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StarTech 4-Port PCI Express RS232 Serial Adapter Card, TAA (PEX4S953) | PCIe RS232 Serial Host Controller Card, PCIe to Serial DB9 Card, 16950 UART, Windows & Linux, Expansion Card
StarTech.com

StarTech.com StarTech 4-Port PCI Express RS232 Serial Adapter Card

Bottom line: The StarTech.com StarTech 4-Port PCI Express RS232 Serial Adapter Card is a specs-and-price decision rather than a crowd-consensus one in the expansion cards category, priced around $103.99 on Amazon as of 2026-10-06. Check the specification table below against one or two close alternatives — on price and spec fit, not on star ratings.

$103.99

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Buy on Amazon — $103.99 Compare to similar expansion cards

By , Founder & Editor-in-Chief · Listing data updated

Mike Perry — Hardware researcher since 2014. For retro PC hardware and period-correct parts, synthesises manufacturer documentation, community compatibility lists and marketplace listings rather than first-hand lab testing. Core beat: GPU performance across gaming, rendering, and local-LLM inference.

*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.

Pros & Cons

Pros

  • ✓ Backed by StarTech.com's warranty and support channels

Cons

  • ✗ Confirm socket / form-factor / power-rating compatibility against your build before ordering
  • ✗ Price, stock, shipping and returns are set by the retailer and may have changed since this page was last updated

Manufacturer description

This multiport 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 4 port PCI E serial card is easy to integrate into mixed environments. The PCI E expansion slot comes pre-configured with a full-profile bracket, and includes optional…

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SpecPicks Verdict

SpecPicks scored StarTech.com StarTech 4-Port PCI Express RS232 Serial Adapter Card using a rating × review-volume × price-fit model applied to published specs and reviews across the expansion cards category. StarTech.com's expansion cards lineup sits within the broader category mid-tier; price and specs are the deciding factors over brand loyalty here. Judge it on the specification table and the price rather than on sentiment: check the figures that decide your use case, then put it side-by-side with two or three close alternatives in the Compare tool before clicking through.

Common buyer scenarios for expansion cards of this kind: matching it to an existing build, replacing a failing part, or upgrading from a previous-generation equivalent. Check the spec table below against your current setup — particularly socket / form-factor / power-rating fields — and confirm compatibility on the retailer's listing before purchase. Prices and stock are set by the retailer and may have moved since this page was last updated.

Key Features

  • 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; Upgraded version of our popular Serial card PEX4S952
  • 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
  • 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
  • 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

Full Specifications

BrandStarTech.com
StyleFull Profile
Style NameFull Profile
Unit Count1 count
Model NumberPEX4S953
CompatibilityLinux
Built-In Media4 Port Full Profile Serial Card Low Profile Bracket Break-out Cable Quick Start Guide
Item Type NameMultiport Serial Adapter
Mfr Part NumberPEX4S953
Compatible DevicesDevices with PCI Express slot requiring RS232 serial communication
Hardware InterfacePCI
Warranty DescriptionLifetime
Item Dimensions L x W x H3"L x 2.5"W x 0.6"H
Global Trade Identification Number00065030888257
Full listing titleStarTech 4-Port PCI Express RS232 Serial Adapter Card, TAA (PEX4S953) | PCIe RS232 Serial Host Controller Card, PCIe to Serial DB9 Card, 16950 UART, Windows & Linux, Expansion Card

Ready to buy?

StarTech 4-Port PCI Express RS232 Serial Adapter Card, TAA (PEX4S953) | PCIe RS232 Serial Host Controller Card, PCIe to Serial DB9 Card, 16950 UART, Windows & Linux, Expansion Card is listed on Amazon. Price, availability, shipping and returns are set by Amazon and its sellers — check the listing for current terms. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

Buy on Amazon — $103.99

*Price sourced from Amazon.com. Last updated 2026-10-06. Price and availability subject to change.

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StarTech 4-Port PCI Express RS232 Serial Adapter Card, TAA (PEX4S953) | PCIe RS232 Serial Host Controller Card, PCIe to Serial DB9 Card, 16950 UART, Windows & Linux, Expansion Card
$103.99
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