Question: what cdjs are compatible with traktor?
Answer: At this time Traktor only supports advanced HID mode for the CDJ 2000 Nexus, CDJ 2000, and CDJ 900. For those with CDJ 850s don't hold your breathe, people have been asking a long time and it hasn't happened, so the only option is using the CDJ 850 Traktor mapping or timecode CDs.