USB to DMX with USB to RS232

Tried to Use a USB to rs232 Plug to use as an DMX Controller.

DMX is rs485 so i tried to put an Max485CPA between the rs232 and the DMX Light.

Controlling Masterdimmer, R,G,B works in Freestyler, but my light flickers permanent on/off.

So i think there must be any error. Missing any part....

Idee came from:

http://stevenbreuls.com/2013/05/diy-usb-dmx-dongle-interface-for-under-10/#comment-508