
The Enttec DMX USB Pro is a fairly low-cost (123 Euros) USB to DMX controller. I've had one for a couple of years and it's proven to be reliable.
In order to get it to talk to Max/MSP you will need the dmxusbpro external from nullmedium, it only costs 10 Euros and is available for Mac, PC and Linux as well as Max/MSP alternative PD.
The external comes with a help patch and instructions for installing the USB driver - if you need to.
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