Дима, да ты ленив...
at-v90=??
AT-V90=0 Disables V.90.
-V90=1 Selects auto rate (default).
-V90=2 Selects 28000 bits/s.
-V90=3 Selects 29333 bits/s.
-V90=4 Selects 30666 bits/s.
-V90=5 Selects 32000 bits/s.
-V90=6 Selects 33333 bits/s.
-V90=7 Selects 34666 bits/s.
-V90=8 Selects 36000 bits/s.
-V90=9 Selects 37333 bits/s.
-V90=10 Selects 38666 bits/s.
-V90=11 Selects 40000 bits/s.
-V90=12 Selects 41333 bits/s.
-V90=13 Selects 42666 bits/s.
-V90=14 Selects 44000 bits/s.
-V90=15 Selects 45333 bits/s.
-V90=16 Selects 46666 bits/s.
-V90=17 Selects 48000 bits/s.
-V90=18 Selects 49333 bits/s.
-V90=19 Selects 50666 bits/s.
-V90=20 Selects 52000 bits/s.
-V90=21 Selects 53333 bits/s.