Black Box SP390A-R3 | USB to RS422/485 Converter with Opto-Isolation

This refurbished Black Box SP390A-R3 | USB to RS422/485 Converter with Opto-Isolation is listed at $446.76 on Gotodirect via Dero. We compare prices across certified US sellers so you can find the best deal with warranty included.

Refurbished means the Black Box SP390A-R3 | USB to RS422/485 Converter with Opto-Isolation has been inspected, tested, and restored to full working order before resale. Cosmetic wear may vary by grade, but the device is fully functional and sold with seller warranty.

Refurbished Black Box SP390A-R3 | USB to RS422/485 Converter with Opto-Isolation models in the electronics category typically cost 20–50% less than new while including seller warranty and quality checks. Dero compares prices across US marketplaces so you can find the best offer for this exact model.

Review the condition grade, warranty length, return policy, and seller ratings on marketplaces. Confirm storage, color, and model year match what you need. All listings on Dero link to certified sellers with tested products.

Dero is a comparison engine — we find the best refurbished and secondhand deals across the US. When you click Buy, you complete your purchase directly on the certified seller's website, which handles payment, shipping, and customer support.

Contact the seller where you completed your purchase. Customer service details are usually in your order confirmation email from that marketplace.