Virgil

What can I do with the optical cable included? I recently got a N707 and I'd like to record some music digitally to the MD from a portable cd player(for example). I don't know if I should remove the plastic 'bulbs' on the ends of the cable, but with them the cable doesn't fit in the MD. I think that if I try to remove the bulbs it may break the plastic ends. Or do I need to purchase something extra? I don't know, input please? :? Thanks.