Pira.cz Technical Forum
FM Analysis => P275 FM Analyzer => Topic started by: Gordon_Waters on July 12, 2026, 04:58:56 am
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I need to install the FM 275 onto Win 11 Home laptop, but am unable to get a com port to show up.
I have installed the usb drivers from https://ftdichip.com/drivers/vcp-drivers/ but I do not get a com port shown.
Any assistance would be great.
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You don't mention which version of the P275 FM Analyzer you have, so I'll answer in general.
We're not aware of any compatibility issues with Windows 11. We use Windows 11 ourselves and all of our USB products communicate in the same way. The driver is included with Windows as standard, or Windows installs it itself. There is no need to install the driver manually.
The virtual COM port is only present while the analyzer is connected and powered on. This is normal Windows behavior, regardless of the Windows version. (Windows remembers the previously assigned COM port number, but it is only available while the device is connected.)
Could you please check the following?
- Is the analyzer powered on when you connect it? Windows only creates the COM port while the device is connected and powered. In other words, is the power from the USB cable working? If not, the USB cable or port on the PC is faulty.
- Does anything new appear in Windows Device Manager after connecting the analyzer? Please check both Ports (COM & LPT) and Universal Serial Bus controllers. If you see an Unknown device or a device with a yellow exclamation mark, please let us know.
- Please try a different USB cable or a cable supplied with the device (if this is that case).
- If possible, also try a different USB port (preferably directly on the laptop, not through a USB hub).
- If you have another Windows PC available, please check whether the analyzer is detected there.
If nothing at all changes in Device Manager when the analyzer is connected or disconnected, Windows is not detecting the USB device at all. In that case the problem may be the USB cable, USB port, or a hardware issue.