ENTTEC DMX USB Pro
From the Manufacturer:
Products don’t become an industry standard for no reason. The DMX USB Pro has proven for a number of years that it’s both a reliable and robust product usable for a number of applications. It has been adopted by multiple professionals across the world. The DMX USB Pro allows for simple USB 2.0 support through a robust USB-B connection, sending or receiving a physical DMX512 signal using PCs, Macs and Linux devices running a broad array of third-party software.