One of the most basic operations with the FT232R, FT2232 (UART mode) and FT232B devices is setting a Baud rate. This application note describes the various ways that this can be done. It also describes how to use non-standard baud rates with FTDI's USB-Serial IC devices, including a technique called 'aliasing' - where one Baud rate is substituted by the driver in place of another baud rate.
The second generation FT232B USB UART IC added additional granularity to the divisor used to generate the device Baud rate. This allows a much larger number of baud rates to be used with the FT232B when compared to its predecessor, the FT8U232AM.