Int 33 Fn 256C  - Logitech Mouse - Set Parameters - Set Baud Rate (serial  [M]

   AX = 256Ch
   BX = 0000h
   CX = rate (0=1200, 1=2400, 2=4800, 3=9600)

Return: AX = FFFFh if driver installed for serial mouse

See Also: AX=246Ch,AX=256Ch/BX=0001h,AX=256Ch/BX=0002h,AX=276Ch