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Black Box

Black Box USB to RS422/485 Converter with Opto-Isolation

$291.42
$222.32 SAVE $69.10
2 availableas of 09/07/2026

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Should arrive by Thu, Oct 1 with free ground shipping

Compliance, certifications and origin

  • TAA compliant
  • WEEE
  • RoHS
  • Origin: United States
Rated excellent by our customers Read our reviews

Secure checkoutISO 9001:2015 and CMMC certifiedFamily owned since 1982

Free shipping on most items when you spend $100 or more.

Real people answer: chat with us, email customerservice@colamco.com, or call 1-800-692-8757, Monday to Friday, 8am to 5pm EST.

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Secure checkoutISO 9001:2015 and CMMC certifiedFamily owned since 1982

Free shipping on most items when you spend $100 or more.

Real people answer: chat with us, email customerservice@colamco.com, or call 1-800-692-8757, Monday to Friday, 8am to 5pm EST.

Overview

  • 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.

Technical specifications

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

Green Compliant Yes
Country of Origin United States
TAA Compliant Yes
Environmental Compliance Waste Electrical and Electronic Equipment Directive (WEEE)Restriction of Hazardous Substances (RoHS)

Warranty

Limited Warranty 5 Year

Ratings and reviews

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Shipping and returns

Free shipping on most items when you spend $100 or more. In-stock items ship on the next open shipment slot. The buy box above shows the live order-by countdown and the estimated arrival date.

Need to send it back? Start a return online with a Request RMA and our team will take care of you. Keep the original packaging. Items must be returned in the condition received.

Questions about shipping or returns? Chat with us, email customerservice@colamco.com, or call 1-800-692-8757, Monday to Friday, 8am to 5pm EST.