Add 4 RS-232 serial ports to your standard or small form factor computer through a PCI Express expansion slot
The PEX4S553 4-Port Native PCI Express RS232 Serial Adapter Card with 16550 UART lets you add 4 RS232 (DB9) serial ports, using a single PCI Express expansion slot.
Based on a native single-chip design, this 4-port serial adapter card allows you to harness the full capability offered by PCI Express (PCIe), while reducing the load applied to the CPU by as much as 48% over conventional bridge-chip serial cards.
The RS232 Serial Adapter Card includes 4 half-height/low-profile brackets, allowing the card to be installed into almost any PC case, regardless of form factor.
Backed by a StarTech.com Lifetime warranty and free lifetime technical support.
The StarTech.com Advantage
- Native single-chip, single lane PCI Express chipset delivers true PCIe performance, up to 48% more efficient than bridge chip designs
- Standard and low profile/half-height brackets included to ensure fitment in any system

Technical details
Sustainability certificates	RoHS
System requirements
Windows operating systems supported	Windows 10, Windows 10 Education, Windows 10 Education x64, Windows 10 Enterprise, Windows 10 Enterprise x64, Windows 10 Home, Windows 10 Home x64, Windows 10 Pro, Windows 10 Pro x64, Windows 2000, Windows 7, Windows 7 Enterprise, Windows 7 Enterprise x64, Windows 7 Home Basic, Windows 7 Home Basic x64, Windows 7 Home Premium, Windows 7 Home Premium x64, Windows 7 Professional, Windows 7 Professional x64, Windows 7 Starter, Windows 7 Starter x64, Windows 7 Ultimate, Windows 7 Ultimate x64, Windows 7 x64, Windows 8, Windows 8 Enterprise, Windows 8 Enterprise x64, Windows 8 Pro, Windows 8 Pro x64, Windows 8 x64, Windows 8.1, Windows 8.1 Enterprise, Windows 8.1 Enterprise x64, Windows 8.1 Pro, Windows 8.1 Pro x64, Windows 8.1 x64, Windows 95, Windows 98SE, Windows Vista Business, Windows Vista Business x64, Windows Vista Enterprise, Windows Vista Enterprise x64, Windows Vista Home Basic, Windows Vista Home Basic x64, Windows Vista Home Premium, Windows Vista Home Premium x64, Windows Vista Ultimate, Windows Vista Ultimate x64, Windows XP Home, Windows XP Home x64, Windows XP Professional, Windows XP Professional x64
Mac operating systems supported	Mac OS X 10.10 Yosemite, Mac OS X 10.4 Tiger, Mac OS X 10.5 Leopard, Mac OS X 10.6 Snow Leopard, Mac OS X 10.7 Lion, Mac OS X 10.8 Mountain Lion, Mac OS X 10.9 Mavericks
Linux operating systems supported	Y
Server operating systems supported	Windows Server 2003, Windows Server 2008 R2, Windows Server 2012, Windows Server 2012 R2, Windows Server 2016, Windows Server 2019
Other operating systems supported	Windows Embedded POSReady 2009, Windows Embedded Standard 2009, Windows XP Embedded
Ports & interfaces
Host interface	PCIe
Output interface	Serial
Serial ports quantity	4
Serial interface type	RS-232
Weight & dimensions
Width	130 mm
Depth	120 mm
Height	19 mm
Weight	74 g
Operational conditions
Operating temperature (T-T)	0 - 50 °C
Storage temperature (T-T)	-20 - 60 °C
Operating relative humidity (H-H)	5 - 85%
Packaging data
Quantity	1
Mounting brackets included	Y
Drivers included	Y
Manual	Y
Package width	141 mm
Package depth	170 mm
Package height	30 mm
Package weight	230 g
Design
Internal	Y
Mean time between failures (MTBF)	26280 h
Certification	CE, FCC, REACH
Features
Chipset	ASIX - MCS9904CV-AA
Baud rate	128 Kbit/s
FIFO (First In, First Out)	256 B
Data bits	5, 6, 7, 8
Logistics data
Harmonized System (HS) code	84733020