program terminal;
uses crt;

Const
  { (1=$03F8 2=$02F8 3=$03E8 4=$02E8 }
  Com = $2f8; {Alapértelmezés: com 2}

Procedure Write(w : char);
begin

 asm
  mov al, w;
  int $29
 end;
end;

var
 c : char;
 done : boolean;

begin
  done := false;
  repeat
   if keypressed then
       begin
          c := readkey;
          if c = #27 then done := true;
          port[com] := ord(c);
       end;
   if  97 = port[com+5] then write(char(port[com]));
  until done = true;
end.