StarTech.com 4 Port PCI RS232 Serial Adapter Card with 16550 UART (PCI4S550) Serial ports are on the included dongle cable, so only a single slot is occupied in the system case, making it ideal for space sensitive installations Broad operating system compatibility with support for Windows or Linux makes this card perfect for installation into mixed environments Easy plug and play installation fits any standard profile PCI slot Includes 4-port RS232 breakout cable IRQ sharing 16 byte FIFO buffer ensures fast data transfers while multitasking