Three part tutorial.
By Andrew Pask at Cycling 74
https://cycling74.com/2012/07/09/working-with-hardware-dmx-part-1/
https://cycling74.com/2012/09/11/working-with-hardware-dmx-part-2/
https://cycling74.com/2012/11/05/working-with-hardware-dmx-part-3/
