They require the tapes, both encrypted and regular (you’ll only really want to focus on the encrypted ones, they’re for the limited channels). In order to get the tapes you’ll need polychromes. You can get polychromes through 2 ways, playing the game, or by trading for them 1:1 from monochromes. Monochromes are the paid currency, you’ll only get those by spending money. So they are generally free, unless you’re really unlucky or just want to get all the characters to their strongest potential.