Question about uIEC daughterboard switches

[ral-clan]

Hi, I have bought a uIEC with daughterboard. I haven't used it yet, but there are several switches on the daughterboard I can't find clear documentation on:

SWAP
FORWARD
BACK

I think these are supposed to either jump forward or backward to the next disk image on the device - OR consult a .txt file listing groups of disk images (i.e. disks that are part of a single game) and swap through those.

I don't understand what the SWAP button does. If you can already swap disk images with the FORWARD and BACK button, why do you also need a SWAP button?

I am thinking about mounting the uIEC without the daughterboard in an external case. In this case, there doesn't seem to be provision for the SWAP button on the 13 pin connector. Is the lack of a SWAP button on embedded or external case modifications going to be a hindrance?

Thanks.