G.992.3
| Asymmetric digital subscriber line transceivers 2 (ADSL2) | |
| Status | In force |
|---|---|
| Year started | 2003 |
| Latest version | (10/12) October 2012 |
| Organization | ITU-T |
| Related standards | G.992.5,G.992.3 Annex J |
| Domain | telecommunications |
| License | Freely available |
| Website | https://www.itu.int/rec/T-REC-G.992.3/ |
ITU G.992.3is an ITU (International Telecommunication Union) standard, also referred to asADSL2orG.dmt.bis.It optionally extends the capability of basicADSLin data rates to 12Mbit/sdownstream and, depending onAnnex version,up to 3.5 Mbit/s upstream (with a mandatory capability of ADSL2 transceivers of 8 Mbit/s downstream and 800 kbit/s upstream).[1]ADSL2 uses the same bandwidth as ADSL but achieves higher throughput via improved modulation techniques. Actual speeds may decrease depending on line quality; usually the most significant factor in line quality is the distance from theDSLAMto the customer's equipment.
Annex versions
[edit]ADSL2has multiple modes forDSLproviders to offer services for different needs. Below is a list of available features based onADSL2specs from theITUstandards.
| Annex version | Spec | Description |
|---|---|---|
| A | xDSLoverPOTS | xDSLservice functioning overplain old telephone service. |
| B | xDSLoverISDN | xDSLServices running overIntegrated Services Digital Network. |
| C | xDSLinISDN | xDSLSystem operating in the same cable asISDNas defined inITU-TRec.G.961 Appendix III (Currently[as of?]not implemented) |
| D | ATU-CandATU-Rstate diagrams | See Annex D/G.992.3 |
| E | POTSandISDN-BAsplitters | See Annex E/G.992.3. For operation according to Annexes A, B and I, the G.992.3 requirements applying over a frequency band up to 1104 kHz shall be met over a frequency band up to 2208 kHz. |
| F | ATU-xperformance requirements for region A (North America) | F.1 Performance requirements for operation ofADSLoverPOTS(Annex A) F.2 Performance requirements for operation of All Digital ModeADSL(Annex I) F.3 Performance requirements for operation ofADSLoverPOTSwith extended upstream bandwidth (Annex L) |
| G | ATU-xperformance requirements for region B (Europe) | G.1 Performance requirements for operation ofADSLoverPOTS(Annex A) G.2 Performance requirements for operation ofADSLoverISDN(Annex B) G.3 Performance requirements for operation of All Digital ModeADSL(Annex I) G.4 Performance requirements for operation of All Digital ModeADSL(Annex J) G.5 Performance requirements for operation ofADSLoverPOTS,with extended upstream bandwidth (Annex L) |
| I | All Digital modeADSLwith improved spectral compatibility withADSLoverPOTS | ExtendingADSLband to use the voice frequency range, 32 upstream tones for an additional 256kbit/s upstream data rate overPOTSlines. |
| J | All Digital modeADSLwith improved spectral compatibility withADSLoverISDN | ExtendingADSLband to use the voice frequency range, 64 upstream tones for an additional 256 kbit/s upstream data rate overISDNLines. |
| L | Reach Extended | Increases the range of theDSLservice enabling the link to work at a distance of 7 kilometres (23,000 ft) |
| M | Increased Upload speeds | Upstream/downstream frequency split has been shifted from 138 kHz up to 276 kHz, allowing maximum upstream bandwidth to be increased from 1.4 Mbit/s to 3.3 Mbit/s. |
See also
[edit]References
[edit]- ^"G.992.3: Asymmetric digital subscriber line transceivers 2 (ADSL2)".www.itu.int.Archivedfrom the original on 2021-04-26.Retrieved2021-04-26.
External links
[edit]- ITU-T Recommendation G.992.3:Asymmetric digital subscriber line transceivers 2 (ADSL2)