Int 2F Fn FA00  - Multiplex - ??? - Installation Check???                  [-]

   AX = FA00h
   BX = ??? (0408h)
   CX = ??? (001Fh)
   DX = ??? (0102h)
   SI = ??? (5ACCh)
   DI = ??? (0632h)

Return: ???

Note:  called by WinEmacs at startup