This breakout board pairs an SP3485 RS-485 transceiver with an FT232RL USB UART IC to convert a USB stream to RS-485. The SP3485 is a half-duplex transceiver, so it can only communicate one way at a time, but it can reach transmission speeds of up to 10Mbps. The RTS pin of the FT232RL is connected to the transmit and receive enable inputs of the SP3485, this line is used to control the transmission mode of the RS-485 transceiver. With the proper drivers installed, the FT232RL will enumerate as a virtual COM port; the drivers are available for Windows, Mac and Linux. This breakout board includes the SP3485, FT232, TX/RX/RTS LEDs, miniB USB connector, filter capacitors, and other components shown on the schematic. We've broken out the RS485 output to three different connections: (1) an , (2) a , and (3) a 3-pin 0.1" pitch header; none of these output connectors come populated. Project description, more information and ordering can be found at https://www.sparkfun.com/products/9489 SP3485 Datasheet: http://www.sparkfun.com/datasheets/Components/General/sp3485CN-LTR.pdf FT232RL VCP Drivers: http://www.ftdichip.com/Drivers/VCP.htm