> For the complete documentation index, see [llms.txt](https://docs.lightact.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.lightact.com/dmx/dmx-in/control-by-dmx.md).

# Master DMX Control

<div align="left"><figure><img src="/files/MOWYKZMDRJHT9ctSYWql" alt=""><figcaption></figcaption></figure></div>

To control software-level properties with DMX, you can use **Control by DMX** window.

To do this, open the **Control by DMX** window which you can find under *Tools* in the *Top Bar,* and enable it. Here you can trigger or control:

* **Master control**: Master Fade and Master Volume
* **Output fades**: Fades of Virtual outputs.
* **Global variables**.

With the **Universe** property, you can assign a Universe within which DMX values will control the above-mentioned properties.

In the *Start channels* section, the difference between two consecutive Start channels determines which Channels are reserved for each property.

By selecting the same **Universe** in the *DMX In* window, you should be able to see all the Channels that you have chosen, appear as green. If you **hover** over these Channels, you will see a tooltip with the property that is being controlled on that Universe and Channel.

<div align="left"><figure><img src="/files/pN61KNqroruz5bGmwTNS" alt=""><figcaption></figcaption></figure></div>

## Controlling Global Variables with DMX

<div align="left"><figure><img src="/files/KTuJWvtwjZAMxiYg9UxS" alt=""><figcaption></figcaption></figure></div>

To control global variables with DMX you have to set them up the same way as Layer variables. More information how to do that is available in [Controlling Layers with DMX](/dmx/dmx-in/adjust-layer-variables-with-dmx.md).