What Is DMX

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This tutorial is an introduction to DMX.


Date: 08/2014


DMX is the standard digital protocol to control lighting fixtures on a stage. It was standardized in 1990 by the United State Institute for Theater Technology (USITT) and was called DMX512/1990. The actual DMX standard is called DMX512/A and contains several additions, but it is also compatible with the old standard DMX512/1990.


What do we need to install a stable DMX line?

DMX Interface

Includes hardware devices, like the MADRIX NEO, MADRIX PLEXUS, or MADRIX LUNA.
A DMX interface sends the control signal for a maximum of 512 DMX channels per DMX universe.  The control information will be transmitted by using a data word of 1 Byte [8 Bit]. That is the reason why you can control each DMX channel with 256 steps [0-255].

DMX  Interpreter/Controller

Can usually be foun inside a fixture. It receives the DMX signal, interprets it, and changes the values of each attribute of the fixture to the desired value which is set by the DMX signal.

DMX Connectors

As described in the DMX512 specifications, a 5-pin XLR connector has to be used. The first pin is used for ground, the second pin for the inverted DMX signal ['Cold'], and the third for the DMX signal. Pin four and pin five are occupied for other tasks, which are specified in the DMX512/A norm. That means in most cases that a 3-pin connector will suffice, but as mentioned above that is not the norm of DMX512.
Connectors are available in 2 designs, male and female. The male connector is connected to the transmitter [DMX interface] and the female connector is connected to the receiver.

DMX Cables

It is recommended  to use only cables with an impedance of 110 ohm. Otherwise, it is possible to get unwanted side effects.
A DMX connector is found at each cable ending: The male connector on the one side and the female connector on the other side.

DMX Fixture

Includes lighting devices, such as Dimmers, RGB fixtures, and Moving Heads.
DMX fixtures receive and interpret the signals from the DMX controller according to the allocated function of the channel. Furthermore, the DMX signal will often be forwarded. In many cases, a DMX fixture features a DMX-IN as well as a DMX-OUT connector. This allows to daisy-chain a certain number of DMX fixtures.
Note: You should feed the signal anew after a maximum of 32 fixtures, because the DMX signal strength will be too weak otherwise.

DMX Splitter

A DMX splitter mainly splits and duplicates an incoming DMX signal into several DMX output signals. Each output signal is basically the same. It is like a Y-split cable for the audio engineer. But at the same time, the DMX splitter amplifies the signal to ensure the signal strength.

DMX Booster

A DMX-Booster amplifies the incomming DMX-Signal. That is necessary if the signal is to low for the nex DMX-Fixture.

DMX Terminator

A DMX terminator of 120 Ohm impedance should be used at each last fixture or end of a DMX line! If not, unwanted transmission interference is common. The terminator is connected to pin two and pin three of a male connector.

DMX Universe

A DMX universe consists of 512 DMX channels. If you need control more than 512 DMX channels in your installation, it is necessary to use an additional universe or even more.


Congratulations! This tutorial should have provided important information on how to build a stable DMX line.

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