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Black metal box with DIN rail bracket and four DB9 ports

SerialGear

SerialGear USB-4COMi-SI-M USB to Quad RS-422/485 serial adapter

SKU CH-WZM6-HZ2F1

Adds four RS-422 or RS-485 ports via USB with 2000V optical isolation and 25KV ESD protection

  • Connector count4
  • Product colorBlack
  • DetailsSerial Modes: RS422, RS485
  • Adds four RS-422 or RS-485 serial ports via USB connection
  • 2000 V DC optical isolation protects the host from network spikes
  • 25 KV ESD surge protection withstands heavy electrostatic discharge
  • Baud rates up to 921.6 K bps for fast serial communication
  • SECC metal chassis with DIN rail bracket suits industrial mounting

USB to Quad RS-422/485 Adapter

The SerialGear USB-4COMi-SI-M adds four RS-422 or RS-485 serial ports to a computer through a single USB connection. It is designed for industrial automation, point-of-sale systems and long-distance serial communication in harsh environments. The SECC metal chassis includes a DIN-rail bracket for secure cabinet mounting.

Driver Installation and Wiring Notes

The adapter installs as a standard Windows COM port and supports Linux and Mac OS 10.X without proprietary software. Wiring must match the chosen mode: RS-422 uses Tx-, Tx+, Rx+, Rx-, GND and handshake lines while RS-485 four-wire uses Tx-, Tx+, Rx+, Rx- and two-wire uses data-, data+. Incorrect pin assignment is the most common cause of communication failure.

Industrial Users Needing Isolation

This unit suits engineers integrating barcode readers, scales, time clocks or multi-drop data collection devices where 2000V DC optical isolation and 25KV ESD protection are required. Buyers who need only a single port or who require USB-C connectivity should look at something else.

How it compares

Measured against everything we stock in RS-232 Serial Cables, at today’s prices. Recalculated every night.

Price $262.99
Pricier than about 96% of the 93 comparable items (median $21.99).

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Specifications

Product
Brand nameSERIALGEAR
Model nameUSB-4COMi-SI-M
Product colorBlack
Ports & slots
Connector count4

Questions about this item

How can I verify the USB-4COMi-SI-M is working after installation?

Open Device Manager on Windows or run dmesg on Linux to confirm four new COM ports appear, then use a terminal program to send test data at up to 921.6K bps and check for echo on the DB9 pins.

What comes with the USB-4COMi-SI-M and what must I source separately?

The adapter includes four DB9 male connectors, a SECC metal chassis with DIN-rail bracket, and the USB cable; you must provide RS-422 or RS-485 cables and any terminal devices.

Which serial mode should I select for my RS-422 or RS-485 equipment?

Choose RS-422 for full-duplex point-to-point links using Tx-, Tx+, Rx+, Rx-, GND, RTS and CTS lines, or RS-485 for half-duplex multi-drop wiring with data- and data+ pairs.

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