USB-RS485B - Low cost DMX512 Transmitter

The USB-RS485 is a complete, self powered, USB to RS485 interface working at any baud rate up to 250k baud. It features automatic bus turn-around - any time your not transmitting the module is listening.
Uses the ST485 quarter power tranceiver, so you can have up to 128 devices on the bus.

USB interface uses the Silicon Concepts CP2102 chip which has drivers available for Windows, Macintosh, Linux and Android. 

The USB-RS485 can also be used to generate a DMX stream, see examples on product page for more info

USB-RS485B Documentation 

Examples:
DMX generator - Program allows the USB-RS485 to be used to generate a DMX512 stream, fully controllable from Windows GUI. We also have a user manual