def h2i(self, pkt, seconds):
        """Convert the number of seconds since 1-Jan-70 UTC to the packed
           representation."""

        if seconds is None:
            seconds = 0

        tmp_short = (seconds >> 32) & 0xFFFF
        tmp_int = seconds & 0xFFFFFFFF

        return struct.pack("!HI", tmp_short, tmp_int)