The PCI2S48515 2-Port PCI Serial Adapter Card (RS422S485) with 1615 UART adds two DB9 RS422S485 serial ports, using a single PCI expansion slot. The PCI serial card offers a high performance 16C15 UART and supports both 2-wire and 4-wire RS485 modes. The card delivers an efficient single-chip design and a large 256-byte transiteceive FIFO buffer that work together to provide high-speed serial communication while reducing the overall load on the system CPU. With the included standard and low profile/half-height brackets, this PCI serial expansion card suits a broad range of system form factors, and is a perfect addition for connecting RS422/485 serial devices to a host computer. For added versatility, the RS422S485 adapter is able to accommodate 3.3 or 5V PCI/PCI-X slots. Backed by a StarTech.com lifetime warranty and free lifetime technical support. The StarTech.com Advantage - Much larger FIFO buffer than standard serial cards (256 byte vs. 32 or 64 byte) minimizes data loss and optimizes host efficiency - A simple jumper change allows you to select either RS422 or RS485 serial interface formats specific to your application - Standard and low profile/half-height bracket included, ensuring easy installation into almost any system