One really cool thing about using the To Host port is that it turns the keyboard itself into a MIDI interface for your computer, even if you don’t currently have one! All you need is the serial port that most PCs and Macs (pre-USB) come standard with! Any MIDI channels that your keyboard isn’t using for itself (or even that it is, if you don’t mind “sharing” can be passed on out the keyboard’s MIDI Out port to any other MIDI device(s), and also info received from MIDI In can be passed back to the computer through the To Host port.