Add 1 parallel port & 2 RS-232 serial ports to your standard or low-profile desktop computer through a PCI Express expansion slot. The PEX2S5521P 2S1P PCI Express Card turns a PCI Express slot into two RS232 (DB9) serial ports & one Parallel port. The adapter card features a native PCI Express single chip design that means that you can take advantage of full PCI Express capability, providing enhanced speed & reliability while reducing the load applied to the CPU by as much as 48% over conventional serial cards which use a bridge chip design.