StarTech.com 4-port PCI Express RS232 Serial Adapter Card - PCIe to Serial DB9 RS-232 Controller Card - 16950 UART - Windows, macOS, Linux

$138.99 Regular price

This PCI Express RS232 serial adapter card lets you add four RS232 (DB9) serial ports to your computer through a PCI Express (PCIe) slot, as if they were native serial ports. The 4 port PCIe serial card enables you to interact with serial devices, such as card readers, printers, PIN pads, and modems, at speeds of up to 921.6Kbps. Maximum Compatibility

With broad OS support, including for Windows and Linux, this multiport PCI E serial card is easy to integrate into mixed environments. The card comes pre-configured with a full-sized bracket, and includes an optional low-profile bracket, so installation is easy regardless of the case form factor. This expansion card is a direct replacement for PEX4S952.

Experience Optimal Technology

This PCIe to serial adapter supports the following features:

  • Industry standard 16950 UART compatible
  • Supports max baud rate of up-to 921.6Kbps
  • Provides 5/12V power output on Pin 9 when external power is connected
  • 256-byte depth FIFO cache per transmitter and receiver
  • Supports 9, 8, 7, 6, 5 data bits (one per port)
  • Asix AX99100 chipset
  • Base PCI Express 1.1 compliant
The Choice of IT Pros Since 1985

StarTech.com conducts thorough compatibility and performance testing on all our products to ensure we are meeting or exceeding industry standards and providing high-quality products to IT Professionals. Our local StarTech.com Technical Advisors have broad product expertise and work directly with our StarTech.com Engineers to provide support for our customers both pre and post-sales.

PEX4S953 is backed by a StarTech.com lifetime warranty and free lifetime technical support.


  • STARTECH.COM ADVANTAGE: IT professionals choice for over 30 years; PCI-e RS232 Serial expansion card is backed for life by StarTech.com, incl. free 24/5 North America based multi-lingual tech support
  • VERSATILE APPLICATIONS: For standard profile desktop/servers with uses in point of sale terminals, PLCs, control/automation in factories, scientific sensors, medical equipment, scanners, oscilloscope
  • STANDARD PROFILE & LOW PROFILE BRACKET: PCI Express RS232 serial adapter card has standard bracket pre-installed & 1x low profile bracket incl for versatile install; Supports Windows XP and up & Linux
  • OPTIONAL CONFIGURABLE POWER: PCIe multiport serial card provides 12v, 5v, or none through pin 9 w/up to 2A total; Each of the 4 ports are individually configurable; DB44 to 4x DB9 breakout cable incl
  • 4 PORT SERIAL CARD: Serial controller card w/ 16950 UART based on ASIX AX99100, allows 4x DB9 ports w/bi-directional RS232 speeds up to 921.6Kbps per port, available 256 byte FIFO buffer