code: public static long extractTimestamp48Ascii(String id48ascii) throws NumberFormatException {
          return extractTimestamp48(Long.parseLong(id48ascii, Character.MAX_RADIX));
      }
docs: Extracts the (UNIX) timestamp from a 48-bit ASCII id (radix
  {@link Character#MAX_RADIX}).
  
  @param id48ascii
  @return the UNIX timestamp (milliseconds)
  @throws NumberFormatException