Beamz MHL1912 Mode D'emploi page 6

If you are using a standard DMX controller, you can connect the DMX output of the controller directly to the DMX input of the first unit in a DMX chain.
Always connect the output of one unit with the input of the next unit until all units are connected.
At the last unit, you must close the DMX line with a terminating resistor. Take an XLR connector and solder a 120 Ohm resistor
between signal (-) and signal (+) and connect it to the DMX output of the last unit in the line.