V.34
Leased Line mode doesn't fall-back or fall-forward
between different modulation modes (i.e. V.34 to
V.32bis) and vice versa ?
ITU-T standard V.34
supports speeds from 2400 to 28.8K bps; a range
wide enough for users. Different modulation fall-back
and fall-forward are not in definition and do not
become necessary.