A new version of
BT SIN 498 was published recently. This is the document that specifies the requirements of VDSL2 modems for FTTC.
They added a requirement that a modem must support vectoring and downstream retransmission (G.INP) both in use at the same time.
A strange thing is they updated the note after the list of VDSL2 requirements, to say that downstream G.INP is now in use, but it still says that upstream G.INP isn't currently enabled.
They also increased the maximum time allowed for a modem to train-up (establish "sync") from 60 to 90 seconds. Apparently that tends to take longer with vectoring in use.
