DSL technologies
	Standard
ADSL	ANSI T1.413 Issue 2 ITU G.992.1 (G.DMT) ITU G.992.2 (G.Lite)
ADSL2	ITU G.992.3/4 ITU G.992.3 Annex J ITU G.992.3 Annex L
ADSL2+	ITU G.992.5 ITU G.992.5 Annex M
HDSL	ITU G.991.1
HDSL2
IDSL
MSDSL
PDSL
RADSL
SDSL
SHDSL	ITU G.991.2
UDSL
VDSL	ITU G.993.1
VDSL2	ITU G.993.2

Annex J is a specification in ITU-T recommendations G.992.3 and G.992.5 for all digital mode ADSL with improved spectral compatibility with ADSL over ISDN, which means that it is a type of naked DSL which will not disturb existing Annex B ADSL services in the same cable binder.

This specification has the same upstream/downstream frequency split of 276 kHz as Annex B, but does not have lower frequency limit of 138 kHz, allowing upstream bandwidth to be increased from 1 Mbit/s to 3.5 Mbit/s. This is similar to Annex M, but Annex J can not have POTS on the same line.

[edit] External links

• ITU-T Recommendation G.992.3: Asymmetric digital subscriber line transceivers 2 (ADSL2)
• ITU-T Recommendation G.992.5: Asymmetric Digital SubscriberLine (ADSL) transceivers - Extended bandwidth ADSL2 (ADSL2+)

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