At first glance, you wouldn't think a Square reader could substitute as a reel-to-reel player, but it does and Evan Long has a video to prove it. Before you start calling shenanigans, remember that the Square reader is nothing but a magnetic head designed to read the magnetic strip of a credit card. As Long shows, it's not too far of a stretch to get it to read a magnetic tape.
Long details the process in a blog post and shows how he cracked open the Square reader, bent the holder to fit the reel tape and connected it to the iPod Touch. This particular reader is likely an older version which sends its data in an unencrypted format. Long then reads this data and plays it back with a custom playback app (available on github). You can see Long's hack in action in the YouTube video below and read more about it on his website.