Question about Serato SL3

I have a question about the thru function on sl3 - with sl3 there is a combined output for timecode and regular playback unlike sl1 where there are separate outputs for each. With sl3 in the software you choose 'thru' and the interface switches playback from timecode to regular playback on the same out put, but i was wondering when your laptop is not connected and you just want to play a record whether when the software is not active there is an automatic thru chosen by the interface? If this is not the case and I just wanted to put on a vinyl record I would have to unplug my turntable out put from the box and straight into the mixer which would be a pain in the ass. Thanks for any help!