Alpine CDA-7892 CD Player "auxiliary input device comes car" Questions

...auxiliary input into a pioneer DEH-1400. The design of this unit is highly modular and thanks to the engineers who designed it there is an easy, straightforward way to add an aux input to the unit. ...

...auxiliary input adapter (KCA-121B) or iPod adapter (KCA-420i). yeah, I did that too, thinking the rca jacks in the back of the deck would work. However, I did purchase the "aio-net" adapter from best ...