packet.append(0x00)  # Physical

            universe_nr = 0

            packet.append(universe_nr & 0xFF)  # Universe LowByte

            packet.append(universe_nr >> 8 & 0xFF)  # Universe HighByte

            packet.extend(struct.pack('>h', len(buf)))  # Pack the number of channels Big endian

            packet.extend(buf)

            self._socket.sendto(packet, ('127.0.0.1', 6454))

class Udmx(BackgroundLoopOutput):

    def __init__(self, uri: URIRef, bus: int, address: int, lastDmxChannel: int, rate=22):

        self.bus = bus

        self.address = address

        self.lastDmxChannel = lastDmxChannel

        self.dev = None

        super().__init__(uri, rate=rate)

        self.reconnect()

    def shortId(self) -> str:

        return super().shortId() + f'_bus={self.bus}'

                    return self.crash()

                if e.errno == 19:  # no such dev; usb hw restarted

                    self.reconnect()

                    return

                raise

'''

# the code used in 2018 and before

class UdmxOld(BackgroundLoopOutput):

    def __init__(self, uri, bus):

        from light9.io.udmx import Udmx

        self._dev = Udmx(bus)

        super().__init__(uri)

    def _write(self, buf: bytes):

        try:

            if not buf:

                return

            self.dev.SendDMX(buf)

        except usb.core.USBError as e:

            # not in main thread

            if e.errno != 75:

                msg = 'usb: sending %s bytes to %r; error %r' % (

                    len(buf), self.uri, e)

                log.warn(msg)

            raise

# out of date

class EnttecDmx(BackgroundLoopOutput):

    stats = scales.collection('/output/enttecDmx', scales.PmfStat('write', recalcPeriod=1),

                              scales.PmfStat('update', recalcPeriod=1))

    def __init__(self, uri, devicePath='/dev/dmx0', numChannels=80):

        sys.path.append("dmx_usb_module")

        from dmx import Dmx

        self.dev = Dmx(devicePath)

        super().__init__(uri)