I think the USB port on the FR-18 is designed to receive a memory stick to transfer keyboard setups and other customization tweaks. Pretty sure you want to use the FR-19's midi out with an appropriate cable into your computer's sound card or other hosted midi in to trigger recording software. I think you'll end up running the software synth in that computer program, using the FR-18 as the input device (controller). I tried it once with Reason, and it worked as a midi controller with that type of setup.