This is a new version of the FTDI breakout board features an Atmega8U2 programmed as a USB-to-serial converter, the same chip found on the Arduino Uno. The 8U2 firmware uses the standard USB COM drivers, and no external driver is needed. However, on Windows, a .inf file is required.
The USB Serial Adapter has an onboard mini-USB connector and 5 pins including RX (for receiving data from the computer) and TX (for transmitting data). 5V or 3.3V(selcted by switching the jumper), Ground and a Reset pin are also exposed. Status lights include RX and TX activity. The adapter can easily connect to the Arduino Ethernet, Mini, Mini Pro, LilyPad, LilyPad Simple, and Fio.