I know this is an old post, but I thought I would mention that there are boards available from datasync to convert most wallboxes to MP3. I also have been doing this - one off - for decades for family gifts but recently started to sell on Ebay as well (search wallbox -MP3 ) The difference with me is that I have the wallboxes as well, and guarantee the whole thing works as the wallboxes themselves often have little issues. I will also sell directly if you want to save Ebay fees.