With the M-Audio MIDISport 4x4 MIDI interface you can send and receive MIDI data from your DAW and hardware. You connect 4 audio devices with a MIDI connection, such as a synthesizer or drum computer with the interface. This way you use the sequencer from your DAW to write melodies and rhythms for your hardware. In addition to sending MIDI data, the interface also receives MIDI data. This way your DAW registers all physical changes you make to your hardware. For example, if you turn the filter cutoff of your synthesizer during recording, it will be registered in your DAW. Your hardware must be able to send MIDI signals.