To use the Denon DJ X1800 or X1850 Prime mixer with DVS control and Serato DJ, you will first need to purchase a Serato DJ licence and a DVS Expansion Pack licence (these two products have been bundled together as the Club Kit). 
You can purchase the Club Kit HERE.

For more information about the required licences to use a Club Kit ready mixer, check out the Club Kit licence guide here.

Once you have purchased the Club Kit (or individual licences separately) enable CD/Vinyl Control in the DVS Expansion Packs section of the SETUP screen under the Expansion Packs tab. Follow the steps below to get DVS control working with the Denon DJ X1800 or X1850 Prime mixer:

1. Install Drivers (Windows only)

The Denon DJ X1800 and X1850 Prime mixers require drivers on Windows, but are a class- compliant devices for macOS. For Windows, please make sure you have the latest drivers & firmware installed, while Mac users just need to ensure the latest firmware is installed.
On Windows, simply connect the mixer to your computer and open the latest version of Serato DJ. You should see an "Install Driver" dialogue box appear in the right hand side-panel. Click "Install Driver" and follow the installer prompts. If you don't have the hardware with you right now you can still download the driver from the manufacturers website. 
Visit the Denon DJ X1800 Prime page here
Visit the Denon DJ X1850 Prime page here

    

2. Connect & select Input source

If you have connected an analogue source (like turntables), make sure you have connected it to the input entitled 'Phono', if you have connected a digital source (like CDJs or turntables with a LINE out) make sure it is connected to the input entitled 'Line' accordingly.

Ensure the input selector at the top of the channel strip's used, is set to 'DVS'.Remember to change the USB selector on each channel strip to correspond to the USB port your computer is connected to.

3. Select Primary Decks

Also in the AUDIO tab of the SETUP screen, you will need to select your Primary Decks.

Choosing Channel 1 and 2 will allow you to have a traditional 1-2-3-4 channel configuration. Choosing Channel 2 and 3 will allow you to have a 3-1-2-4 configuration (from left to right across the mixer).

Select which deck configuration you are using with the mixer and change if necessary. If you notice you are getting signal from your control tone but on the wrong deck, you might need to double-check your Primary Decks in the SETUP screen or the physical inputs on the back of the mixer.

You are now set up to use your mixer with Serato DJ and DVS control using the REL or ABS control modes. See the Serato DJ software manual for more information on Control Modes.