Configuring a PC USB port as a virtual serial port

For example, the Trimble WinFlash utility can be run on a computer that has no physical serial port by connecting the USB cable between the computer and the receiver.

Windows 8 operating system

  1. There is no Windows8 USB Installer file; the Windows7 USB Installer file works for Windows 8.

    This file contains a Support Note and installation program.

  2. Run the installation program. It will load the virtual serial port for the USB interface on your computer .

    With Windows 8, the USB ports are often version 3.0. With Windows 8 there is a conflict with the implementation of USB version 3.0. To workaround this, go to the computer's BIOS settings when you start up the computer and then turn off the support for USB 3.0.

Windows 7 Professional operating system

  1. This file contains a Support Note and installation program.

  2. Run the installation program. It will load the virtual serial port for the USB interface on your computer.

If this process does not work for your computer, or if you have a different Windows operating system on your computer, then follow the procedure below.

Windows 7 operating system

  1. Go to the Trimble Support website (www.trimble.com/support) and search for the receiver you have. In the Support Notes section, download the file called SPS GNSS Interface to a Virtual COM port on a Computer to your computeror USB drive.

  2. Open the file and place the trmbUsb.inf file in a temporary folder on your computer or USB drive.

  3. On the computer, select Control Panel / Device Manager.

  4. Click on the name of the computer and then from the Action menu, select Add Legacy Driver.

  5. A wizard prompts you to locate the TrimbleUsb.inf file. Locate the file and then follow the prompts in the wizard to continue.

If you are running an application such as WinFlash software or Trimble Installation Manager on the computer and you physically disconnect the USB cable from the computer and then reconnect it, it does not always re-establish the connection. This is because opening the serial port from the application locks the device handle and when the USB device is disconnected, the application does not close the serial port and the device handle is still locked. On reconnecting, the USB cable is unable to get the device handle since it is locked. You must close the application before the reconnect to the port will work. This limitation is due to the behavior of the Microsoft USB serial driver.