BLACK BOX 

BLACK BOX SP390A-R3 GREAT FOR LINKING OLDER SERIAL DEVICES TO COMPUTERS OR LAPTOPS WITH USB PORTS. O

Mfg Part Number:  SP390A-R3  
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Price: $229.98
Quantity:
In Stock: 1
Last Updated: Oct 19, 2025
No Sales Tax except these states
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  • Great for linking older serial devices to computers or laptops with USB ports.
  • Offers 2-wire RS-485 or 4-wire RS-422/RS-485 operation.
  • Holds connections tight with its high-retention USB connector.
  • USB 1.0, USB 1.1, and USB 2.0 compatible (12 Mbps).
  • Interface powered. No external power required.
  • Serial terminal block can be removed for easy wiring.
  • LEDs indicate transmitting and receiving of data.

This compact device quickly converts USB port connections to RS-422/485 so you can connect legacy serial devices to a newer PC or laptop. Continue to use legacy commercial and industrial RS-422/485 devices without making any changes to the applications written for them.

Plus, because it features 2000-volt optical isolation, you can protect your PC and other equipment from dangerous spikes and surges on the RS-485/RS-422 network.

Simply plug it into your PC's USB port using the included USB cable (3-ft.), then configure its DIP switches for 2- or 4-wire operation. The converter will show up as an additional COM port in your PC's Windows Device Manager.

Main Specification
General Information
Manufacturer Black Box Corporation
Manufacturer Part Number SP390A-R3
Manufacturer Website Address http://www.blackbox.com
Brand Name Black Box
Product Model SP390A-R3
Product Name USB to RS422/485 Converter with Opto-Isolation
Product Type Transceiver/Media Converter
Interfaces/Ports
Total Number of Ports 2
USB Yes
Power Description
Power Source USB
Physical Characteristics
Height 3"
Width 1.7"
Depth 0.8"
Miscellaneous
Environmentally Friendly Yes
Environmental Compliance Waste Electrical and Electronic Equipment Directive (WEEE)
Environmental Compliance Restriction of Hazardous Substances (RoHS)
Country of Origin United States
TAA Compliant Yes
Warranty
Limited Warranty 5 Year
WARNING:: The plastic used in cable products can expose you to lead and lead components, chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm. For more information go to www.P65Warnings.ca.gov
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