Ableton Link
Ableton Link plays openDJ in time with other apps and devices on your network, such as Ableton Live, a drum machine app or another DJ.
Open the MASTER button in the top bar and turn on Ableton Link.
Link follows the master deck: the deck that's playing, or the one started first while both play (see Sync and quantize).
For drum machines and other gear that follow MIDI clock instead, see MIDI clock.