When you need to connect legacy serial devices to your modern computer, you’ll want a reliable PCIe serial port card. You can choose from single-port or dual-port options, each offering different speeds and features to match your requirements. StarTech and other manufacturers provide cards with varying performance levels, bracket styles, and operating system support. But before you select one, you should understand what factors make each card suitable for your specific setup—which we’ll explore next.
| 2-Port PCI Express RS-232 Serial Card (PCIE-SE2) |
| Best Overall | Serial Ports: 2 ports | Maximum Data Transfer Rate: Not specified | UART Chipset: ASIX AX99100 | VIEW LATEST PRICE | Read Our Analysis |
| Single Port PCIe RS232 Serial Adapter Card |
| Budget-Friendly Pick | Serial Ports: 1 port | Maximum Data Transfer Rate: 250 Kbps | UART Chipset: MCS9922 | VIEW LATEST PRICE | Read Our Analysis |
| 2-Port PCIe Serial Expansion Card RS232 |
| Plug-and-Play Solution | Serial Ports: 2 ports | Maximum Data Transfer Rate: 230,400 Bps (230.4 Kbps) | UART Chipset: 16C550 | VIEW LATEST PRICE | Read Our Analysis |
| StarTech 2-Port PCI Express Serial Card (PEX2S1050) |
| Premium Performance | Serial Ports: 2 ports | Maximum Data Transfer Rate: 460 Kbps | UART Chipset: 16C1050 | VIEW LATEST PRICE | Read Our Analysis |
| StarTech.com PCIe to RS232 Serial Interface Card |
| High-Speed Leader | Serial Ports: 1 port | Maximum Data Transfer Rate: 921.6 Kbps | UART Chipset: ASIX AX99100 | VIEW LATEST PRICE | Read Our Analysis |
| PCIe Serial Expansion Card 2 Port RS232 Converter |
| Value Pick | Serial Ports: 2 ports | Maximum Data Transfer Rate: 250 Kbps (230.4 Kbps baud rate) | UART Chipset: WCH382L (16C450/16C550 compatible) | VIEW LATEST PRICE | Read Our Analysis |
| StarTech.com PCI Serial Parallel Combo Card (PCI2S1P2) |
| Professional Combo Card | Serial Ports: 2 serial ports (plus 1 parallel) | Maximum Data Transfer Rate: 115.2 Kbps (serial); 1.5 Mbps (parallel) | UART Chipset: Asix MCS9865 (16C550 UART) | VIEW LATEST PRICE | Read Our Analysis |
| Vantec 2-Port Serial PCIe Host Card (UGT-PCE20SR) |
| Compact & Compatible | Serial Ports: 2 ports | Maximum Data Transfer Rate: 230,400 Bps (230.4 Kbps) | UART Chipset: 16C950 compatible UART | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
2-Port PCI Express RS-232 Serial Card (PCIE-SE2)
The PCIE-SE2 is your best choice if you’re running a desktop or industrial PC that needs additional serial ports without replacing your entire system. This 2-port RS-232 card uses the ASIX AX99100 chipset and fits any PCIe slot—X1, X4, X8, or X16. You’ll get two DB9 serial ports for connecting legacy devices like POS systems, scanners, and industrial equipment. Installation requires downloading drivers for your OS; Windows users run an installer from the included Mini-CD, while Linux users compile source code. Switch to the low-profile bracket if you’re using a slim PC case.
- Serial Ports:2 ports
- Maximum Data Transfer Rate:Not specified
- UART Chipset:ASIX AX99100
- PCIe Slot Compatibility:x1, x4, x8, x16 slots
- Operating System Support:Windows XP/Vista/7/8.x/10/11; Linux 2.6.x-5.x
- Bracket Options:Full-size and low-profile brackets
- Additional Feature:256-byte depth FIFO transmit
- Additional Feature:Compatible with Intel/AMD/ARM
- Additional Feature:Switchable low-profile bracket
Single Port PCIe RS232 Serial Adapter Card
Need to add legacy serial connectivity to a modern computer system? This Single Port PCIe RS232 Serial Adapter Card solves that problem directly. The card installs into any available PCIe x1 slot and connects one DB9 serial port to your system. It features the MCS9922 chipset, which handles data transfers up to 250Kbps and supports standard 16C550 UART compatibility. You’ll get hardware and software flow control options plus adjustable serial formats from 5 to 8 bits. The low-profile design fits most computer cases without obstruction. Installation requires inserting the card, securing it with the bracket screw, then installing drivers for your operating system. After setup, you can immediately connect legacy serial devices like printers, modems, or industrial equipment.
- Serial Ports:1 port
- Maximum Data Transfer Rate:250 Kbps
- UART Chipset:MCS9922
- PCIe Slot Compatibility:x1 slot
- Operating System Support:Not specified
- Bracket Options:Low-profile bracket
- Additional Feature:Low-profile form factor
- Additional Feature:2.5Gbps PCIe throughput
- Additional Feature:5-8 bit serial format
2-Port PCIe Serial Expansion Card RS232
Looking to add reliable serial connectivity to your computer without replacing your entire system? The 2-Port PCIe Serial Expansion Card gives you two industrial DB9 RS232 COM ports through a single PCIe x1 slot. You’ll get 16C550 UARTs supporting speeds up to 230,400 Bps with automatic IRQ and IO address selection. Installation requires inserting the card into your PCIe slot, then installing drivers from the CH38XDRV CD. The card supports Windows 2000 through 11 and Linux. It works with IRQ sharing and includes a low-profile bracket for standard cases. Customer support provides solutions within 24 hours for any issues.
- Serial Ports:2 ports
- Maximum Data Transfer Rate:230,400 Bps (230.4 Kbps)
- UART Chipset:16C550
- PCIe Slot Compatibility:1-Lane PCI-Express x1
- Operating System Support:Windows 2000/XP/2003/Vista/7/8/10/11; Linux
- Bracket Options:Low-profile bracket included
- Additional Feature:Automatic IRQ/IO selection
- Additional Feature:Plug and play functionality
- Additional Feature:24-hour customer support
StarTech 2-Port PCI Express Serial Card (PEX2S1050)
If you’re running manufacturing equipment, point-of-sale systems, or security devices that rely on RS232 connections, the StarTech PEX2S1050 solves the problem of modern computers lacking serial ports. This 2-port PCI Express card adds two RS232 serial ports using 16C1050 UART channels, supporting data transfer rates up to 460Kbps. The card works with PCIe 1.0a and fits any slot size from 1x to 16x. Installation is straightforward: insert the card into your available PCIe slot and install the included drivers. The dual-channel UART handles simultaneous activity, reducing CPU load. You’ll receive two bracket options—standard and low-profile—ensuring compatibility with your case. The 2-year warranty and Windows support provide reliable connectivity for legacy devices on modern systems.
- Serial Ports:2 ports
- Maximum Data Transfer Rate:460 Kbps
- UART Chipset:16C1050
- PCIe Slot Compatibility:1x, 2x, 4x, 8x, 16x slots
- Operating System Support:Windows (modern systems)
- Bracket Options:Standard-profile and low-profile brackets
- Additional Feature:Dual-channel UART simultaneous activity
- Additional Feature:Reduced CPU load performance
- Additional Feature:2-year manufacturer warranty
StarTech.com PCIe to RS232 Serial Interface Card
The StarTech.com PCIe to RS232 Serial Interface Card is your solution when you’ve got legacy serial devices that won’t connect to modern computers. This single-port card uses the 16C1050 UART chipset to handle barcode scanners, printers, and industrial equipment at speeds up to 921.6 Kbps. Install it into your PCIe 2.0 x1 slot, then connect your DB9 serial cable with screw-locking connectors. The card supplies 5V or 12V power through pin 9, supports both Windows and Linux systems, and includes LED status lights for monitoring activity. Its COM Retention feature maintains port settings during system updates.
- Serial Ports:1 port
- Maximum Data Transfer Rate:921.6 Kbps
- UART Chipset:ASIX AX99100
- PCIe Slot Compatibility:PCIe 2.0 x1
- Operating System Support:Windows; Linux
- Bracket Options:Standard and low-profile brackets
- Additional Feature:Built-in LED status lights
- Additional Feature:5V/12V pin 9 power
- Additional Feature:COM retention feature
PCIe Serial Expansion Card 2 Port RS232 Converter
Need to connect legacy serial devices to a modern desktop PC without built-in COM ports? The GODSHARK WCH382L PCIe Serial Expansion Card provides two RS232 serial ports via a single PCI Express slot. Install the card into any available PCIe x1, x4, x8, or x16 slot on your desktop motherboard. Load the included driver CD and let your BIOS automatically assign I/O addresses and IRQ settings. Each port supports baud rates up to 230.4 Kbps with 16C450/16C550 UART compatibility. You’ll gain RTS/CTS and XON/XOFF flow control for reliable communication with modems, industrial equipment, and legacy peripherals. The card works with Windows, Linux, and older operating systems, making it ideal for POS terminals and ATM environments requiring stable serial connectivity.
- Serial Ports:2 ports
- Maximum Data Transfer Rate:250 Kbps (230.4 Kbps baud rate)
- UART Chipset:WCH382L (16C450/16C550 compatible)
- PCIe Slot Compatibility:x1, x4, x8, x16 slots
- Operating System Support:DOS, Windows 98/Me/NT4.0/2000/XP/Vista/7/8/Server 2003&2008; Linux
- Bracket Options:Not specified
- Additional Feature:16C450/16C550 UART compatibility
- Additional Feature:RTS/CTS XON/XOFF flow
- Additional Feature:BIOS-assigned I/O addressing
StarTech.com PCI Serial Parallel Combo Card (PCI2S1P2)
Looking to connect legacy serial and parallel devices to a modern computer? The StarTech.com PCI2S1P2 combo card installs in a single PCI slot, giving you two DB9 serial ports and one DB25 parallel port. The serial ports handle RS-232 connections at speeds up to 115.2 Kbps, supporting flow control options like RTS/CTS. The parallel port reaches 1.5 Mbps and accommodates multiple modes including ECP and EPP. Both port types include 256-byte FIFO buffers for smooth data transmission. Install the full-profile bracket or switch to low-profile brackets if your case requires it. Windows 7 through 11 and Linux 2.6 to 5.x provide driver support. This card works with printers, plotters, industrial equipment, and medical devices.
- Serial Ports:2 serial ports (plus 1 parallel)
- Maximum Data Transfer Rate:115.2 Kbps (serial); 1.5 Mbps (parallel)
- UART Chipset:Asix MCS9865 (16C550 UART)
- PCIe Slot Compatibility:PCI slot (not PCIe)
- Operating System Support:Windows 7/8/8.1/10/11; Windows Server 2008 R2/2012/2012 R2/2016/2019; Linux 2.6.x-5.x
- Bracket Options:Full-profile and 3x low-profile bracket options
- Additional Feature:1x DB25 parallel port
- Additional Feature:Lifetime warranty included
- Additional Feature:24/5 multilingual technical support
Vantec 2-Port Serial PCIe Host Card (UGT-PCE20SR)
You’ll find the Vantec UGT-PCE20SR ideal if you need to add serial connectivity to a modern computer without opening the case for internal upgrades. This PCIe card installs directly into your motherboard’s PCIe slot and provides two UART serial ports. It supports PCIe lanes x1, x4, x8, and x16, making it compatible with most systems. The card features 16C950 compatible UART technology and handles data transfer rates up to 230400 bps. Windows XP through Windows 8 systems recognize it automatically through Plug-n-Play functionality. Your BIOS assigns I/O addresses and IRQ settings without manual configuration required.
- Serial Ports:2 ports
- Maximum Data Transfer Rate:230,400 Bps (230.4 Kbps)
- UART Chipset:16C950 compatible UART
- PCIe Slot Compatibility:x1, x4, x8, x16 lanes
- Operating System Support:Windows XP, Vista, 7, 8
- Bracket Options:Not specified
- Additional Feature:16C950 compatible UART
- Additional Feature:BIOS assigns I/O addresses
- Additional Feature:Plug-and-play functionality
Factors to Consider When Choosing a PCIe Serial Port Card
You’ll need to evaluate five key factors before selecting a PCIe serial port card: first, confirm that the card’s compatibility matches your motherboard and existing hardware setup; second, determine your data transfer rate requirements based on your applications and devices; and third, count how many serial ports you actually need for your current and future devices. Next, verify that the card supports your operating system—whether that’s Windows, Linux, or macOS—since driver availability varies by manufacturer and OS version. Finally, check the physical form factor options available, such as full-height or low-profile designs, to ensure the card fits within your computer’s case and doesn’t conflict with adjacent expansion slots.
Compatibility With Your System
How do you know if a PCIe serial port card will work with your computer? First, match the card’s PCIe lane requirement (x1, x4, x8, or x16) to your motherboard’s available slot type. Second, verify your motherboard supports PCIe 1.0a or newer for proper electrical signaling and IRQ assignment. Third, check your operating system compatibility—confirm Windows version or Linux kernel support and verify drivers exist for your system. Fourth, examine your physical space: measure your case’s expansion slot openings and confirm the card’s bracket type (full-height or low-profile) fits your I/O panel. Finally, review the card’s UART chipset specifications against your serial devices’ data rate and flow-control requirements to ensure functional compatibility.
Data Transfer Rate Requirements
What speeds do your serial devices actually need? Review your equipment’s baud rate specifications first. Most PCIe serial cards support 230.4 Kbps to 921.6 Kbps per port, which covers standard industrial and legacy devices. Check if your application requires sustained high-speed transfers or handles occasional bursts. For sustained transfers, examine the card’s FIFO depth—256-byte buffers are common and help manage continuous data flow. If you’re using flow control (RTS/CTS or XON/XOFF), account for potential throughput reduction. Match your card’s maximum baud rate to your slowest device to avoid bottlenecks. Document all connected equipment speeds before purchasing. This prevents upgrading later when existing hardware can’t utilize faster capabilities.
Number Of Serial Ports Needed
Determining your port requirements starts with counting every serial device that’ll connect to your system—printers, industrial controllers, sensors, modems, and legacy equipment all demand their own connection. List each device and note whether you’ll operate them simultaneously or sequentially. Simultaneous operation requires separate ports on a multi-port card to prevent time-slicing delays. If you’re running just one device at a time, a single-port card suffices. However, anticipate future growth. Plan for at least one additional port beyond your current needs. Two-port and four-port cards offer practical middle grounds for most applications. Consider modular designs that allow port expansion later without replacing your entire card. This approach prevents costly upgrades and system downtime when your serial device count increases.
Operating System Support
Once you’ve settled on the number of ports you’ll need, you’ll want to verify that your chosen card actually works with your operating system before you buy it. Check the manufacturer’s compatibility list to confirm your exact OS version is supported—whether that’s Windows 7, 10, 11, or a specific Linux distribution and kernel version. Some cards require manual driver installation from a CD or compiled source code, while others support plug-and-play functionality. Verify whether the card works across multiple operating systems if you’re using both Windows and Linux. Additionally, confirm how the card handles IRQ and IO address assignment on your system, as this varies by operating system. These steps prevent purchasing incompatible hardware.
Physical Form Factor Options
Because your chassis dimensions and available slots directly affect which cards you can install, you’ll need to match the card’s physical form factor to your system before purchasing. PCIe serial cards come in two bracket styles: full-size standard brackets for regular desktop cases and low-profile slim brackets for compact systems. Check your chassis type first, then verify your available PCIe slot count and spacing. Most cards fit x1 slots but work in x4, x8, or x16 slots too. Consider whether you need single-port or dual-port configurations, as dual-port models require more physical length. Many manufacturers include both bracket types in packages, giving you flexibility. Measure your available space and confirm slot compatibility to ensure proper installation.
UART Chipset And Performance
What UART chipset your serial card uses will determine its core functionality and data-handling capability. Look for 16C550-compatible or ASIX AX99100 controllers, which offer proven performance and broad driver support. The UART chipset directly affects your maximum data rate—you’ll find speeds ranging from 230 to 460 Kbps depending on the model you select. Check the on-board FIFO depth; most quality cards feature 256-byte transmit buffers that enable smooth burst data transmission without overflow. Verify flow control options available on your card, including hardware RTS/CTS and XON/XOFF support. These features prevent data loss in high-traffic or electrically noisy environments. Match the chipset capabilities to your application’s speed and reliability requirements before purchasing.
Warranty And Technical Support
How long will your serial port card remain covered if a hardware defect occurs? Review the manufacturer’s warranty length, which typically ranges from 2 years to lifetime coverage. Check your product page for specific terms, as warranties cover hardware defects but exclude user damage or improper installation. Next, examine the support options available. Most manufacturers offer multi-channel technical assistance operating 24/5 or similar schedules. Confirm whether they provide driver updates and quick-start guides. Some vendors guarantee solution response times within 24 hours for reported issues. Access device-specific troubleshooting resources listed on the product page. Document your purchase details and warranty registration to verify coverage eligibility. Compare support responsiveness across brands before deciding, as faster assistance minimizes downtime and operational disruptions.
Final Thoughts
When you’re selecting a PCIe serial port card, you’ll need to match your requirements to available options. First, determine how many ports you need—single or dual. Next, check your OS compatibility and required data rates. Then, verify your system has available PCIe slots and appropriate bracket space. Finally, confirm warranty coverage and technical support meet your needs before purchasing.
Meet Ry, “TechGuru,” a 36-year-old technology enthusiast with a deep passion for tech innovations. With extensive experience, he specializes in gaming hardware and software, and has expertise in gadgets, custom PCs, and audio.
Besides writing about tech and reviewing new products, he enjoys traveling, hiking, and photography. Committed to keeping up with the latest industry trends, he aims to guide readers in making informed tech decisions.