- Compact 1/3 rack enclosure- 4 inputs and 4 outputs in total- 3 MIDI inputs and 1 MIDI output on the front- 1 MIDI input and 3 MIDI outputs on the rear- Activity LED per port- Perfect MIDI timing- Power supply via USB bus- True plug & play installation- compatible with Windows XP/Vista/7, Mac OS X and Linux optional multidevice and multi-client driver for Windows XP/Vista/7/8 available via download