FLEX-1500 USB Performance Degradation Due to Other USB Connected Devices

The FLEX-1500 connects to a USB (universal serial bus) controller in your PC.  This USB controller can have multiple ports to connect multiple devices to it.  The FLEX-1500 works optimally, especially on CW, when it is the only device on the USB controller.  The reason for this is that if a lower speed device like a keyboard or mouse is connected to the same controller as the FLEX-1500, all devices on the controller will operate at the speed of the device with the lowest speed.  This can severely degrade the performance of the FLEX-1500 resulting is erratic keying using the internal keyer and long latency or a lag between key closure and hearing the sidetone.

The following procedures will describe how to determine if the FLEX-1500 is sharing a controller with other devices.  If it is, then moving the FLEX-1500 or the shared devices to a different USB port will allow the FLEX-1500 to operate on its own port at the full rated speed.


USBDeview from NirSoft is a small "freeware" utility that lists all USB devices that currently connected to your computer, as well as all USB devices that you previously used. For each USBdevice, extended information is displayed: Device name/description, device type, serial number (for mass storage devices), the date/time that device was added, VendorID, ProductID, and more...

The primary use for this utility is so you can easily identify which USB hub and port the FLEX-1500 is connected to in your computer. It is best that the FLEX-1500 not share a USB hub with other devices, because connecting a lower speed USB device into the same hub with a higher speed device may lower the performance of the USB Hub.

The USBDeview utility comes as both a 32 and 64-bit application and works with all versions of  Window except Win98, so make sure you get the one that is appropriate for the operating systems installed on your computer. You can download either version from the USBDeview product home page located towards the bottom.

Download and unzip the USBDeview utility to a folder on your computer.  Refer to the application's read-me file for information on running and using USBDeview.

NOTE:  This utility allows the user to uninstall USB devices that you previously used and disconnect USB devices that are currently connected to your computer. Use these features with caution. In order to disable/enable/uninstall USB items under Vista or Win7 with UAC turned on, you should right click on USBDeview and choose 'Run As Administrator'. In order to disable/enable USB items on x64 systems, you must use the x64 version of USBDeview.

Using USBDeview

  • Start the USBDeview Utility
  • From the Option menu option, un-select Display Disconnected Devices. This will make USBDeview show only the currently connected USB devices.
  • Locate the FLEX-1500 by finding the entry that has the VenderID=2192 and the ProductID=150x
  • To the right locate the Hub/Port column.  This will show the USB hub (controller) and port where the FLEX-1500 is connected.

In the example shown below, the FLEX-1500 is connected to USB hub is #4 and the Port is #2 and no other devices are connected the hub #4.  Refer to the information in red box.


If the FLEX-1500 is sharing a USB hub with other connected devices, you can plug the FLEX-1500 into a different USB port while the SDR is powered up and the information will dynamically update in the USBDeview viewer.

The Windows Device Manager Method.

Open device manager (Start | Control Panel | System | Hardware | Device Manager or right-click My Computer | Manage. Then in left column click Device Manager).  Follow the below steps to see what devices are connected to your USB ports:

  1. Click View at the top of device manager and click Devices by Connection.
  2. Click the [+] or [>] next to ACPI Multiprocessor PC.
  3. Click the [+] or [>] next to Microsoft ACPI-Compliant System.
  4. Click the [+] or [>] next to PCI Bus or AMD PCI Express Filter Driver.
  5. Click the [+] or [>] next to each one of the USB Controller listings to display the Root Hub (See the screenshot below.  The exact controller listings can vary based off the controller manufacturer such as Standard Enhanced PCI to USB Host Controller, Standard OpenHCD USB Controller,  Intel, VIA, SIS, NEC, OpenHCD, etc.)
  6. Click the [+]  or [>] next to USB Root Hub under each USB controller listing to display the connected devices or USB Composite Device.
  7. Click the [+]  or [>] next to USB Composite Device under the USB Root Hub listing to display the connected devices.
  8. Look for the FLEX-1500 Software Defined Radio device. No other device or USB Composite Devices should be listed under the USB Controller.

You may have to expand all of the controller and root hub listings to find the USB Controller and Root Hub your device is connected to.  See the screenshot below for an example of what you should see.

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