Hello,
The description in the chip will be shown when the device is initially connected but in device manager Windows will replace the name with those taken from the inf files of the driver (e.g. USB Serial Port). This will happen for other USB devices too including our other USB-serial chips.
To change the string, you would need to edit the inf files but the latest versions of Windows have these digitally signed and so if you edit these you would not be able to install the driver in normal user mode on Windows. If your device was to be distributed to customers you would normally get a custom PID and program the device with this and have a driver edited to match your PID along with the new strings. You would then get reseller rights from Microsoft to re-sign your driver. Microsoft require you to purchase an EV certificate and so this would involve costs.
An alternative is to keep the VID/PID and the inf file as default, but to open the device using our D2xx driver as you can open by description. This means your application can find the device with no effort by the user. As a trade-off you would not get your device name in the device manager but on the other hand it saves cost and time. But if your main objective is to make the device easy to find and open with minimal hassle to users then this might be a good solution.
If you already have an application on Windows that uses VCP, you can even open the device by description in D2xx, check the COM port number via FT_GetCOMPortNumber and then close it and pass this to your VCP program.
Best Regards, FTDI Community