This apples to the iTrack Dock

The USB MIDI port on the iTrack Dock is for connecting class compliant USB MIDI controllers. Class compliant devices do not need a driver to be installed to work. 

A list of USB MIDI devices that we have tested and found to work with the iTrack dock as well as some known incompatibilites can be found below.

NOTE: The USB port on the iTrack Dock is designed for connecting MIDI controllers directly. We do not support the connection of USB hubs to the port. We also do not support the connection of other sorts of USB device (i.e. a USB interface) - the port is for MIDI controllers only.

USB MIDI controllers tested with iTrack Dock’s MIDI port and found to work:
Novation Launchkey range (mini, 25, 49, 61)

Novation Launchpad S

Novation Launchpad Mini

Novation Launch Control

Novation Impulse range (25, 49, 61)

Novation Nocturn range (25, 49, 61)

Novation SL MkII range (25, 49, 61) - Please note: the Novation SL MKII range needs external power to work with the iTrack Dock

Akai Max 49 - Please note: the Akai Max 49 needs external power to work with the iTrack Dock

Alesis QX61

Casio PX-5S

Casio PX 350m

Casio CTK 4200

Korg PA 600

M-Audio Axiom Air Mini

M-Audio Oxygen range (25, 61) 

Sanoxy USB MIDI Cable Convertor

USB MIDI controllers tested with iTrack Dock’s MIDI port and found to be incompatible:

Akai MPK Mini MK1 & MK2

Arturia Keylab 61

Korg microkey 37

Korg MS-20 Legacy Edition Controller (MS20iC)

Not officially tested but we have heard of issues with the following units:

Akai MPK225

Alesis Q25

Alesis Q49

Arturia MiniLab USB

Behringer X-Touch Universal Control Surface

iConnectivity Mio

Korg NanoKey 2

Korg NanoPad

Korg nanoKONTROL 2

M-Audio Code 61

Native Instruments Kontrol S-Series