The RCA inputs are usually analog so even if I used some device to play the content, there would be no display on the units other than "Input 1" or what your model shows.
-> Follow up your post with EXACT model numbers of this "head unit" so folk can see what other options there may be.
I have a wd wireless hdd and what I want to do is connect it to my tv or my in car head unit wireless. My head unit has an rca connection. Is there any type of device I can connect to the rca input that will recieve the data from my wireless hdd and the display it on to my head unit?