I don't get buses often, but from my limited experience, what is expected of me (the customer) is to drop €2.30 into the slot thing and the driver prints me my ticket.
So I got on a bus just five minutes ago with my earphones plugged in, got €2.30 out of my wallet and dropped it into the slot. The driver looked at me questioningly. I took my earphones out to hear what he wanted to say, but all he did was continue staring quizzically at me. I tentatively uttered "eh... €2.30?" he shrugged and printed me my ticket.
What did he want from me?