Question No auxiliary input on receiver (pioneer vsx-515-k)

[rainmakre]

Hi all,

I'm hoping someone can provide some guidance here. My father-in-law has a dated outdoor audio set-up (receiver (model: pioneer vsx-515-k), cassette deck, cd changer) but it seems to lack any auxiliary input. I'd love to free him from only listening to the radio and be able to use his phone to play whatever music free of ads.

Does anyone have any insights into how I can best accomplish this?

Thanks for all your help!
BC

set-up
back of receiver