SFX can input and output MIDI commands.  In SFX Deluxe, you can also input and output MIDI Show Control commands.

Many devices understand MIDI, from mixing consoles and effects processors to light consoles and custom devices.  You can create MIDI cues in SFX that transmit commands to these type of devices.  A common use is sending a MIDI command that triggers GO on a lighting console or sending a Scene Change command to a mixing console.  You have total freedom to choose the MIDI commands to transmit.

SFX can also be triggered by MIDI.  You can directly assign cues to certain MIDI commands, or you can assign a general GO to a MIDI command.  With SFX Deluxe, you can also create a script of commands that will run when a designated MIDI command is received.