StringToHex

function BytesToHex(const ASource: TBytes): string;
var
  target: TBytes;
begin
  SetLength(target, Length(ASource)*2);
  BinToHex(ASource, 0, target, 0, Length(ASource));
  result := TEncoding.ANSI.GetString(target);
end;

function StringToHex(const ASource: string; AEncoding: TEncoding): string;
begin
  result := BytesToHex(AEncoding.GetBytes(ASource));
end;

function SeparateString(const ASource, ASeparator: string; AChunkLength: Integer): string;
var
  I: Integer;
begin
  result := ASource;
  for I := Pred(result.Length) div AChunkLength downto 1 do begin
    Insert(ASeparator, result, I*AChunkLength + 1);
  end;
end;

function UniLE2HexStr(const s_in: string): String;
begin
  result := SeparateString(StringToHex(s_in, TEncoding.Unicode), ',', 2);
end;