A:
The wireless kit uses the LFE input ( also called Co-ax, Digital Co-ax, Sub-woofer cable input, Raw input, etc.) but its basically a RCA cable (Red-White) combined into a high quality audio cable specifically for sub-woofers. Look on the back of your sub-woofer, it typically will have a (1) a standard power cable input, plug that into the wall (2) four pairs or more, wire terminals (red - black for positive and negative) these are just so you can wire your speakers to the sub-woofer and than to the receiver (don't use them) (3) a RCA, red and white input (first option to plug the sub-woofer into your receiver (4) A LFE input (best option) to plug into your receiver.
Only use either the RCA pair or the LFE input to connect the sub-woofer to the receiver (in the case of this kit use the LFE input to plug the sub-woofer into the box and the other box into your receiver) LFE is best because it doesn't use any filters built into your sub-woofer and instead uses the ones in your receiver which are much better.