Here is a short video of the Native Instruments Traktor Kontrol S4 using its internal soundcard for total timecode control with two Denon DN-S3700 Multimedia Controllers. The setup process is very simple and you don't need any additional hardware to make it work. All you need is RCA cables and Traktor Scratch Pro 2 software and a set of timecode CD's or timecode Vinyl. You can then control two of the four Traktor decks using external units. This way the DJ has all four decks of control at any given time without having to switch between one deck or the other. At the present time, I don't think there are any other four-deck controllers out there on the market that can do this without the use of another external soundcard and a lot more hassle. This makes it very easy for anyone to do.
Free Scratch Upgrade for Traktor Kontrol S4 Users
Just last week I put out a video showing the Traktor Kontrol S4 DJ controller working with external decks using timecode in order to operate all four decks simultaneously with a lot more control. This video was done on Traktor Pro 2 at the time, but now Native Instruments is giving away a FREE "Scratch Upgrade Kit" which will allow users to mix and scratch with timecode via the directly connected turntables or CD decks. Check inside for more information.