Int 33/AX=256Ch/BX=0002h

AX = 256Ch
BX = 0002h
CX = rate (0=10, 1=20, 2=35, 3=50, 4=70, 5=100, 6=150)

Return:
AX = FFFFh if driver installed for serial mouse

See Also: AX=246Ch - AX=256Ch/BX=0001h - AX=256Ch/BX=0003h - Category: Mouse/Pointing Device - Int 33h - L