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 adapter 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 adapter card (pex2s553) is compatible with a broad range of operating systems including windows 2000/xp/2003/vista/windows 7/server 2008 r2 (32 and 64 bit), linux kernel 2.6.11 and up, and mac os 10.4 and above. plus, the serial card includes an optional half-height/low profile bracket that allows the card to be installed in any pci express slot, regardless of the size of the computer case. this product is a replacement for our pex2s552 card. backed by a startech.com lifetime warranty and free lifetime technical support. features two high speed rs232 serial ports with support for data transfer rates up to 460.8 kbps includes half-height/low 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 warranty lifetime bus type pci express carton quantity 50 color green connector types 2 - db9 male maximum date transfer rate 460.8 kbps note selectable power output on pin 9 of the serial port number of ports 2 product height 20 product length 105 product weight 63.5 product width 120 shipping (package) weight 0.42 lb 0.19 kg supports x1, x2, x4, x8, x16(lane) card type low / standard profile humidity 585% rh operating temperature -20c to 85c (-4degf to 185f) storage temperature -40c to 85c (-40degf to 185f) chipset id moschip mcs9922cv-aa os compatibility dos, windows 95/ 98se/ 2000/ xp(32/64bit)/ server 2003(32/64bit)/ vista(32/64bit)/ 7(32/64bit)/ server 2008 r2, linux, and mac os 10.4.x and up windows xp embedded/ pos ready 2009/ embedded system 2009 os/ ce 5.0/ ce 6.0