MANY MODERN GUITAR EFFECTS include a USB port that lets the processor act as an audio interface when connected to a computer. Some effects even include a computer-based editor so you can tweak parameters and save/load presets to/from your computer. But for everything to work smoothly, observe these USB survival tips.
Adding a USB port card to your computer can solve a variety of USB-related issues.
 A class-compliant device can plug directly into a USB port—no driver required. Current Mac and Windows machines (update the OS to the latest version for best results) will recognize the device, but as custom drivers generally give better performance, use them if available.
 A USB 2.0 interface is much faster than a USB 1.1 interface, and it can handle more channels of audio at higher sample rates. Although USB 1.1 and USB 2.0 are interchangeable, a USB 1.1 device won’t run faster with a USB 2.0 port, and a USB 2.0 device will slow down when connected to a USB 1.1 port.
 When installing Windows driver software, read the instructions carefully. It’s common to install the driver software first, before connecting the accompanying device (but not always—read the documentation). After installing the drivers, plug in the USB device. Once the computer recognizes it, you can use it.
 Unplug all unneeded USB devices (everything except keyboard and mouse) prior to installing drivers.
 If during Windows installation you’re warned that the driver has not passed Windows logo testing, click on “Continue Anyway.”
 If the USB device has memory for storing patches, it will likely show up as an external computer drive. Before physically unplugging the USB effects device, eject it properly. Mac: Drag the USB drive icon to the trash, and wait several seconds before actually removing the USB connection. Windows: Click on the Safely Remove Hardware button in the taskbar, then click on the USB device you want to eject.
DigiTech’s GNX4 was one of the early guitar effects to include a USB port.
 Most music-related USB devices recommend connecting directly to a USB port in the computer itself, not through a USB hub (especially if it’s an unpowered hub).
 The USB ports built in to computers may not be suitable for high- performance audio. I’ve solved many USB problems by simply adding a USB PCI pr PCIe card, and using its ports only for audio. Avoid combo USB/FireWire cards, as some users report performance issues.
With Windows, if you plug a USB device into a port other than the one used during installation, you may be asked if you want to install the drivers. Select the Install Automatically option. Now both ports will recognize the device.
 If your computer doesn’t recognize a USB device after you’ve installed the drivers, unplug the USB cable, wait a few seconds, and then plug it back in again. Sometimes, the computer will “overlook” the USB device when booting up, but will recognize it when plugged in.