What do I need to use timecoded vinyl?

Hey there,
I am thinking about saving on integrating vinyl into my setup (timecoded of course). I don't plan to do this right now, as I just spend some bucks on a new laptop, but it might be something I want to get in the future
What I have:
Laptop (win 8.1)
CrossDJ
Reloop Beatmix (pretty standard controller, build in sc)
some speakers
What I plan on doing:
Use CrossDJ with four decks: Deck 1 & 2 controlled by my controller and deck 3 & 4 controlled by timecoded vinyl.
What I think I need:
The Cross Pack: http://www.mixvibes.com/products/cross-pack-0
Two vinyl turntables: (Any will do, right? These cheap guys for example: http://www.amazon.com/Numark-TTUSB-Turn ... +turntable)
What I do not understand:
Magnets, how do they work? No seriously, what is that "audio interface" good for? Do I need this to encode the timecodes? Do I need this at all, when I already got a sc in my controller?
I am thinking about saving on integrating vinyl into my setup (timecoded of course). I don't plan to do this right now, as I just spend some bucks on a new laptop, but it might be something I want to get in the future

What I have:
Laptop (win 8.1)
CrossDJ
Reloop Beatmix (pretty standard controller, build in sc)
some speakers
What I plan on doing:
Use CrossDJ with four decks: Deck 1 & 2 controlled by my controller and deck 3 & 4 controlled by timecoded vinyl.
What I think I need:
The Cross Pack: http://www.mixvibes.com/products/cross-pack-0
Two vinyl turntables: (Any will do, right? These cheap guys for example: http://www.amazon.com/Numark-TTUSB-Turn ... +turntable)
What I do not understand:
Magnets, how do they work? No seriously, what is that "audio interface" good for? Do I need this to encode the timecodes? Do I need this at all, when I already got a sc in my controller?