connect to cdj 2000 isue

hi can someone please help me? i have record box perform licence !! in one of studio that i use to practice my recordbox i use usb cable and its plug and play 

but when i enter the club it have cddj2000 i conect my record box using usb cable  its conect to cdj,  i can play the track was runing but it didn't come out trough the djmixer (its djm900) why it come like that? 

i dont know maybe the audio seting or etc please answer my question :) thanks...