The PEX2S553 PCI Express serial card lets you turn a PCI Express slot into 2 RS232 (DB9) serial ports Based on a native single chip design (no bridge chip) this 2-port serial Adaptor card allows you to harness the full capability offered by PCI Express (PCIe) and reducing the load applied to the CPU by as much as 48 over conventional serial cards The RS232 Serial Adaptor Card (PEX2S553) is compatible with a broad range of operating systems including Windows 2000XP2003VistaWindows 7Server 2008 R2 (32 and 64 bit) Linux Kernel 2611 and up and MAC OS 104 and above  Two high speed RS232 serial ports with support for data transfer rates up to 4608 Kbps  Compliant with PCI Express base specifications revision 10a  Includes half-heightlow profile mounting bracket  Selectable power output on pin 9 for the serial port  128-byte deep FIFO per transmitter and receiver  Native single-chip single lane PCI Express  Automated out-of-band flow control using CTSRTS and DSRDTR  Automated in-band software flow control using programmable XonXoff in both directionsDepth 105 cmForm Factor PCI CardHeight 2 cmNumber of Ports 2 port(s)Port Connector DB-9Product Type Serial Port CardWarranty Lifetime warrantyWeight 063 kgWidth 635 cm