A serial port card keeps older gear working on modern PCs.
It adds RS-232 ports for devices like barcode scanners, industrial tools, and older printers.
PCIe cards with 2 or 4 ports are common, and combo models add parallel support too.
The right pick comes down to your setup, port count, and daily use.
| SIIG Dual Serial and Parallel Port PCIe Card (JJ-E20411-S1) |
| Best for Legacy Gear | Port Count: 2 serial, 1 parallel | Interface: PCIe x1 | Serial Standard: RS-232 | VIEW LATEST PRICE | Read Our Analysis |
| PCIe 4-Port RS232 Serial Adapter Card |
| Best 4-Port Pick | Port Count: 4 serial | Interface: PCIe | Serial Standard: RS232 | VIEW LATEST PRICE | Read Our Analysis |
| StarTech.com 2-Port PCIe Serial Card (PEX2S1050) |
| Best High-Speed Option | Port Count: 2 serial | Interface: PCIe | Serial Standard: RS232 | VIEW LATEST PRICE | Read Our Analysis |
| 2-Port PCIe RS-232 Serial Card (PCIe1X) |
| Best Compatibility | Port Count: 2 serial | Interface: PCIe x1 | Serial Standard: RS-232 | VIEW LATEST PRICE | Read Our Analysis |
| LINDY 2 Port RS-232 Serial and 1 Port Parallel Card PCI Express (51188) |
| Best Dual-Function Card | Port Count: 2 serial, 1 parallel | Interface: PCIe | Serial Standard: RS-232 | VIEW LATEST PRICE | Read Our Analysis |
| 2-Port PCIe RS-232 Serial Port Card (PCIE-SE2) |
| Best for Industrial Use | Port Count: 2 serial | Interface: PCIe x1 | Serial Standard: RS-232 | VIEW LATEST PRICE | Read Our Analysis |
More Details on Our Top Picks
SIIG Dual Serial and Parallel Port PCIe Card (JJ-E20411-S1)
Should you need a compact expansion card for legacy hardware, the SIIG Dual Serial and Parallel Port PCIe Card (JJ-E20411-S1) is a strong fit. You get two RS-232 serial ports and one IEEE 1284 parallel port on a PCIe x1 card that works with Windows 10. It supports 16C550/16C650 UARTs, hardware and software flow control, and data rates up to 250 Kbps. The parallel port handles SPP, Byte, and ECP modes, plus 5V or 12V output for powered devices. Its dual-profile design fits full-height or low-profile systems.
- Port Count:2 serial, 1 parallel
- Interface:PCIe x1
- Serial Standard:RS-232
- Data Rate:250 Kbps
- Bracket Size:Full-height / low-profile
- OS Support:Windows 10
- Additional Feature:5V/12V power output
- Additional Feature:Dual-profile design
- Additional Feature:Hardware/software flow control
PCIe 4-Port RS232 Serial Adapter Card
The PCIe 4-Port RS232 Serial Adapter Card is a strong choice whenever you need four reliable serial connections for POS, ATM, or industrial automation systems. You get a PCIe adapter with four independent 9-pin RS232 ports that work like built-in serial interfaces. It supports modem control, hot swap, and stable data transmission, so you can cut data loss and keep devices talking smoothly. With speeds up to 250Kbps, it fits demanding setups. You can use it on Windows 7, 8, 10, or Linux, making integration easier.
- Port Count:4 serial
- Interface:PCIe
- Serial Standard:RS232
- Data Rate:250 Kbps
- Bracket Size:Unspecified
- OS Support:Windows 7/8/10, Linux
- Additional Feature:4 independent ports
- Additional Feature:POS and ATM use
- Additional Feature:Hot swap support
StarTech.com 2-Port PCIe Serial Card (PEX2S1050)
StarTech.com’s 2-Port PCIe Serial Card (PEX2S1050) is a smart pick whenever you need reliable RS232 connectivity for older or specialized gear, especially in system upgrades, manufacturing equipment, POS terminals, or security devices. You get two DB9 serial ports through a PCIe 1.0a card that fits 1x through 16x slots. Its 16C1050 UART supports data rates up to 460 Kbps, so you can move commands quickly and reliably. The card installs easily with plug-and-play support, IRQ sharing, and includes standard- and low-profile brackets. It’s TAA compliant too.
- Port Count:2 serial
- Interface:PCIe
- Serial Standard:RS232
- Data Rate:460 Kbps
- Bracket Size:Standard / low-profile
- OS Support:Unspecified
- Additional Feature:16C1050 UART
- Additional Feature:IRQ sharing
- Additional Feature:TAA compliant
2-Port PCIe RS-232 Serial Card (PCIe1X)
For desktop PCs or industrial devices that need two reliable DB9 connections, this 2-Port PCIe RS-232 Serial Card gives you an easy expansion path through a single PCIe x1 slot. You can install it in X1, X4, X8, or X16 motherboard slots, then connect POS gear, scanners, printers, security systems, and testing equipment. Its ASIX AX99100 chipset and 256-byte FIFO help keep serial data steady. You get Windows and Linux support across 32- and 64-bit systems. A full-size bracket ships with desktop hardware, and low-profile brackets fit slim PCs too.
- Port Count:2 serial
- Interface:PCIe x1
- Serial Standard:RS-232
- Data Rate:Unspecified
- Bracket Size:Full-size / low-profile
- OS Support:Windows/Linux
- Additional Feature:ASIX AX99100 solution
- Additional Feature:256-byte FIFO
- Additional Feature:Intel AMD ARM compatibility
LINDY 2 Port RS-232 Serial and 1 Port Parallel Card PCI Express (51188)
LINDY’s 2 Port RS-232 Serial and 1 Port Parallel Card PCI Express (51188) is a smart fit whenever you need to add both legacy serial and parallel connections to a PCIe system, especially in older Windows environments or Linux setups. You can install it in PCI Express 1.1 systems and keep older gear talking through two 9-way D male serial ports. It supports Windows 2000, XP, Vista, 7, Server 2003, and Server 2008, plus Linux. Your serial links can reach 921 Kbps, while the parallel port runs up to 15 Mbps, so you get solid speed for classic devices.
- Port Count:2 serial, 1 parallel
- Interface:PCIe
- Serial Standard:RS-232
- Data Rate:921 Kbps
- Bracket Size:Unspecified
- OS Support:Windows 2000-7, Linux
- Additional Feature:1 port parallel
- Additional Feature:921 Kbps serial
- Additional Feature:15 Mbps parallel
2-Port PCIe RS-232 Serial Port Card (PCIE-SE2)
The 2-Port PCIe RS-232 Serial Port Card (PCIE-SE2) is a smart choice should you need to add two DB9 serial connections to a desktop or industrial system, especially whenever you’re working with POS terminals, scanners, printers, or control equipment. You get a PCIe x1 card that fits x1, x4, x8, or x16 slots and uses the ASIX AX99100 chip with a 256-byte FIFO. It supports Intel, AMD, and ARM platforms. Install the right driver for Windows or compile the Linux source. Use the full-size bracket, or swap in the low-profile brackets for slim PCs.
- Port Count:2 serial
- Interface:PCIe x1
- Serial Standard:RS-232
- Data Rate:Unspecified
- Bracket Size:Full-size / low-profile
- OS Support:Windows 7-11, Linux
- Additional Feature:ASIX AX99100 solution
- Additional Feature:256-byte transmit FIFO
- Additional Feature:Source code compile
Factors to Consider When Choosing Serial Port Cards
When you choose a serial port card, start with matching the port count to your setup and confirming the interface fits your system. You’ll also want to check operating system support, serial speed requirements, and whether the bracket and form factor suit your chassis. Picking the right mix of these factors helps you avoid compatibility issues and future upgrades.
Port Count Needs
Start starting with matching the card’s port count to the number of serial devices you need to connect, since most cards come with 1 to 4 RS-232 ports. If you’ve got only two devices, like a printer and a scanner, a 2-port card usually fits best and leaves no ports sitting idle. When you’re wiring several independent devices, such as POS terminals, ATMs, or industrial controllers, a 4-port card can handle more connections and reduce the need for extra expansion cards. You should also consider combo cards about whether your setup needs serial links plus one IEEE 1284 parallel port for older peripherals. Opting for extra ports now can make sense considering you expect growth later, especially whenever another device would cost you a PCIe slot.
Interface Compatibility
Before you buy a serial port card, make sure its interface matches your system’s available expansion slot, whether that means a PCI Express x1 card in an x4, x8, or x16 slot. Then confirm the card speaks the same communication standard as your devices, like RS-232, so the connection works correctly. Check the connector type too: you might need DB9 serial ports or even a parallel port for certain legacy gear. Should your chassis be tight, choose a full-height or low-profile bracket that fits without forcing. Don’t assume every card uses the same physical layout or connector arrangement. Matching these hardware details upfront saves you from returns, adapter hassles, and installation delays whenever you’re trying to keep older equipment running smoothly.
Operating System Support
Once the card fits your slot and connectors, make sure its drivers match your operating system, because support can vary widely between older platforms like Windows XP or 2000 and newer ones like Windows 10 and 11. Check the manufacturer’s compatibility list before you buy, and don’t assume a card that works on one machine will work on another. If you move between platforms, choose a model that supports several versions, including Windows 7, 8, 10, Linux, and, when needed, server editions. For Linux, verify kernel support and whether you’ll need to compile driver source. Also confirm 32-bit and 64-bit support so upgrades don’t break your setup. Some cards need manual driver installation, so review the setup steps and download options first.
Serial Speed Requirements
Whenever you choose a serial port card, check its maximum baud rate and make sure it matches your devices’ real needs, since support can range from 250 Kbps to 460 Kbps or even 921 Kbps. You should also match the card’s speed to your slowest device, so you don’t push equipment beyond what it can handle. Whenever you run printers, POS terminals, scanners, or industrial controllers, pick a card that can keep up without delays or dropped data. Higher-speed cards help whenever you move larger serial data loads or need quicker response times. Lower-speed cards can still work fine for basic RS-232 tasks. In mixed setups, confirm each port lets you set a stable, compatible rate for every device.
Bracket And Form Factor
A serial port card’s bracket and form factor can make or break the installation, so check whether it includes both full-height and low-profile brackets before you buy. You need the right bracket height for your case, whether you’re fitting a standard tower or a slim chassis. Some cards ship with only a standard bracket and an optional low-profile one, so verify the physical profile before ordering. Should you be working with a small form factor system, pick a card that explicitly includes low-profile brackets to avoid clearance problems. Also, confirm the expansion card matches the slot space inside your case; PCIe compatibility alone isn’t enough. Should you might move the card between systems, a dual-profile design gives you more flexibility and saves you from buying again.
Device Use Cases
Match the serial port card to the devices you actually need to connect, since printers, scanners, POS terminals, industrial control gear, security systems, and logistics equipment all have different requirements. For point-of-sale or ATM systems, you’ll want stable RS-232 support and modem control to help prevent data loss during nonstop transactions. When you’re handling mixed legacy peripherals, check whether the card also offers a parallel port for handheld scanners, table scanners, or POS displays. Count your ports carefully: a simple setup needs just two, while busier installations often need four independent serial links. Finally, confirm that the interface matches your gear’s signaling and speed, since many serial devices run up to 250 Kbps over standard DB9 RS-232 connections.
Frequently Asked Questions
Can Serial Port Cards Work With Modern Windows and Linux Systems?
Yes, serial port cards can work on modern Windows and Linux systems if the card uses a supported PCIe chipset and has the proper drivers. Check that the card is compatible with your motherboard slot and that your Linux kernel includes support for it.
Do These Cards Support Both DB9 and DB25 Legacy Connectors?
Yes. Some cards support both DB9 and DB25 connectors, but you will usually need different brackets, cables, or adapters. Check the card’s port headers and bundle details, since support varies by model.
Is a PCIE Serial Card Better Than a Usb-To-Serial Adapter?
A PCIe serial card usually outperforms a USB to serial adapter when reliability and low latency matter. It provides more stable interrupts, fewer driver issues, and better compatibility with older hardware.
How Do I Verify COM Port Settings for Older Equipment?
You can verify COM port settings by opening Device Manager, confirming the port number, and comparing the baud rate, parity, data bits, stop bits, and flow control in your software with the device manual before testing.
Can One Card Connect to Multiple Legacy Devices at Once?
Yes. One card can connect to several legacy devices at the same time if it has enough ports. If the card has too few ports, use a multiport card or a splitter. Match each device’s baud rate, handshaking, and protocol settings.
Conclusion
Whenever you’re keeping legacy gear in the game, the right serial port card can save you time, money, and headaches. Whether you need a simple 2-port RS-232 adapter, a high-density 4-port card, or a combo model with parallel support, there’s a solid fit for your setup. Don’t let old hardware become dead weight—pick the card that matches your workflow, and you’ll keep everything running like a well-oiled machine.
