Use a single pci slot to add two serial and one parallel portscompatible with most rs232 peripherals the serialparallel combo pci card with two external serial db9 ports is an ideal solution for attaching two serial devices modems barcode scanners printers and more and a parallel db25 port through a single pci card and two open rear expansion slots its two high speed 16c550 uart serial db9 com ports fully support pci irq sharing even if accessed simultaneously to help save valuable res