procedure TForm1.Button1Click(Sender: TObject);
var
   FCS  : integer;
   w_i  : integer;
   w_ii : integer;
   w_b  : byte;
begin
   // Line pointer in Listbox
   for w_i := 0 to ListBox1.Items.Count - 1 do
      // Check for correct string length
      if length(ListBox1.Items.Strings[w_i]) = 56 then
      begin
         FCS := 0;
         // Byte counter in frame
         for w_ii := 1 to 14 do
         begin
            // Move string hex byte into binairy byte
            HexToBin(StrLower(pchar(copy(ListBox1.Items.Strings[w_i], ((w_ii - 1) * 4) + 1, 2))), @w_b, 2);
            // XOR with previous Result
            FCS := FCS XOR w_b
         end;
         // Add FCS result to listbox
         ListBox1.Items.Strings[w_i] := ListBox1.Items.Strings[w_i] + ' FCS=' + IntToHex(FCS, 2)
      end;
end;