Want to pile-on two DMX512 sources? You can't just tie the outputs together like you can with 0 to 10 volt analog control signals. Combining two DMX512 sources requires a computer, like the one in the model 221E DMX Combine Unit.
The combiner introduces the minimum delay possible with DMX512, less than 0.02 seconds. Combine units are available in up to six input configurations as standard products. For more than 6 inputs, multiple units can be linked together. These combiners feature terminated opto-isolated inputs which are also protected from AC line crosses and transients. Each input has an LED signal indicator. These combiners can also be used to convert to, or from, Colortran's CMX protocol (as used in D-192 series dimmers)