PreFix Systems
Install guide

Installing PreFix

Written for someone who doesn't normally install software. If anything goes wrong, take a screenshot and send it to us.

What you need

  • A Windows 10/11 PC (64-bit), or a Mac with Apple Silicon (M1 or newer) on macOS 12 or later.
  • The download password.
  • Jeff Carmen's pIR HEG headset, if you have one. Without it, PreFix runs in Simulator mode so you can explore the app.

You don't need any developer tools. The installer includes everything PreFix needs.

Windows

  1. Go to prefixsystems.io/download, enter the password and click Download for Windows.
  2. Double-click the downloaded PreFix-Setup file. Windows will show "Windows protected your PC". Click More info, then Run anyway. This appears because PreFix isn't code-signed yet; it is not a virus warning. If you got the file anywhere other than prefixsystems.io or eegvault.com, don't run it.
  3. Click Next through the installer and Finish at the end.
  4. The headset driver (Phidget22) installs right after. If Windows asks "Do you want to allow this app to make changes?", click Yes. If it asks for a restart, you can restart later, but the headset won't work until you have.
  5. Open PreFix from the Start menu. You'll see a clinician window (controls and signal trace) and a patient window (the video). With two monitors, the patient window fills the second one.

Mac

  1. Go to prefixsystems.io/download, enter the password and click Download for Mac.
  2. Open the disk image and drag PreFix into Applications.
  3. Open PreFix. macOS will say it can't verify the app. Click Done, open System Settings → Privacy & Security, scroll to the bottom and click Open Anyway. The button only stays for about an hour; if it's gone, open PreFix again and come back.
  4. If macOS says the app is "damaged", open Terminal and run xattr -dr com.apple.quarantine /Applications/PreFix.app.
  5. For Jeff Carmen's pIR HEG headset, install the Phidget22 driver for macOS. PreFix starts the driver's server itself.

First run

With Jeff Carmen's pIR HEG headset (Windows)

  1. Open Phidget Control Panel from the Start menu.
  2. Once only: under General, check Start at login; under Network Server, start the server. PreFix talks to the headset through it.
  3. Switch back to PreFix. The trace should start moving within a few seconds.

If PreFix shows "HEG headband not detected", check the USB cable, that the Network Server is running, and that you've restarted once since installing. Then click Retry on the banner.

Without a headset

Click Use Simulator on the "not detected" banner to explore PreFix with a built-in practice signal. Switch to the real headset any time from the device menu in the clinician window.

Troubleshooting

A streaming service shows an error or a black box

Quit PreFix completely and reopen it, then try again. If one service keeps failing, use another for now and let us know.

The patient window is on the wrong monitor

Drag it to the monitor you want.

The headset isn't detected

Try a different USB port, then restart once. If it still doesn't appear, contact us.

Uninstalling

Windows: Settings → Apps → Installed apps → PreFix → Uninstall. The Phidget22 driver is listed separately. Mac: drag PreFix from Applications to the Trash.