links. VDSL is used as a method of delivering [[Triple play (telecommunications)|triple play]] services (typically implemented in [[fiber to the curb]] network architectures).

Terabit DSL, is a technology that proposes the use of the space between the dielectrics (insulators) on copper twisted pair lines in telephone cables, as waveguides for 300 GHz signals that can offer speeds of up to 1 terabit per second at distances of up to 100 meters, 100 gigabits per second for 300 meters, and 10 gigabits per second for 500 meters.<ref>{{Cite web|url=https://www.theregister.com/2017/05/10/dsl_inventors_latest_science_project_terabit_speeds_over_copper/|title=DSL inventor's latest science project: terabit speeds over copper|first=Richard|last=Chirgwin|website=www.theregister.com}}</ref><ref>{{Cite journal|url=https://ieeexplore.ieee.org/document/8539030|title=Terabit DSLs|first1=John M.|last1=Cioffi|first2=Kenneth J.|last2=Kerpez|first3=Chan Soo|last3=Hwang|first4=Ioannis|last4=Kanellakopoulos|date=November 5, 2018|journal=IEEE Communications Magazine|volume=56|issue=11|pages=152–159|via=IEEE Xplore|doi=10.1109/MCOM.2018.1800597|s2cid=53927909 |url-access=subscription}}</ref> The first experiment for this was carried out with copper lines that were parallel to each other, and not twisted, inside a metal pipe meant to simulate the metal armoring in large [[telephone cable]]s.<ref>{{Cite web|url=https://spectrum.ieee.org/terabit-second|title=Terabits-Per-Second Data Rates Achieved at Short Range|website=ieeespectrum}}</ref><ref>{{Cite journal|title=A wire waveguide channel for terabit-per-second links|first1=Rabi|last1=Shrestha|first2=Kenneth|last2=Kerpez|first3=Chan Soo|last3=Hwang|first4=Mehdi|last4=Mohseni|first5=John M.|last5=Cioffi|first6=Daniel M.|last6=Mittleman|date=March 30, 2020|journal=Applied Physics Letters|volume=116|issue=13|pages=131102|doi=10.1063/1.5143699|bibcode=2020ApPhL.116m1102S |s2cid=216327606 |doi-access=free}}</ref>