The StarTech PEX2S553 is a high-quality 2-port PCI Express RS232 serial adapter card designed to add reliable DB9 serial connectivity to your desktop or server system. Featuring the ASIX MCS9922CV-AA controller with 16550 UART technology, this card supports bi-directional RS232 communication speeds up to 460.8 Kbps per port, and includes a 128-byte FIFO buffer for optimized data flow. It offers individually configurable power supply through pin 9 on each port with adjustable 12V, 5V, or no power options to best suit your peripheral requirements.

Ideal for professional IT environments and industrial applications, the PEX2S553 adapts seamlessly to point of sale terminals, factory PLCs, scientific instruments, medical devices, scanners, and oscilloscopes. Its versatile design comes equipped with a pre-installed standard bracket and two low-profile brackets, enabling installation in both standard and small form factor PCs.

Compatible with Windows, macOS, and Linux operating systems, this plug-and-play serial adapter ensures broad OS support with stable drivers provided. Built for durability and backed by StarTech's lifetime warranty and 24/5 multilingual technical support, the PEX2S553 is the go-to serial expansion card for professionals requiring robust and flexible RS232 connectivity solutions.

Key Features:

• Dual external RS232 DB9 serial ports with 16550 UART


• PCI Express plug-in card compatible with standard and low-profile slots


• Supports configurable 12V, 5V, or no power on each serial port


• Compatible with Windows, Mac, and Linux systems


• Ideal for industrial, scientific, and POS terminal applications


• Includes standard bracket and two low-profile brackets for flexible installation


• Lifetime warranty and free 24/5 multilingual technical support from StarTech