I am confused since you appear to say that Annex B Plan A is the same as band plan 997, so is the above quote from the document wrong?
Sorry, I accidentally transposed those two. It should have read G998 = Annex B Plan A; G997 = Annex B Plan B
The Openreach VDSL2 Profile 8c service uses Annex B Band Plan G997 (aka plan B) - Variant #1,
The Openreach VDSL2 Profile 17a service uses Annex B Band Plan G998 (aka plan A) - Variant #1.
The following is reported by a Huawei HG612 on a Profile 17a VDSL2 service provided by BT Openreach.
1 23 45 67 89 1011 1213 1415 1617 1819 2021
# xdslcmd info --show xdslcmd: ADSL driver and PHY statusStatus: Showtime Retrain Reason: 0Max: Upstream rate = 24622 Kbps, Downstream rate = 67492 Kbps Path: 0, Upstream rate = 10000 Kbps, Downstream rate = 39998 Kbps Link Power State: L0Mode: VDSL2 Annex B VDSL2 Profile: Profile 17aTPS-TC: PTM Mode Trellis: U:ON /D:ONLine Status: No Defect Training Status: Showtime.... # xdslcmd info --pbParamsxdslcmd: ADSL driver and PHY status Medley Phase (Final) Band Plan US: (0,95) (868,1207) (1972,2783)DS: (32,859) (1216,1963) (2792,3939)
Those tone numbers can again be multiplied by the carrier spacing (4.3125kHz) to find the band-edge frequencies:
Huawei HG612 (on Profile 17a):
f1 = 32 x 4.3125 = 138 kHz
f2 = 868 x 4.3125 = 3.75 MHz
f3 = 1216 x 4.3125 = 5.20 MHz
f4 = 1972 x 4.3125 = 8.50 MHz
f5 = 2792 x 4.3125 = 12.00 MHz
And those are G998 Band Plan Variant #1 frequencies, which are identical to those in the Annex A band plan for North America!
It's not relevant to the UK, but here are the tone intervals reported by a Broadcom-based Actiontec Q1000H modem on an Annex A (Profile 8a) VDSL2 service provided in the USA by CenturyLink / Qwest.
Medley Phase (Final) Band Plan US: (6,31) (882,1193)DS: (41,857) (1218,1959)
Multiplying out again..
f1 = 41 x 4.3125 = 176 kHz
f2 = ~880 x 4.3125 = ~3.75 MHz (wider guard bands used by vendor)
f3 = ~1216 x 4.3125 = 5.20 MHz
So Annex A, which only supports one band plan is not compatible with Profile 8c used by Openreach.
It has been reported that BT Openreach is moving entirely to a G998 band plan. Since G998 and G997 cannot coexist in the same plant because of crosstalk and inter-carrier interference(?), the bandplan switch is presumably taking place at the same time as the DSLAMs are moved to Profile 17a.
At that point, will it matter whether Annex A or Annex B is used? Are the PSD Masks for G998 and G997 any different?