Int 15 Fn 8A  - Hunter 16 - Control Power Input (spm)                      [b]

   AH = 8Ah
   AL = new state of Power Input (00h disabled, nonzero enabled)
   SI = 1234h
   DI = 5678h

Return: AH = status
       00h success
       FFh failure
Desc:  Enable or disable Power Input. When Power Input is disabled the AC
     adapter will neither charge the batteries nor supply power to the
     Hunter 16. Disable Power Input if using Alkaline batteries.