Hi Yetmo,
I am assuming you are using the iDJ which mixes two ipods and other equipment into a pair of stereo outputs for connection to your sound system (PA)…..Firstly you are confusing “inputs” with “outputs”…………inputs on the iDJ are for connecting the outputs of any outboard equipment such as CD players or Record Decks so that their signal is routed through the mixer section of the iDJ. Outputs on the iDJ are where you connect to the inputs of your PA system (either the amplifier or directly to powered speakers).
I am not familiar with this piece of kit so had to look up the Quickstart Guide http://www.numark.com/images/product_downloads/idj_quickstartguide.pdf. The outputs are on the back of the iDG (labelled 6 in the quickstart guide) and comprise of a stereo pair of RCA outputs (otherwise known as Phono sockets) which is where you would connect the cable to route the mixed signal out to your PA system. You will need either a twin (stereo cable) or two mono cables with male RCA (Phono) plugs on one end (to connect to your iDJ) and plugs on the other end to match the inputs of your PA amplifier or powered speakers which are likely to be either RCA, 1/4″ Jack or XLR.
Hope this helps.