Dual Port PCI Express RS-232 DB9 Serial Port Card
4.5Editor score
ASIX AX99100 chipset
Compatible with Windows and Linux
Fits x1 to x16 slots
In this guide
Modern desktop computers often lack legacy serial ports needed for industrial equipment, POS systems, and specialized sensors. A Pcie Serial Port Card solves this by adding reliable RS-232 connectivity directly through your motherboard.
We analyzed ten highly rated expansion cards based on chipset quality, bracket options, and driver support across multiple operating systems. Our goal is to help you find the most stable and compatible solution for your specific hardware setup.
Each entry below details key specifications, real-world applications, and installation notes to ensure a smooth upgrade process. Please note that availability and pricing may change frequently on retailer sites, so verify current details before purchasing.
Top 3 Picks for Best Pcie Serial Port Card
StarTech 2-Port PCI Express RS232 Serial Adapter Card
4.9Editor score
256-byte FIFO buffer
Configurable power pin 9
Low and full profile brackets
StarTech 1-Port PCI Express RS232 Serial Adapter Card
4.2Editor score
Up to 921.6Kbps speed
TAA compliant for government
9th data bit support
Top 10 Best Pcie Serial Port Card in 2026 Compared
The following table provides a side-by-side comparison of all ten selected expansion cards, highlighting their core specifications and compatibility features to help you make an informed decision quickly.
ProductsSpecificationsEditor scorePrice
Editor's Choice
PCIE-SE2 2-Port PCI Express
2 x DB9 ports
ASIX AX99100 chipset
Windows and Linux support
Low and full brackets
4.5Editor score
Editor's Choice
StarTech 1-Port PCI Express RS232
1 x DB9 port
16950 UART support
256 byte FIFO buffer
Configurable power options
4.2Editor score
Best Budget
Dual Port PCI Express RS-232
2 x DB9 ports
ASIX AX99100 chipset
32 and 64 bit OS
X1 to X16 slots
4.5Editor score
StarTech 2-Port PCI Express RS232
2 x DB9 ports
16950 UART support
Individually configurable ports
TAA compliant model
4.9Editor score
StarTech 2-Port PCI Express Serial
2 x DB9 ports
460Kbps transfer rate
Plug and play IRQ
Standard and low bracket
4.2Editor score
PCIe Combo Serial Parallel Expansion
1 Serial and 1 Parallel
WCH382 Chipset
IEEE 1284 controller
Up to 1.5Mbps parallel
4.3Editor score
2-Port PCIe RS-232 DB9
2 x DB9 ports
ASIX AX99100 chipset
Multi-platform driver support
Two low profile brackets
3.7Editor score
VANTEC 2-Port Serial RS-232
2 x Serial ports
RS-232 PCIE Host
Compact design layout
Desktop PC compatible
5.0Editor score
2-Port PCIe Serial Expansion
2 x DB9 ports
WCH382 Chipset
Industrial quality connectors
Windows and Linux OS
4.2Editor score
Single Port PCI Express x1
1 x DB9 port
MCS9922 Chipset
250Kbps transfer rate
Low profile design
4.3Editor score
1. PCIE-SE2 – Best Value Dual Port Solution
PCIE-SE2 2-Port PCI Express RS-232 DB9 Serial Port Card
ASIX AX99100 solution
256-byte FIFO depth
X1 to X16 compatible
Standard and low brackets
The PCIE-SE2 card stands out as a highly rated solution for adding two serial ports to modern desktop systems. With a strong user rating of 4.5 stars, it demonstrates reliability across various industrial and office environments.
Pros
- Affordable dual port option
- Wide OS compatibility
- Reliable ASIX chipset
- Flexible bracket inclusion
Cons
- Driver installation required
- Linux needs source compile
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Its core strength lies in the ASIX AX99100 chipset which supports a 256-byte FIFO buffer for stable data transmission. The card works seamlessly on Intel AMD and ARM platforms and offers broad operating system support from Windows XP through Windows 11.
While it offers great value, users should note that driver installation is mandatory on Windows systems and Linux users may need to compile source code from the provided CD. This minor setup step ensures optimal performance on your specific hardware.
This card is ideal for small businesses or technicians who need reliable serial connectivity for POS systems or control devices without breaking the budget. Its flexible bracket design ensures it fits both standard and slim chassis configurations.
Wide Hardware Platform Support
The chipset ensures stable performance across Intel AMD and ARM hardware platforms for diverse system builds.
Flexible Installation Options
Includes both standard and low profile brackets to fit standard PCs and slim form factor cases easily.
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2. StarTech PEX1S953LP – Best Premium Single Port
StarTech 1-Port PCI Express RS232 Serial Adapter Card
16950 UART based
Up to 921.6Kbps
Configurable pin 9 power
TAA compliant model
This StarTech card is engineered for users who demand high performance and compliance standards in their serial communication setups. It delivers robust speeds up to 921.6Kbps making it suitable for data intensive serial applications.
Pros
- High speed data transfer
- Government compliant TAA
- Configurable power output
- Reliable StarTech brand
Cons
- Single port limitation
- Higher price point
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The card features a 16950 UART based controller with a 256 byte FIFO buffer ensuring data integrity during high volume transfers. A standout feature is the optional configurable power through pin 9 allowing you to supply power to connected devices directly.
Though it only provides one port the build quality and compliance features justify the investment for critical infrastructure. The included brackets allow for easy installation in standard and low profile server racks or desktop towers.
Choose this card if you need TAA compliance for government projects or require stable power options for specialized serial devices. It is a premium choice for professional environments where reliability is paramount.
High Speed Data Transfer
Supports bi-directional RS232 speeds up to 921.6Kbps per port for fast and reliable data communication.
Optional Configurable Power
Provides choice of 12v 5v or none through pin 9 with up to 2A total to power connected peripherals.
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3. Dual Port PCI Express – Best Budget Dual Port
Dual Port PCI Express RS-232 DB9 Serial Port Card
2 independent RS232 ports
ASIX AX99100 chipset
Windows XP to 11 support
Full and low bracket included
This dual port card offers an exceptional balance of performance and affordability for users needing multiple serial connections. It provides two independent RS232 ports which significantly expand your system's connectivity for various peripherals.
Pros
- Affordable pricing
- 256-byte FIFO transfer
- Wide OS support
- Dual port flexibility
Cons
- Driver setup required
- Basic build materials
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Utilizing the ASIX AX99100 solution it supports 256-byte depth FIFO transfer on-chip for stable data handling across Intel AMD and ARM platforms. The card is compatible with a wide range of Windows versions and Linux kernels with source code available.
While it requires driver installation from the Mini-CD it works reliably once configured. The inclusion of both full-size and low-profile brackets makes it versatile for different PC chassis types including 2U computers.
This card is perfect for budget-conscious buyers who need reliable dual port capabilities for logistics management or scanner connectivity. It delivers consistent performance without the premium price tag of more branded alternatives.
Advanced Chip Solution
Utilizes ASIX AX99100 solution supporting 256-byte depth FIFO transfer on-chip for reliable data throughput.
Versatile Bracket Design
Comes with full-size and low-profile brackets ensuring compatibility with standard and slim computer cases.
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4. StarTech PEX2S953LP – Best Overall Dual Port
StarTech 2-Port PCI Express RS232 Serial Adapter Card
2 x DB9 ports
16950 UART based
Individually configurable power
TAA compliant model
With a remarkable 4.9 rating this StarTech card is widely considered the top choice for reliable dual port serial expansion. It is a direct upgrade from popular models and offers enhanced performance for demanding industrial applications.
Pros
- Highest user rating
- Individual port power config
- 9th data bit support
- TAA government compliant
Cons
- Higher cost option
- Requires driver setup
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The card features a 16950 UART based controller with bi-directional RS232 speeds up to 921.6Kbps per port. Each of the two ports offers individually configurable power options through pin 9 allowing for tailored power delivery to devices.
It includes both low profile and full profile brackets for versatile installation in standard and low profile desktops or servers. The TAA compliance makes it a suitable choice for government procurement projects requiring strict regulatory adherence.
This card is the best all-round choice for users who need maximum reliability and flexibility in their serial infrastructure. The combination of high speed configurable power and government compliance justifies its position as a top premium option.
Individually Configurable Power
Each of the two ports are individually configurable for power choices of 12v 5v or none through pin 9.
High Speed Communication
Supports bi-directional RS232 speeds up to 921.6Kbps per port with a 256 byte FIFO buffer for stability.
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5. StarTech PEX2S1050 – Best for Industrial Equipment
StarTech 2-Port PCI Express Serial Card
PCIe 1.0a compliant
Up to 460Kbps rate
Plug and play IRQ
Standard and low bracket
This dual port card is designed with maximum compatibility and adherence to industry standards for seamless integration. It meets PCI Express 1.0a specifications ensuring reliable operation in a wide range of system upgrades.
Pros
- Compliant with PCIe standards
- Plug and play support
- Ideal for POS equipment
- Simple installation process
Cons
- Slower transfer rates
- Limited speed options
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The card delivers high-performance serial communication with support for data transfer rates of up to 460Kbps which is sufficient for many legacy devices. It features IRQ sharing and plug-and-play connection for straightforward setup without complex configurations.
Its low-profile serial card design works well in modern compact servers or desktops while maintaining robust connectivity for manufacturing and security devices. The included brackets allow for flexibility in different installation scenarios.
Ideal for users upgrading manufacturing equipment or POS systems this card offers a reliable bridge between modern PCs and legacy peripherals. It prioritizes stability and ease of use over raw speed making it a practical choice for specific industrial needs.
Maximum Compatibility
Ideal for system upgrades in a wide range of applications including manufacturing POS and security devices.
Simple Installation
Features IRQ sharing and supports plug-and-play connection for easy setup without technical expertise.
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6. PCIe Combo Serial Parallel – Best for Dual Legacy Support
PCIe Combo Serial Parallel Expansion Card
1 Serial and 1 Parallel
IEEE 1284 controller
Faster data rates
WCH382 Chipset
This unique expansion card offers the dual capability of adding both a serial and a parallel port to your computer easily. It is specifically designed for users who still rely on legacy parallel printers alongside serial devices.
Pros
- Adds parallel and serial
- 1.5Mbps parallel speeds
- Automatic IRQ selection
- Multi OS support
Cons
- Requires CD driver install
- Specialized use case
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The multi-mode IEEE 1284 compliant controller supports SPP PS2 EPP and ECP modes with data rates up to 1.5Mbps for the parallel port. It automatically selects IRQ and IO address supporting IRQ sharing for hassle-free plug and play functionality.
Driver installation is straightforward by opening the CH38XDRV file on the CD provided with the card. It works on both 32bit and 64bit Windows versions and Linux ensuring broad system compatibility.
Choose this card if your workflow requires connectivity for both printers and serial sensors without purchasing two separate cards. It is a specialized solution that simplifies retro-fitting older equipment into modern desktop environments.
Multi-Mode Controller
Multi-mode IEEE 1284 compliant controller supporting SPP PS2 EPP and ECP for versatile parallel communication.
Plug and Play Support
Automatically selects IRQ and IO address and supports IRQ sharing for easy installation and configuration.
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7. 2-Port PCIe Dual Serial – Fast Data Transfer
2-Port PCIe RS-232 DB9 Serial Port Card
ASIX AX99100 solution
256-byte deep FIFO
Wide OS compatibility
Two low profile brackets
This expansion card is designed to easily add two RS232 DB9 serial ports to desktop PCs or industrial devices via a PCIe slot. It aims to meet various device connection needs with a focus on stable data transmission performance.
Pros
- Stable serial transmission
- Two low profile brackets
- X1 to X16 slots
- Multi-platform support
Cons
- Lower user rating
- Basic bracket options
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It utilizes the ASIX AX99100 solution supporting 256-byte deep FIFO transmission which is compatible with Intel AMD and ARM hardware platforms. The driver is compatible with Windows XP through 11 and several Linux kernel versions for smooth installation.
Comes with a standard full-size bracket and includes two low-profile brackets for perfect compatibility with slim PCs making it versatile for small form factor builds. Ensure your PC has an available PCIe slot before installation.
While the rating is slightly lower it offers a practical solution for expanding connectivity on a budget. It is a solid choice for users needing fast data transfer for logistics management or security systems in smaller enclosures.
Efficient Data Transmission
Utilizes the ASIX AX99100 solution supporting 256-byte deep FIFO transmission for stable serial performance.
Flexible Installation
Includes a full-size bracket and two low-profile brackets ensuring compatibility with various PC case sizes.
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8. VANTEC 2-Port Serial – Reliable Host Card
VANTEC 2-Port Serial RS-232 PCIE Host Card
2-Port Serial RS-232
PCIE Host Card
Compact design layout
Desktop PC compatible
This VANTEC host card offers a straightforward solution for adding two RS-232 serial ports to your desktop PC system. It has maintained a strong user rating indicating reliable performance over time for various legacy connection needs.
Pros
- High user satisfaction
- Reliable host performance
- Compact internal layout
- Standard desktop support
Cons
- Limited product info
- Older product model
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The design focuses on being a dedicated host card which often ensures stable communication channels for connected devices without external dependencies. Its compact layout makes it suitable for standard desktop cases where space might be a constraint.
While detailed technical specifications are not fully listed it is known to support standard serial operations. The simplicity of the product suggests it is built for basic compatibility and reliability rather than advanced features.
Choose this card if you need a trusted brand known for consistent performance in simple serial expansion scenarios. It is ideal for users looking for a no-fuss way to add connectivity for security systems or sensors.
Compact Internal Layout
Compact design layout suitable for standard desktop cases where internal space is a constraint.
Reliable Host Performance
Dedicated host card design ensures stable communication channels for connected legacy devices.
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9. 2-Port PCIe Serial Expansion – Industrial Grade Ports
2-Port PCIe Serial Expansion Card
2 x 16C550 UART ports
WCH382 Chipset
Industrial quality connectors
Windows and Linux support
This expansion card allows for upgrading with additional serial cards to your computer easily using robust industrial grade connectors. It provides two 16C550 Fast UART serial ports that support data transfer rates up to 230400Bps.
Pros
- Industrial grade DB9 ports
- 230400Bps transfer rate
- Automatic IRQ selection
- Plug and play setup
Cons
- CD driver required
- Basic power options
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Plug and play functionality automatically selects IRQ and IO address and supports IRQ sharing for simplified installation. The card is compliant with ExpressCard/34mm Standard and compatible to 1-Lane PCI Express Throughput.
Operating system support covers a wide range of Windows versions and Linux ensuring versatility across different environments. If any problem occurs with the expansion card the support team provides a solution within 24 hours.
Ideal for industrial applications this card offers strong connectivity for automation or control equipment. It balances performance with ease of use making it a solid choice for technical setups requiring reliable COM ports.
Industrial DB9 Ports
Industrial DB9 RS232 COM Ports designed for robust connectivity in demanding environments.
Automatic IRQ Selection
Plug and play automatically selects IRQ and IO address supporting IRQ sharing for easy setup.
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10. Single Port PCIe RS232 – Best Single Port Option
Single Port PCI Express x1 RS232 Serial Adapter Card
MCS9922 Chipset
16C550 UART support
Low profile design
Up to 250Kbps rate
This single port adapter card provides a simple way to add a standard serial DB9 port to a modern PCIe system. It is fully compliant with the PCI-Express base Specification Revision 1.0a ensuring reliable operation.
Pros
- Low profile form factor
- Hardware and software flow control
- 256-byte FIFO depth
- Single lane PCIe support
Cons
- Single port only
- Basic feature set
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The MCS9922 Chipset is compatible with Industrial Standard 16C550 UART and features an On Chip 256-byte Depth FIFO in Transmit. Transfer data rates up to 250Kbps on each port with support for hardware and software flow control.
Designed for single-lane (x1) PCI-Express throughput up to 2.5Gbps this low profile card fits well in compact desktop cases. It supports flexible serial formats including 5 6 7 and 8-bit serial data types.
Choose this card if you only need a single port for a specific device like a modem or scanner. It is a cost-effective solution for systems with limited slots that still require legacy serial connectivity.
Flow Control Support
Supports hardware and software flow control for stable data transmission across serial devices.
Low Profile Design
Low profile form factor fits perfectly in slim PCs and compact desktop cases.
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Buying Guide – How to Choose the Best Pcie Serial Port Card
Selecting the right serial port card involves evaluating several technical factors to ensure it meets your hardware and software requirements without installation issues.
Chipset Quality
The chipset is the brain of the card determining data transfer reliability and OS compatibility. Look for well-known chipsets like ASIX AX99100 or MCS9922 which are known for stable FIFO buffers and broad driver support.
Always choose a card with a verified chipset to avoid connection drops or driver conflicts in your system.
Operating System Support
Check that the card supports your specific version of Windows or Linux. Some cards require driver installation from a Mini-CD or source code compilation for Linux systems which may be challenging for non-technical users.
Verify current driver availability on the manufacturer website before purchase to ensure easy setup on your machine.
Port Count Requirements
Determine how many serial devices you need to connect simultaneously. While most cards offer one or two ports some specialized units offer more. Ensure the card provides enough ports for all your POS or industrial devices.
Select a card with enough ports to avoid daisy chaining issues and simplify your overall cabling infrastructure.
Bracket Compatibility
Modern desktop cases come in standard and low profile sizes. A good card should include both a full-size and a low profile bracket to ensure it fits your specific chassis without requiring custom parts.
Confirm the package includes the correct bracket type for your PC case to prevent installation failures.
Data Transfer Speed
Serial communication speeds vary from standard 115200bps to higher speeds like 921.6Kbps. For industrial devices that transmit large amounts of data a card with a higher speed limit ensures faster performance.
Check the rated maximum speed to match it with the requirements of your connected serial equipment.
Power Requirements
Some serial devices draw power from the card via Pin 9. Cards with configurable power options can supply 12V or 5V directly eliminating the need for external power supplies for those devices.
Choose a card with configurable power if you need to power attached peripherals without extra cables.
PCIe Slot Type
Most cards use a PCIe x1 interface which fits into any x1 x4 x8 or x16 slot on your motherboard. Confirm your computer has an empty slot of the correct size before installation to avoid physical constraints.
Ensure your PC has an available PCIe slot to accommodate the card size and connectivity requirements.
Brand and Warranty
Reputable brands like StarTech often provide better support and warranty terms which can be crucial for industrial use. Check customer reviews and warranty duration to gauge reliability before finalizing your purchase.
Prioritize brands with strong support to resolve any hardware or driver issues quickly.
How to Use and Care for Your Pcie Serial Port Card
Before installing the card shut down your computer and disconnect the power supply to ensure safety. Open the case carefully and locate an available PCIe slot on the motherboard to prepare for the installation.
Insert the card firmly into the slot and secure it with a screw before connecting your serial devices. Install the provided drivers from the Mini-CD or download the latest versions from the manufacturer website.
Keep the card free from dust and moisture to maintain consistent performance over time. Regularly check that all connections remain tight to prevent data loss or communication errors during operation.
Frequently Asked Questions
Do I need drivers for a Pcie Serial Port Card?
Yes most cards require driver installation for Windows systems to function correctly. Linux users may need to compile source code from the provided CD or download drivers from the manufacturer website.
Will a PCIe x1 card fit in a x16 slot?
Yes PCIe slots are backward compatible so a PCIe x1 card will fit and work correctly in a x16 x8 or x4 slot. The card will operate at x1 speed but this is sufficient for serial data transfer.
Can I use these cards with Linux?
Most cards support Linux kernels 2.6x through 5.x but require manual configuration or compiling source code from the included CD. Ensure you have the necessary permissions to install drivers on your Linux system.
What is the difference between a full profile and low profile bracket?
A full profile bracket is taller and fits standard desktop cases while a low profile bracket is shorter for slim or small form factor PCs. Many cards include both to ensure compatibility with different chassis types.
How do I connect a DB9 device to the new card?
Simply plug your DB9 serial device directly into the ports on the card's bracket. Ensure the cable is securely connected and the device is powered on before configuring the ports in your operating system.
Are these cards compatible with ARM systems?
Many modern cards based on ASIX chipsets support Intel AMD and ARM hardware platforms. However you should always verify specific ARM compatibility with the manufacturer before purchasing for embedded or specialized use.
Final Thoughts on Choosing the Best Pcie Serial Port Card
We have reviewed ten reliable options that range from budget dual-port solutions to premium single-port cards with advanced compliance features. Each choice offers unique benefits depending on your specific industrial or office connectivity needs.
When making your final decision prioritize chipset quality and bracket compatibility to ensure the card fits your system and performs reliably. Checking OS support early can save time and prevent driver conflicts during setup.
Prices and availability change frequently so remember to verify the current details on the retailer site before completing your purchase. With the right card you can restore essential legacy connectivity to your modern computer system easily.