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Gray USB 2.0 to DB9 serial converter with DIP switches and LEDs

CoolGear

CoolGear RS-232/422/485 USB 2.0 Converter Isolated 2.5kV Surge 600W

SKU CH-3531-5XGRA

Converts USB 2.0 to RS-232, RS-422 or RS-485 with 2.5 kV isolation and 600 W surge protection

  • Adapter typeUSB to DB9 (RS-232)
  • First connector1x USB 2.0 Type B female
  • Second connector1x DB-9 male
  • Product colorGray
  • Switch between RS-232, RS-422, RS-485 via DIP switch
  • 5 kV optical isolation shields devices from electrical interference
  • 600 W surge protection per line guards against voltage spikes
  • USB 2.0 plug-and-play with no external power required
  • COM port retained after reboot with TX/RX LED status

Industrial Serial Adapter

This USB 2.0 converter links legacy RS-232, RS-422 and RS-485 equipment to modern computers. It targets technicians who connect barcode scanners, label printers, time clocks or point-of-sale terminals in industrial or commercial settings. Optical isolation rated at 2.5 kV and 600 W surge protection per line shield both sides from electrical noise and voltage spikes. The DB-9 male connector and USB Type-B female port fit standard cables without gender changers.

Upgrade From Basic Converters

The unit replaces simple, non-isolated USB-to-serial cables that lack surge protection and multi-standard switching. The jump is worth it when equipment operates near motors, welding gear or long cable runs where ground loops and transients damage unprotected ports. External DIP switches select RS-232, RS-422 or RS-485 modes on the fly, supporting up to 921.6 Kbps on RS-232 and 3 Mbps on RS-422/485. COM-port assignments survive reboots, avoiding reconfiguration after restarts.

Driver-First Installation

Windows 11, 10, 7, Vista, XP, 2000, 98, CE, Linux and MacOS are supported, but the driver must be installed before plugging in the hardware. A supplied driver disc and terminal block are included; the USB screw-lock cable prevents accidental disconnection. Common issues arise when users connect the adapter before running the installer, causing the OS to bind a generic driver that blocks the correct one. The adapter draws power from the USB bus, so no external supply is needed.

How it compares

Measured against everything we stock in USB Adapter Cables & Dongles, at today’s prices. Recalculated every night.

Price $102.99
Pricier than about 91% of the 1,430 comparable items (median $14.99).

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Specifications

Product
Product colorGray
Adapter typeUSB to DB9 (RS-232)
Ports & slots
First connector1x USB 2.0 Type B female
Second connector1x DB-9 male

Questions about this item

What DB-9 connector and USB 2.0 Type B port does the adapter use for mounting?

The unit provides one DB-9 male connector for the serial side and one USB 2.0 Type B female port for the host connection.

How do the external DIP switches select RS-232, RS-422 or RS-485, and what step is often missed?

Set the DIP switches to the desired standard before plugging the adapter into the USB port; the mode is read only at enumeration.

Which replaceable parts ship with the converter for long-term use?

A terminal block and a USB screw-lock cable are included for field replacement if the originals wear out.

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