FTDI's own vendor ID (VID) may be used by manufacturers using FTDI devices in their products, but must be used in conjunction with a product ID (PID) issued by FTDI.
FTDI can allocate a block of 8 PIDs for use with the FTDI VID (0x0403) free of charge. To request a block of PIDs for use with FTDI's VID, contact FTDI Support quoting the following informaton:
Please note that a PID issued to you by FTDI must only be used with FTDI's VID.
In addition, the driver INF/INI files must be amended to reflect the changed PID.