The other pins are only necessary if you're using a device with flow control or specific RS-232 serial needs. The most important and commonly used serial pins are D0 and D1 for the TX and RX pins. This is an optional pin that is sometimes used in RS-232 serial communication. Like DTR, this is another optional pin for flow control in RS-232 serial connections. Another optional pin for flow control in RS-232 serial connections. Like RTS, this is an optional pin for flow control. This is an optional pin for flow control of serial connections. This pin is the serial data input for the FT232H chip and should be connected to the TX or transmist pin of a serial device. This pin is the serial data output by the FT232H chip and should be connected to the RX or receive pin of a serial device. When used as a serial UART the FT232H breakout pins have the following serial functions:

This means the FT232H breakout can used to safely talk to an Arduino's 5 volt serial ports, and a Raspberry Pi or BeagleBone Black's 3.3 volt serial ports! It's safe to use with both 3.3 volt and 5 volt signals.

This is great for talking to a serial device like an Arduino from your computer. Out of the box the FT232H is configured to act just like an FTDI friend USB to serial UART converter.

Ft232r usb uart driver