Int 16 Fn 7E  - PCanywhere Iii - Communications I/o Through Port           [R]

   AH = 7Eh
   AL = subfunction
       01h port input status
       Return AX = 0 if no characer ready,
              AX = 1 if character ready
       02h port input character
       Return AL = received character
       03h port output character in CX
       11h hang up phone