To use the Allen & Heath XONE:DB2, XONE:DB4 and XONE:43C mixers 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 XONE:DB2, XONE:DB4 and XONE:43C mixers:

1. Install Drivers

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. Go to Allen-Heath.com here
    

2. Select Input source

Once your turntables or CDJs are connected to the mixer, check that you are using the correct Input setting on the back of the mixer. If you have connected an analogue source (like turntables), make sure you have the input set to PH (Phono), if you have connected a digital source (like CDJs) make sure it is set to LN (Line) accordingly.

NOTE: If you are using a XONE:43C, you will have LN/PH switches for each channel. If you are using the XONE:DB2 or XONE:DB4 and want to connect an analogue source to channels 1 or 4, you will notice there is no switch on the rear of the mixer and will need to enable the hardware preamp (Soft RIAA) for those channels. See the XONE:DB2 or XONE:DB4 hardware user guide for more information.

Download: XONE:DB2 Hardware User Guide (see Soft RIAA on page 23)
Download: XONE:DB4 Hardware User Guide (see Soft RIAA on page 29)

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.