With an external instrument connected you can select it in the External MIDI Instrument’s drop-down list next to its display. Any MIDI ports available to Reason will appear—whether on a hardware MIDI interface, connected via USB, or virtual ports for software running on the same computer.
With the External MIDI Instrument you’ll be able to play your MIDI gear from your Master Keyboard, draw in notes in the Reason sequencer, or even control it from a Matrix Pattern Device or other sequencer available in Reason's rack.
Automating MIDI equipment from Reason’s sequencer or even from control voltages in the Reason rack is a breeze to set up. The External MIDI Instrument can send and automate MIDI program changes, record MIDI CC automation and control the pitch bend, mod wheel, keyboard velocity and aftertouch of external devices. One knob that can be assigned to any MIDI control is available right at the center of the device for controlling your hardware with your computer mouse.