Best Serial Port Cards Under $200 (2026)
We ranked devices under $200 by interface support, build and mounting options, UART/throughput features, and overall value score
The Verdict
- Best Overall: HF2211 Serial Port Server: RS232/485/422 to Ethernet DTU — Best for networked serial: compact DTU that converts RS-232/485/422 to Ethernet for remote device access
- Best Value: 2-Port ISA Serial/Parallel Expansion Card — Best for legacy PCs: two-port ISA expansion that restores serial and parallel connectivity for older systems
This roundup evaluates serial port cards and converters under $200 that add RS-232/422/485 connectivity or convert serial to Ethernet for industrial, legacy, and hobbyist use. Selections prioritize interface support, build quality, driver/OS compatibility, and value to help you match a serial solution to your project needs
Top Picks
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1
Best Overall HF2211 Serial Port Server: RS232/485/422 to Ethernet DTU
Best for networked serial: compact DTU that converts RS-232/485/422 to Ethernet for remote device access
HF2211 converts RS232/485/422 serial interfaces to Ethernet for networked devices. Enables remote access and Ethernet DTU networking with multiple certifications for safety and compliance
- multi-interface serial support
- Ethernet DTU capability
- compliance certifications
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2
Best Value 2-Port ISA Serial/Parallel Expansion Card
Best for legacy PCs: two-port ISA expansion that restores serial and parallel connectivity for older systems
Retro ISA interface card with 2 RS232 ports (COM1/COM2) and a 5V powered PCI-like adapter. Works in vintage systems with ISA slots; supports DB15 and pin header COM2. Customer says it works with printers
- two RS232 ports
- DB15 and pin header interfaces
- requires only 5V power
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3
USR-DR301 DIN-Rail RS232 to Ethernet Converter
Best for DIN-rail installations: RS-232 to Ethernet device server designed for rack and industrial mounting
DIN-rail RS232 to Ethernet device server with compact size. Enables remote serial access via Ethernet/Websocket. Customer note hints ease of use
- DIN-rail mounted
- RS232 to Ethernet
- Websocket capable
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4
RS232/485/422 to RJ45 Ethernet module with POE
Best for PoE setups: RS-232/485/422 to RJ45 module that supports Power over Ethernet for simplified wiring
Industrial data gateway converting serial protocols to TCP/IP, supporting multi-function serial server and gateways. Useful for data acquisition and monitoring. Customer note: reliability is good, though documentation quality and setup ease are mixed
- POE capable Ethernet module
- bi-directional transparent transmission
- serial to TCP/IP with multiple gateway features
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5
StarTech 4 Port RS232 PCIe Serial Card with 16650 UART
Best for multiport PCIe needs: four-port RS-232 serial card with 16650 UART for robust serial host connections
Four RS232 ports with high-speed data transfer, featuring 16650 UART and 256-byte FIFO. Includes 4x 30cm IDC to DB9 cables. Suitable for PCI Express systems
- four high speed rs232 ports
- 16650 uart performance
- includes serial cables
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6
BLACK BOX IC820A RS-232 to RS-422/485 Bidirectional Converter
Best for protocol conversion: bidirectional RS-232 to RS-422/485 converter offering reliable signal level translation
RS-232 to RS-422/485 bidirectional converter for serial connections. Useful for integrating legacy serial devices with multi-protocol interfaces. Customer sentiment notes solid value and quality
- RS-232 to RS-422/485 compatibility
- bidirectional data flow
- premium build quality