It's just not clear in the description page.
Pre-cue your tracks
Pre-listen the next track in your headphone and prepare your transition. All you need to do is to plug your audio split cable and turn on Split mono mode. To pre-listen the next track, go to the EQs tab and press the button to pre-cue your tracks. Works also with external mixer: control EQs and crossfader with hardware mixers. Watch video here.
Multichannel audio for devices running Android M: For devices running Android M, the app provides dual-stereo output. Users now can pre-cue in stereo, while having a stereo master output at the same time.
MIDI ControlConnect your Android device to the U-Mix Control-Pro, the Pioneer DDJ-WeGO2 and the Pioneer DDJ-SB: all Cross DJ controls are mapped. Browse, scratch, sync tracks, add effects… everything works at a very low latency. Watch the video:
http://youtu.be/5ocke5GDg78MIDI Control for devices running Android M: On those devices, MIDI control in Cross DJ is now Plug & Play.
If I connect my Hercules RMX2 on my Samsung Galaxy Tab A6 (Nougat, Android 7) with Cross DJ Pro Android
1) do I have the master (outputs 1-2) and pre-cueing (outputs 3-4) audio?
2) Can I use MIDI? Even if I must do the mapping myself?
Bonus: RMX2 is plugged on sector, can it charge the Tab from the USB connection?