According to this Jensen document:
http://www.jensenrvdirect.com/downlo...eally_mean.pdf
You need a SCC1BL (which is a Sirius/XM manufactured part). Doing a google search it does look like that guy is hard to find (and may be discontinued so they may be right) but I did find it for sale here:
JENSEN SIRIUS Gen. 3.0 Radio Receiver - MARINE AUDIO / VIDEO - CRUISING
I upgraded the radio mostly because I wanted bluetooth and navigation functionality. The 215 also states that is "Sirius Ready" and has a socket on the back labelled as "SXM". (With bluetooth it is possible to just use the SXM streaming app on a phone or tablet without having to pay for an extra SXM receiver--although you do have to have good cell coverage where you are going.)
I wasn't able to find the radio on any Jensen sites available for sale..only at that one RV parts supplier (the link is in the very first post in this thread).