Installing USB Driver

Download and install the latest USB Driver from http://redigate.elecsyscorp.com/software
Make sure to install the correct version of driver for your operating system:
For Windows 64-bit, use CP210xVCPInstaller_x64.exe
For Windows 32-bit, use CP210xVCPInstaller_x86.exe

To verify your version of Windows, right-click on the System icon in the Start menu or Windows Explorer, or select System in the Control Panel:
Power on the RediGate, and connect a USB cable from the configuration computer to the console port on the front of the RediGate (USB type A male to Micro-USB type B male). The Windows operating system should recognize the port as a USB serial port.
Open the Windows "Devices and Printers" window to confirm that the device appears as a "Silicon labs CP210x USB to UART Bridge," with a "COMx" port number designation, as shown in the following screen capture:
If the port is not recognized as a USB serial port, see if the device appears in the Windows Device Manager as an unknown device – this may indicate that the driver was not installed properly.

Also, try a different USB port on the computer, or try a different cable.
If you have a second RediGate, try plugging into its USB port.
It should not normally be required to reboot Windows, but you might try that as well.