This opto-coupler device USB2.0 ports, isolates your data acquistion device from power surges or transients. Plug your USB device into the isolator and then plug the isolator into a HUB or PC. The PC and your USB device now have no electrical connection but can still talk to each other. The module also transfers power from the PC to your USB device with no electrical connection. Your USB device is now protected and can be attached to other ground potentials without any ground loops that could destroy your computer,USB device and other attached electronic devices.