Int 66 Fn 12  - Pendos - Tdmouse.exe - Initialize                          [n]

   AH = 12h

Return: CF clear
   AX = 0000h

Note:  this function calls the old mouse handler with functions 0000h, 0002h,
     0007h, 0008h, 000Fh, 0004h, and 000Ch (in that order)

See Also: AH=13h