Im getting confused now...... I thought BT used Annex B.
As burakkucat enlightened me
I would just like to make a comment regarding the "Annex" setting.
As I am sure you appreciate, there are two annexes -- one for the physical infrastructure and one for the VDSL2 mode band plans. The UK uses Annex A for the physical infrastructure (xDSL over POTS) and uses Annex B for the VDSL2 mode band plans, as deployed by Beattie.
They are two separate, distinct and unconnected annexes -- which can be a snare for the unwary (e.g. support agents).
So as I now understand it, from the VDSL2 spec,
https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.993.2-201112-I!!PDF-E&type=itemsThe UK used a Europe bandplan as defined in
ANNEX B of the VSDL2 spec.
There is just one bandplan in Annex A and it's for the USA.
However these bandplans have variants for whether they are over POTS or ISDN. The spec says:
"Different variants are defined for band plans 997, 998, 998E17, 998E30, 998ADE17 and 998ADE30 to accommodate different underlying services (POTS and ISDN), and different US0 bandwidths."
Now Annex A of
some physical infrastructure spec is xDSL over POTS, and Annex B is xDSL over ISDN.
So openreach uses an
ANNEX B bandplan from the VDSL2 spec (G.993.2) over an Annex A (from
some spec) physical infrastructure.
[
some is probably G.992.1 :
https://www.itu.int/rec/dologin_pub.asp?lang=e&id=T-REC-G.992.1-199907-I!!PDF-E&type=items ]
I now believe the ASUS "DSL Setting" -> "Annex Mode" setting to refers to the physical infrastructure not the G.993.2 annex. It can justifiably be in the DSL settings as it determines which variant of the the bandplan is used.