The switch is for allowing the connected card to be accessed. I have one with no attached cards. Mine is a 1 meg card for non backlit. If having the card in and switch either direction doesn't change your available ram, then it's for non backlit model. If that is the case I would love to take a attach card off your hands lol. My portable is great with 3 Meg's but one more meg would make it better than my plus (cause of the extra MHz).