Int 15 Fn 6E  - Hunter 16 - Enable/trap Event                              [b]

   AH = 6Eh
   AL = Software Interrupt
         00h  do not trap event
         else trap as software interrupt number AL
   BH = event number (see AH=6Dh)
   BL = enable mask
       00h disable event
       01h enable event

Return: AH = 00h if successful

See Also: AH=6Dh,AH=6Fh