IO CREST

IO CREST 2-Port PCI Express RS232 Serial Adapter Card

Name: 2-Port PCI Express RS232 Serial Adapter Card - PCIe RS232 Serial Host Controller to Dual Serial DB9 Ports with Low Profile Bracket
Brand: IO CREST
SKU: B00B5L9P36

Bottom line: The IO CREST 2-Port PCI Express RS232 Serial Adapter Card: Adds two full RS-232 DB9 ports via a single PCIe x1 slot; main trade-off: RS-232 only, no RS-422/485 industrial signaling.

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By Mike Perry, Founder & Editor-in-Chief · Listing data updated 2026-10-06

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. About the author →

Pros & Cons

Pros

✓ Adds two full RS-232 DB9 ports via a single PCIe x1 slot
✓ Ships with both full-height and low-profile brackets for any case
✓ 16C450/550/extended-550 UART support for legacy serial gear
✓ Baud rates from 50bps up to 16Mbps per port
✓ Windows and Linux support (kernel 2.6.11 and newer)

Cons

✗ RS-232 only, no RS-422/485 industrial signaling
✗ DB9 connectors only, no DB25 breakout included
✗ Requires a free PCIe slot, not an option for laptops
✗ Legacy PCIe 1.0a spec, no modern revision listed

Manufacturer description

Add 2 RS-232 DB9 serial ports to your full height or low profile computer through a PCI Express X1 slot with IOCrest SI-PEX15037 PCI-Express X2 serial controller card. The RS232 serial adapter card is compatible with a broad range of operating systems, including Windows and Linux (kernel 2.6.11 and up). plus, the adapter card includes an optional half-height/low profile bracket that allows the card to be installed in virtually any computer case.

SpecPicks Verdict

SpecPicks scored IO CREST 2-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. IO CREST'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

Fully compliant with PCI-E base Specification, Revision 1.0A
Support for D1, D2, D3hot and D3cold
Utilizes 100-MHz Differential PCI-E common reference Clock
2 16C450/550/extended 550 compatible UART
Bi-directional speeds from 50bps to 16Mbps/port
Fully Compliant with PCI-e Base Specification, Revision 1.0a

Full Specifications

Brand	IO CREST
Style	Double Serial DB9 Port PCIe x1
Style Name	Double Serial DB9 Port PCIe x1
Unit Count	2 Count
Model Number	SI-PEX15037
Built-In Media	2 Serial Ports Pci-E Controller Card^2X Single Port Low Profile Brackets^Full Bracket For 2 Com Ports^User Manual^Driver Mini Cd
Mfr Part Number	SI-PEX15037
Compatible Devices	Desktop
Hardware Interface	Serial Interface
Warranty Description	3 Year Warranty
Full listing title	2-Port PCI Express RS232 Serial Adapter Card - PCIe RS232 Serial Host Controller to Dual Serial DB9 Ports with Low Profile Bracket

Ready to buy?

2-Port PCI Express RS232 Serial Adapter Card - PCIe RS232 Serial Host Controller to Dual Serial DB9 Ports with Low Profile Bracket is vintage hardware; the used and vintage market on eBay carries most of the live inventory. Prices and condition vary by seller and move in real time, so we link the live listing rather than quote a cached price. It also has an Amazon listing — check it for current price and availability. SpecPicks earns a small commission on qualifying purchases — thank you for supporting independent review work.

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