Drivers for FTDI adapters

This guide applies to adapters with an FTDI chipset: CM327, ELS27.

Three steps are required: install the driver, identify the chipset and set up the correct driver. The last two steps are needed because Windows otherwise assigns the adapter a driver of its own and sticks with it.

Step 1: install the driver

Download the FTDI driver (VCP) and install it before plugging in the adapter.

Download FTDI driver

Checksum (SHA-256): a8654caa76151e92161e2767294337039189ac3bab3a794dbac791cd1901172b

Step 2: identify the chipset and set up the driver

Plug in the adapter and open Device Manager. Under “Ports (COM & LPT)” an FTDI adapter appears as “USB Serial Port (COM…)”.

Right-click that entry → “Update driver” and select the FTDI driver you installed.

Step 3: apply the fix

FTDI fix: speed up reading

This adapter uses an FTDI chip. Its Windows driver collects incoming data for up to 16 ms before passing it on — that slows reading down considerably. The fix sets the latency to 1 ms.

It sets the adapter to the highest read and write speed.

Run as administrator. Afterwards unplug the adapter once and plug it back in.

Download FTDI fix

Checksum (SHA-256): b59f2095d0761a2770d77894391c273225d6cef3890ba97806973a53be5d1043

Note: Windows warns on first launch

The fix is a small program without a signing certificate. Windows therefore shows “Windows protected your PC”. Use “More info” and “Run anyway” to start it.

To be certain, verify the file first: run certutil -hashfile <file> SHA256 at the command prompt and compare the result with the checksum above.