The UFX1204 and UFX1604 are the only mixers in the XENYX range that are capable of true multi track recording over USB/Firewire. If you are multi track recording into DAW (digital audio workstation) then you need to follow these simple steps. Firstly if you are using a PC you will need to download the driver for the mixer to function properly with your computer. For each product there are both USB and Firewire drivers for download on the product's page depending on which connection you would rather use. Please note for Mac OS no drivers will be required http://www.behringer.com/EN/Products/UFX1204.aspx http://www.behringer.com/EN/Products/UFX1604.aspx Once you have the driver installed you can plug your mixer into your computer via USB/ Firewire. Depending on which connection you are using you need to set the switch on the back of the unit correctly. You will then be able to select the mixer as the input and output device in sound settings of your computer/ mac. In your DAW you will then need to go into your Audio Preferences to once again set the mixer as your input/ output you will also be able to configure your inputs so that all inputs can record to individual tracks. For example in Ableton Live you would go into Preferences set the UFX as your input device and then click 'Input Config' on this page you can click on the inputs you would like to make available, available inputs will be shown in yellow. If for example you are recording a live show then there is no need to bring your laptop along in order to record multiple tracks. The UFX mixers have a stand alone feature (switch in the middle position) where by you can record multiple tracks straight onto a USB stick for extra convenience.