Code:
function StringtoHex(Data: string): string;
var 
  i, i2: Integer;
  s: string;
begin
  i2 := 1;
  for i := 1 to Length(Data) do
  begin
    Inc(i2);
    if i2 = 2 then
    begin
      s  := s + ' ';
      i2 := 1;
    end;
    s := s + IntToHex(Ord(Data[i]), 2);
  end;
  Result := s;
end;