Features two 16c550 uart serial ports pci 32-bit, pio mode with 133mb/s bandwidth pci irq sharing feature eliminates irq conflicts supports both 5v and 3.3v standard pci slots two db9-male connectors (or 2 internal headers) works with all types of i/o peripherals supports windows 95/98/me, nt, 2000, xp, 2003, 7, 8, vista, & linux .