Toshiba A100 - AT Commands

User’s Manual C-3
V.90/V.92
AT Commands
-V90=* V.90 Dial Line Rate
-V90 sets the maximum V.90 downstream that the modem
attempts to connect.
-V90=0 V.90 disabled
-V90=1 V.90 enabled: automatic speed selection - maximum modem
speed (default)