Beamz MHL1240 User Manual 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.
This unit has 5 control buttons, navigate the menu structure by pressing the buttons on the side of the display.
Exits from the current menu or function
Navigates upwards through the menu list or increases the numeric
value when in a function
Navigates downwards through the menu list or decreases the
numeric value when in a function
Enables the currently displayed menu or sets the currently selected
value into the selected function
Enables to invert display immediately, without searching in menu.
The display and control panel can be powered via USB-port (5V) . This gives access to the most important functions in the control panel, including DMX
addressing, when the unit is not connected to AC power.